ASTM D4929-22

Standard Test Method for Determination of Organic Chloride Content in Crude Oil

SIGNIFICANCE AND USE
5.1 Organic chlorides do not occur naturally in crude oil. When present, they result from contamination in some manner, such as disposal of chlorinated solvent used in many dewaxing pipeline or other equipment operations.  
5.1.1 Uncontaminated crude oil will contain no detectable organic chloride, and most refineries can handle very small amounts without deleterious effects.
5.1.1.1 Most trade contracts specify that no organic chloride is present in the crude oil.  
5.1.2 Several pipelines have set specification limits at  
5.1.2.1 To ensure Eq 3).  
5.1.3 Organic chloride present in the crude oil (for example, methylene chloride, perchloroethylene, etc.) is usually distilled into the naphtha fraction. Some compounds break down during fractionation and produce hydrochloric acid, which has a corrosive effect. Some compounds survive fractionation and are destroyed during hydro-treating (desulfurization of the naphtha).  
5.2 Other halides can also be used for dewaxing crude oil; in such cases, any organic halides will have similar impact on the refining operations as the organic chlorides.  
5.3 Organic chloride species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreating or reforming reactors and the acid accumulates in condensing regions of the refinery. Unexpected concentrations of organic chlorides cannot be effectively neutralized and damage can result. Organic chlorides are not known to be naturally present in crude oils and usually result from cleaning operations at producing sites, pipelines, or tanks. It is important for the oil industry to have common methods available for the determination of organic chlorides in crude oil, particularly when transfer of custody is involved.
SCOPE
1.1 The procedures in this test method cover the determination of organic chloride (above 1 μg/g organically-bound chlorine) in crude oils, using either distillation and sodium biphenyl reduction, distillation and microcoulometry, or distillation and X-ray fluorescence (XRF) spectrometry.  
1.2 The procedures in this test method involve the distillation of crude oil test specimens to obtain a naphtha fraction prior to chloride determination. The chloride content of the naphtha fraction of the whole crude oil can thereby be obtained. See Section 6 regarding potential interferences.  
1.3 Procedure A covers the determination of organic chloride in the washed naphtha fraction of crude oil by sodium biphenyl reduction followed by potentiometric titration.  
1.4 Procedure B covers the determination of organic chloride in the washed naphtha fraction of crude oil by oxidative combustion followed by microcoulometric titration.  
1.5 Procedure C covers the determination of organic chloride in the washed naphtha fraction of crude oil by X-ray fluorescence spectrometry.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6.1 The preferred concentration units are micrograms of chloride per gram of sample, though milligrams of chloride per kilogram of sample is commonly used for Procedure C.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2022
• ICS: 75.040 - Crude petroleum
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.03 - Elemental Analysis

Relations

• Refers: ASTM D6708-24 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-Mar-2024
• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D86-23a - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D86-23ae1 - Standard Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
• Effective Date: 01-Dec-2023
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Dec-2023
• Refers: ASTM D6299-23a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D6300-19a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2019
• Refers: ASTM D6708-19 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-May-2019
• Refers: ASTM D6708-18 - Standard Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport to Measure the Same Property of a Material
• Effective Date: 01-Apr-2018
• Refers: ASTM D6299-17b - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Dec-2017
• Refers: ASTM D6299-17a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Nov-2017
• Refers: ASTM D7343-12(2017) - Standard Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methods for Elemental Analysis of Petroleum Products and Lubricants
• Effective Date: 01-Jun-2017
• Refers: ASTM D6299-17 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Jan-2017

Overview

ASTM D4929-22 is the internationally recognized standard test method developed by ASTM International for the determination of organic chloride content in crude oil. Organic chlorides are not naturally present in crude oil and typically result from contamination-often due to the improper disposal of chlorinated solvents used in pipeline maintenance or equipment cleaning. As these compounds can severely impact petroleum refining processes, reliable and uniform test methods are essential for crude oil quality assurance, regulatory compliance, and safe, efficient refinery operation.

Key Topics

Scope of the Standard:

• Addresses the measurement of organic chlorides in crude oils at concentrations above 1 μg/g.
• Outlines three validated procedures:
  • Sodium biphenyl reduction and potentiometric titration
  • Oxidative combustion followed by microcoulometric titration
  • X-ray fluorescence (XRF) spectrometry
• Specifies distillation to obtain a naphtha fraction for chloride determination.
• Establishes preferred units as micrograms of chloride per gram of sample.
• Developed in line with international trade and technical barriers to trade (TBT) principles.

Significance and Use:

• Organic chlorides can generate corrosive hydrochloric acid during refining, damaging equipment and leading to operational issues.
• Even trace levels can cause significant issues if not properly monitored.
• Most trade contracts require crude oil to be free of organic chlorides.
• Pipelines often set strict specification limits for organic chloride content in both crude oil and naphtha fractions.

Test Methods:

• Distillation to isolate the naphtha fraction.
• Analytical procedures tailored to industry needs for sensitivity, speed, and reliability.
• Method selection may depend on available laboratory equipment and specific refinery or regulatory requirements.

Applications

Industry and Practical Value:

• Quality Assurance: Ensures crude oil meets contract and industry requirements for organic chloride content.
• Refinery Protection: Identifies contamination to prevent equipment corrosion and degradation, particularly in hydrotreating and reforming units.
• Regulatory Compliance: Supports compliance with pipeline and refinery chloride specifications.
• Transfer of Custody: Provides an objective measure for verifying crude oil quality during ownership or shipment transfers.

Where Used:

• Refineries: For incoming crude oil testing prior to processing.
• Pipeline Operators: To verify compliance with transport specifications and avoid downstream contamination.
• Crude Oil Producers: During process control to avoid the introduction of chlorinated compounds.
• Testing Laboratories: As a reference method for crude oil and related hydrocarbon streams.

Related Standards

The standard references several other ASTM methods and practices, including:

• ASTM D86: Distillation of Petroleum Products and Liquid Fuels
• ASTM D1193: Specification for Reagent Water
• ASTM D4057 / D4177: Manual and Automatic Sampling of Petroleum and Petroleum Products
• ASTM D4175: Terminology Related to Petroleum Products, Liquid Fuels, and Lubricants
• ASTM D6299: Statistical Quality Assurance and Control Charting
• ASTM D7343: X-ray Fluorescence Spectrometry Methods for Elemental Analysis

Additional supporting documents cover sampling techniques, precision and bias evaluation, and terminology consistency for petroleum products.

---

By implementing the ASTM D4929-22 standard, oil industry professionals gain consistent, reliable, and internationally accepted methods to identify and control organic chloride contaminants-protecting refinery assets, ensuring product quality, and supporting seamless global crude oil trade.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4929 − 22
Standard Test Method for
Determination of Organic Chloride Content in Crude Oil
This standard is issued under the fixed designation D4929; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 The procedures in this test method cover the determi-
nation of organic chloride (above 1 µg/g organically-bound
2. Referenced Documents
chlorine) in crude oils, using either distillation and sodium
2.1 ASTM Standards:
biphenyl reduction, distillation and microcoulometry, or distil-
lation and X-ray fluorescence (XRF) spectrometry. D86 Test Method for Distillation of Petroleum Products and
Liquid Fuels at Atmospheric Pressure
1.2 The procedures in this test method involve the distilla-
D1193 Specification for Reagent Water
tion of crude oil test specimens to obtain a naphtha fraction
D4057 Practice for Manual Sampling of Petroleum and
prior to chloride determination. The chloride content of the
Petroleum Products
naphtha fraction of the whole crude oil can thereby be
D4175 Terminology Relating to Petroleum Products, Liquid
obtained. See Section 6 regarding potential interferences.
Fuels, and Lubricants
1.3 Procedure A covers the determination of organic chlo-
D4177 Practice for Automatic Sampling of Petroleum and
ride in the washed naphtha fraction of crude oil by sodium
Petroleum Products
biphenyl reduction followed by potentiometric titration.
D6299 Practice for Applying Statistical Quality Assurance
and Control Charting Techniques to Evaluate Analytical
1.4 Procedure B covers the determination of organic chlo-
Measurement System Performance
ride in the washed naphtha fraction of crude oil by oxidative
D6300 Practice for Determination of Precision and Bias
combustion followed by microcoulometric titration.
Data for Use in Test Methods for Petroleum Products,
1.5 Procedure C covers the determination of organic chlo-
Liquid Fuels, and Lubricants
ride in the washed naphtha fraction of crude oil by X-ray
D6708 Practice for StatisticalAssessment and Improvement
fluorescence spectrometry.
of Expected Agreement Between Two Test Methods that
1.6 The values stated in SI units are to be regarded as
Purport to Measure the Same Property of a Material
standard. No other units of measurement are included in this
D7343 Practice for Optimization, Sample Handling,
standard.
Calibration, and Validation of X-ray Fluorescence Spec-
1.6.1 The preferred concentration units are micrograms of
trometry Methods for Elemental Analysis of Petroleum
chloridepergramofsample,thoughmilligramsofchlorideper
Products and Lubricants
kilogram of sample is commonly used for Procedure C.
3. Terminology
1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1 Definitions:
responsibility of the user of this standard to establish appro-
3.1.1 For definitions of terms used in this test method, refer
priate safety, health, and environmental practices and deter-
to Terminology D4175.
mine the applicability of regulatory limitations prior to use.
3.2 Definitions of Terms Specific to This Standard:
1.8 This international standard was developed in accor-
3.2.1 naphtha fraction, n—the fraction of the crude oil
dance with internationally recognized principles on standard-
collected from atmospheric distillation over a boiling range up
ization established in the Decision on Principles for the
to 204 °C.
Development of International Standards, Guides and Recom-
3.2.2 organic chloride compounds, n—compounds contain-
ing carbon and at least one chlorine.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.03 on Elemental Analysis. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2022. Published October 2022. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1989. Last previous edition approved in 2019 as D4929 – 19a. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D4929-22. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4929 − 22
3.2.3 total organic chloride compounds, n—the sum of 5. Significance and Use
compounds containing carbon and at least one chlorine.
5.1 Organic chlorides do not occur naturally in crude oil.
4. Summary of Test Method When present, they result from contamination in some manner,
such as disposal of chlorinated solvent used in many dewaxing
4.1 A crude oil distillation is performed to obtain the
pipeline or other equipment operations.
naphtha cut at 204 °C (400 °F). The distillation method was
5.1.1 Uncontaminated crude oil will contain no detectable
adaptedfromTestMethodD86forthedistillationofpetroleum
organic chloride, and most refineries can handle very small
products. The naphtha cut is washed with caustic, repeatedly
amounts without deleterious effects.
when necessary, until all hydrogen sulfide is removed. The
5.1.1.1 Mosttradecontractsspecifythatnoorganicchloride
naphtha cut, free of hydrogen sulfide, is then washed with
is present in the crude oil.
water, repeatedly when necessary, to remove inorganic halides
(chlorides). 5.1.2 Several pipelines have set specification limits at
<1 mg⁄kg organic chlorides in the whole crude, and <5 mg⁄kg
4.2 There are three alternative procedures for determination
in the light naphtha, on the basis of the naphtha fraction being
of the organic chloride in the washed naphtha fraction, as
20 % of the original sample.
follows.
5.1.2.1 To ensure <1 mg⁄kg organic chloride in the crude
4.2.1 Procedure A, Sodium Biphenyl Reduction and
oil, the amount measured in the naphtha fraction shall be <1/f
Potentiometry—The washed naphtha fraction of a crude oil
(where f is the naphtha fraction calculated with Eq 3).
specimen is weighed and transferred to a separatory funnel
5.1.3 Organic chloride present in the crude oil (for example,
containing sodium biphenyl reagent in toluene. The reagent is
methylene chloride, perchloroethylene, etc.) is usually distilled
an addition compound of sodium and biphenyl in ethylene
into the naphtha fraction. Some compounds break down during
glycol dimethyl ether. The free radical nature of this reagent
fractionation and produce hydrochloric acid, which has a
promotes very rapid conversion of the organic halogen to
corrosive effect. Some compounds survive fractionation and
inorganic halide. In effect this reagent solubilizes metallic
are destroyed during hydro-treating (desulfurization of the
sodium in organic compounds. The excess reagent is
naphtha).
decomposed, the mixture acidified, and the phases separated.
The aqueous phase is evaporated to 25 mL to 30 mL, acetone
5.2 Otherhalidescanalsobeusedfordewaxingcrudeoil;in
is added, and the solution titrated potentiometrically.
such cases, any organic halides will have similar impact on the
4.2.2 Procedure B, Combustion and Microcoulometry—The
refining operations as the organic chlorides.
washednaphthafractionofacrudeoilspecimenisinjectedinto
5.3 Organic chloride species are potentially damaging to
a flowing stream of gas containing about 80 % oxygen and
refinery processes. Hydrochloric acid can be produced in
20 % inert gas, such as argon, helium, or nitrogen.The gas and
hydrotreatingorreformingreactorsandtheacidaccumulatesin
sample flow through a combustion tube maintained at about
condensing regions of the refinery. Unexpected concentrations
800 °C.Thechlorineisconvertedtochlorideandoxychlorides,
of organic chlorides cannot be effectively neutralized and
which then flow into a titration cell where they react with the
damage can result. Organic chlorides are not known to be
silver ions in the titration cell. The silver ions thus consumed
naturally present in crude oils and usually result from cleaning
are coulometrically replaced. The total current required to
operationsatproducingsites,pipelines,ortanks.Itisimportant
replace the silver ions is a measure of the chlorine present in
for the oil industry to have common methods available for the
the injected samples.
determination of organic chlorides in crude oil, particularly
4.2.3 The reaction occurring in the titration cell as chloride
when transfer of custody is involved.
enters is as follows:
2 1
Cl 1Ag →AgCl ~s! (1)
6. Interferences
4.2.4 The silver ion consumed in the above reaction is
6.1 Procedure A—Other titratable halides will also give a
generated coulometrically thus:
positive response. These titratable halides include HBr and HI.
1 2
Ag°→Ag 1e (2)
6.2 Procedure B—Other titratable halides will also give a
4.2.5 These microequivalents of silver are equal to the
positive response. These titratable halides include HBr and HI
number of microequivalents of titratable sample ion entering
(HOBr and HOI do not precipitate silver). Since these oxyha-
the titration cell.
lides do not react in the titration cell, approximately 50 %
4.2.6 Procedure C, X-ray Fluorescence Spectrometry—The
microequivalent response is detected.
washed naphtha fraction of a crude oil specimen is placed in
6.2.1 This procedure is applicable in the presence of total
the X-ray beam, and the peak intensity of the chlorine Kα line
sulfur concentration of up to 10 000 times the chlorine level.
is measured by monochromatic wavelength dispersive X-ray
6.3 Procedure C—X-ray fluorescence spectrometry tech-
fluorescence (MWDXRF), monochromatic energy dispersive
niques may have interferences due to high sulfur content and
X-ray fluorescence (MEDXRF), or energy dispersive X-ray
matrix effects due to differences in the carbon-hydrogen ratio.
fluorescence (EDXRF) spectrometry. The resulting net count-
ing rate is then compared to a previously prepared calibration 6.3.1 Matrix effects result when the elemental composition
curve or equation to obtain the concentration of chlorine in (excluding chlorine) of samples differs significantly from the
mg/kg. standards, and significant errors in the chlorine determination
D4929 − 22
can result. For example, differences in the carbon-hydrogen DISTILLATION AND CLEANUP PROCEDURE
ratioofsampleandcalibrationstandardsintroduceerrorsinthe
8. Apparatus
determination.
8.1 Round-Bottom Boiling Flask, borosilicate, 1 L, single
6.3.2 In general, naphthas with compositions that vary from
short neck with 24/40 outer ground-glass joint.
white oils as specified in 28.1 can be analyzed with standards
made from base materials that are of the same or similar
8.2 Tee Adapter, borosilicate, 75° angle side-arm, 24/40
composition.Abase material for naphtha may be simulated by
ground-glass joints.
mixing isooctane and toluene in a ratio that approximates the
8.3 Thermometer,ASTMthermometer2C(–5 °Cto300 °C)
expected aromatic content of the samples to be analyzed.
or 2F, (20 °F to 580 °F).
6.3.3 Naphtha samples may contain high amounts
8.3.1 Othertemperaturemeasuringdevices,suchasthermo-
(≥0.5 mass %) of sulfur leading to significant absorption of
couples or resistance thermometers, may be used when the
chlorine Kα radiation and low chlorine results. Such samples
temperature reading obtained by these devices is determined to
can, however, be analyzed using this test method provided
produce the same naphtha fraction that is obtained when
either that the calibration standards are prepared to match the
mercury-in-glass thermometers are used.
matrix of the sample or correction factors are applied to the
8.4 Thermometer Adapter, borosilicate, 24/40 inner ground-
results. In some cases, dilution of samples with sulfur-free and
glass joint.
chlorine-free oil can be used to reduce the effect. The main
8.5 Liebig Condenser, borosilicate, 300 mm length, 24/40
disadvantage is, however, that dilution also lowers the amount
ground-glass joints.
of chlorine in the specimen. Make sure that in the diluted
specimen, the chlorine content is higher than 1 mg⁄kg before
8.6 Vacuum Take-OffAdapter,borosilicate,105°anglebend,
resorting to dilution.
24/40 ground-glass joints.
6.3.4 Matrix matching requires the knowledge of typical
8.7 ReceivingCylinder,borosilicate,250 mLcapacity,24/40
sulfur concentration in the naphtha sample and preparing
outer ground-glass joint.
calibration standards, which contain a similar sulfur concen-
8.8 Wire Clamps, for No. 24 ground-glass joints, stainless
tration. This technique is not applicable for naphtha samples
steel.
withanunknownordifferingsulfurcontentthanthecalibration
8.9 Receiver Flask, for ice bath, 4 L.
samples.
6.3.5 Sulfurcorrectionfactorsaretypicallyappliedbyusing 8.10 Copper Tubing, for heat exchanger to cool condenser
the software and algorithms supplied by the equipment vendor water, 6.4 mm outside diameter, 3 m length.
and typically uses one of the following forms: manual input of
8.11 Electric Heating Mantle, Glas-Col Series 0, 1 L size,
sulfur concentration followed by automatic correction, direct
140 W upper heating element, 380 W lower heating element.
measurement of sulfur followed by automatic correction,
8.12 Variacs, 2, for temperature control of upper and lower
correction by use of Compton scattering, and correction by
heating elements, 120 V, 10 amps.
applying fundamental parameters. Follow manufacturer’s in-
structions for application of sulfur correction factors and when
9. Reagents and Materials
to apply those factors.
9.1 Acetone, chloride-free. (Warning—Extremely
flammable, can cause flash fires. Health hazard.)
7. Purity of Reagents
9.2 Caustic Solution, 1 M potassium hydroxide
7.1 Purity of Reagents—Reagent grade chemicals shall be
(Warning—Can cause severe burns to skin.) prepared in
used in all tests. Unless otherwise indicated, it is intended that
distilled/deionized water.
all reagents shall conform to the specifications of the Commit-
9.3 Distilled/Deionized Water.
tee onAnalytical Reagents of theAmerican Chemical Society,
9.4 Filter Paper, Whatman No. 41 or equivalent.
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of 4,5
9.5 Stopcock Grease.
sufficiently high purity to permit its use without lessening the
9.6 Toluene, chloride-free. (Warning—Flammable. Health
accuracy of the determination.
hazard.)
7.2 Purity of Water—Unless otherwise indicated, references
10. Sampling
to water shall be understood to mean reagent water as defined
by Type III of Specification D1193.
10.1 ObtainatestunitinaccordancewithPracticeD4057or
D4177. To preserve volatile components, which are in some
ACS Reagent Chemicals, Specifications and Procedures for Reagents and The sole source of supply of the stop-cock grease known to the committee at
Standard-Grade Reference Materials, American Chemical Society, Washington, this time is Dow Corning silicone, available from Dow Corning Corporation,
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical Corporate Center, PO Box 994, Midland, MI.
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, If you are aware of alternative suppliers, please provide this information to
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma- ASTM International Headquarters. Your comments will receive careful consider-
copeial Convention, Inc. (USPC), Rockville, MD. ation at a meeting of the responsible technical committee, which you may attend.
D4929 − 22
samples, do not uncover samples any longer than necessary. flask to the nearest 0.1 g. Connect the flask to the distillation
Samples should be analyzed as soon as possible, after taking apparatus. Place the heating mantle around the flask, and
from bulk supplies, to prevent loss of organic chloride or support the heating mantle/flask from the bottom. Connect the
contamination due to exposure or contact with sample con- heating mantle to the variacs. Turn on the variacs and start the
tainer. (Warning—Samples that are collected at temperatures distillation. During the distillation, adjust the variac settings to
below room temperature may undergo expansion and rupture give a distillation rate of approximately 5 mL⁄min. Continue
the container. For such samples, do not fill the container to the the distillation until a thermometer reading of 204 °C (400 °F)
top; leave sufficient air space above the sample to allow room isattained.Whenthetemperaturereaches204 °C(400 °F),end
for expansion.) the distillation by first disconnecting and removing the receiv-
ing cylinder. After the receiving cylinder has been removed,
10.2 Ifthetestunitisnotusedimmediately,thenthoroughly
turn off the variacs and remove the heating mantle from the
mix in its container prior to taking a test specimen. Some test
flask. Obtain and record the mass of the receiving cylinder and
units can require heating to thoroughly homogenize.
distillate.
(Warning—When heating is required, care should be taken so
12.1.1 The precision and bias statements were determined
that no organic chloride containing hydrocarbons are lost.)
using mercury-in-glass thermometers only. Therefore, when
11. Preparation of Apparatus
alternate temperature measuring devices are used, the cut-off
temperature so obtained shall be that which will produce a
11.1 Clean all glassware by rinsing successively with tolu-
naphtha cut similar to what would be yielded when mercury-
ene and acetone.After completing the rinse, dry the glassware
in-glass thermometers are used. Such alternate temperature
using a stream of dry nitrogen gas. Obtain and record the
measuring devices shall not be expected to exhibit the same
masses of the round-bottom flask and receiving cylinder.
temperature lag characteristics as mercury-in-glass thermom-
Assembletheglassdistillationapparatususingstopcockgrease
eters.
to seal all joints and wire clamps to prevent loosening of the
joints. Adjust the thermometer position within the adapter tee
12.2 Transfer the naphtha fraction from the receiving cyl-
suchthatthelowerendofthecapillaryislevelwiththehighest inder to the separatory funnel. Using the separatory funnel,
point on the bottom of the inner wall of the adapter tee section
wash the naphtha fraction three times with equal volumes of
that connects to the condenser. the caustic solution (1 M KOH). Follow the caustic wash with
a water wash, again washing three times with equal volumes.
NOTE 1—A diagram illustrating the appropriate positioning of the
The caustic wash removes hydrogen sulfide, while the water
thermometer is found in Fig. 1 (from Test Method D86).
wash removes traces of inorganic chlorides either originally
11.2 Form the copper tubing into a coil to fit inside the
present in the crude or from impurities in the caustic solution.
receiver flask, leaving room in the center of the flask for the
After the washings are complete, filter the naphtha fraction to
receiving cylinder. With the PVC tubing, connect one end of
remove residual freestanding water. Store the naphtha fraction
the copper coil to the water source, and connect the other end
in a clean glass bottle. This naphtha fraction can now be
of the coil to the lower fitting of the Liebig condenser cooling
analyzed for organic chlorides by either sodium biphenyl,
jacket. Connect the upper condenser fitting to the water drain.
combustion/microcoulometric techniques, or X-ray fluores-
Fillthereceiverflaskwithanice/watermixture,andturnonthe
cence spectrometry.
water. Maintain the temperature of the condenser below 10 °C.
12.3 Measure the density of the crude oil specimen and the
12. Procedure
naphtha fraction by obtaining the mass of 10.0 mL (using a
12.1 Add a 500 mL crude oil test specimen to tared round 10 mL volumetric flask) of each to the nearest 0.1 g.
bottom flask. Obtain and record the mass of the crude oil-filled
13. Calculation
13.1 Calculate naphtha fraction as follows:
f 5 M /M (3)
n c
where:
f = mass fraction of naphtha collected,
M = mass of naphtha collected, and
n
M = mass of crude oil specimen.
c
13.2 Calculate the density as follows:
Density, g/mL 5 m/v (4)
where:
m = mass of sample specimen, g, and
v = volume of sample specimen, mL.
FIG. 1 Position of Thermometer in Distillation Flask
D4929 − 22
PROCEDURE A—SODIUM BIPHENYL REDUCTION 17. Procedure
AND POTENTIOMETRY
17.1 Useextremecaretopreventcontamination.Reserveall
glassware for the chloride determination. Rinse glassware with
14. Apparatus
distilled water followed by acetone just prior to use. Avoid
using chlorine-containing stopcock greases such as chlorotrif-
14.1 Electrodes—Thecleaningandpropercareofelectrodes
are critical to the accuracy of this test. Manufacturer’s instruc- luoroethylene polymer grease.
tions for the care of electrodes shall be followed.
17.2 Place 50 mL of toluene in a 250 mL separatory funnel
14.1.1 Glass, general purpose. When glass electrodes are in
and add the contents of one vial of sodium biphenyl reagent.
continuous use, weekly cleaning with chrome-sulfuric acid
Swirl to mix and add about 30 g, obtaining the mass to the
(Warning—Strong oxidizer; can cause severe burns; recog-
nearest 0.1 g of the washed naphtha fraction of crude oil
nized carcinogen), or other strongly oxidizing cleaning
sample. Obtain the mass of the sample bottle to determine the
solution, is recommended.
exact amount taken. Stopper the separatory funnel and swirl to
14.1.2 Silver-Silver Chloride, billet-type.
mix the contents thoroughly. The solution or suspension that
results should be blue-green in color. When it is not, add more
14.2 Titrator, potentiometric. The titrator is equipped with a
5 mL or smaller buret and a magnetic stirring motor. sodium biphenyl reagent (one vial at a time) until the solution
or suspension is blue-green.
15. Reagents and Materials
17.3 Allow 10 min after mixing for the reaction to be
completed, then add 2 mL of 2-propanol and swirl gently with
15.1 Acetone, chloride-free. (Warning—Extremely
the funnel unstoppered for a time until the blue-green color
flammable, can cause flash fires. Health hazard.)
changes to white, indicating that no free sodium remains.
15.2 Congo Red Paper.
Stopper the funnel and rock it gently, venting pressure fre-
15.3 2,2,4, trimethyl pentane (isooctane), reagent grade.
quently through the stopcock. Then add 20 mL of water and
(Warning—Flammable. Health hazard.)
10 mL of 5 M nitric acid. Shake gently, releasing the pressure
frequently through the stopcock. Test the aqueous phase with
15.4 Nitric Acid, approximately 5 M.(Warning—
Congoredpaper.Ifthepaperdoesnotturnblue,addadditional
Corrosive, causes severe burns.) Add 160 mL of concentrated
5Mnitricacidin5 mLportionsuntilthebluecolorisobtained.
nitric acid to about 200 mL of water and dilute to 500 mL.
17.4 Draintheaqueousphaseintoanotherseparatoryfunnel
15.5 2-Propanol, chloride-free. (Warning—Flammable.
containing 50 mL of isooctane and shake well. Drain the
Health hazard.)
aqueous phase into a 250 mL titration beaker. Make a second
15.6 Silver Nitrate, 0.01 M, standard aqueous solution.
extraction of the isooctane phase with 25 mL of water that has
5,6
15.7 Sodium Biphenyl Reagent —This is packed in 0.5 oz
been acidified with a few drops of 5 M nitric acid. Add this
French square bottles (hereafter referred to as vials).The entire
second extract to the 250 mL titration beaker. Evaporate the
contents of one vial are used for each analysis. One vial
solution on a hot plate kept just below the boiling point of the
contains 13 meq to 15 meq of active sodium. Store the sodium
liquid until 25 mL to 30 mL remains. Do not boil or evaporate
biphenyl reagent in a cool storage area, but do not refrigerate.
to less than 25 mL as loss of chloride may occur.
Prior to using, warm the reagent to approximately 50 °C and
17.5 Cool the solution and add 100 mL of acetone. Titrate
shake thoroughly to ensure a homogeneous liquid.
the solution potentiometrically with standard 0.01 M silver
15.8 Toluene,chloride-free.(Warning—Flammable.Health
nitrate, using glass versus silver-silver chloride electrodes. If
hazard.)
an automatic titrator, such as a Metrohm, is available, use the
semi-micro5 mLpistonburet.Ifthetitrationiscarriedoutwith
16. Preparation of Apparatus
a manually-operated pH meter, use a 5 mL semi-micro buret
that can be estimated to three decimal places in millilitres.
16.1 Recoating Silver-Silver Chloride Electrodes—Clean
the metal surfaces of a pair of silver-silver chloride electrodes
17.6 Determine the endpoint for the manual titration by
with mild detergent and scouring powder. Rinse the electrodes
plotting the data showing emf versus volume of silver nitrate
in distilled water. Immerse the metallic tips in saturated
solutionused.Determinetheendpointfortheautomatictitrator
potassium chloride solution. Connect one electrode to the
from the midpoint of the inflection of the titration curve.
positive pole of a 1.6 V battery and the other to the negative
17.7 Determine a blank for each group of test specimens by
pole.Reversethepolarityforseveralintervalsofafewseconds
using all of the reagents, including the sodium biphenyl, and
each to alternately clean and recoat the receptor electrode
following all the operations of the analysis except that the
(connected to the positive pole). When adequately coated, the
sample itself is omitted.
receptorelectrodetipwillturnvioletincolor.Thisresultsfrom
the action of light on the fresh silver chloride.
18. Calculation
18.1 Calculate chloride concentration in the naphtha frac-
tion as follows:
The sole source of supply of the sodium biphenyl reagent known to the
~A 2 B!~M!~35 460!
committee at this time is SouthwesternAnalytical Chemicals, P.O. Box 485,Austin,
Chloride, µg/g 5 (5)
TX. W
D4929 − 22
where: 20.2 Argon, Helium, Nitrogen, or Carbon Dioxide, high
purity grade (HP) used as the carrier gas. (Warning—These
A = volume of titrant for the sample specimen, mL,
gases are normally stored in cylinders under high pressure.
B = volume of titrant for the blank, mL,
M = molarity of silver nitrate, and These gases also dilute the oxygen content of the surrounding
W = mass of sample specimen, g. air when they leak.)
18.2 The concentration of organic chloride in the original 20.3 Cell Electrolyte Solution, 70 % acetic acid, combine
300 mL reagent water (see 7.2) with 700 mL acetic acid (see
crude oil sample specimen can be obtained by multiplying the
chloride concentration in the naphtha fraction (see 18.1)bythe 20.1) and mix well.
naphtha fraction (see 13.1).
20.4 Chloride, Standard Stock Solution, 1000 mg chloride
per litre. Accurately dispense 1.587 g of chlorobenzene into a
PROCEDURE B—COMBUSTION AND
500 mL volumetric flask and dilute to volume with 2,2,4,
MICROCOULOMETRY
trimethyl pentane (isooctane).
19. Apparatus NOTE 2—The exact concentration of chloride may be determined by
multiplying the mass of chlorobenzene by the product of the atomic mass
19.1 Combustion Furnace—The sample specimen is to be
of chlorine divided by the molecular mass of chlorobenzene and then
oxidized in an electric furnace capable of maintaining a
multiplying that result by 2000.
temperature of 800 °C to oxidize the organic matrix.
w 3m 32000
Cl mg/ L 5 (6)
~ !
m
19.2 Combustion Tube—Fabricated from quartz and con-
structedsoasample,whichisvaporizedcompletelyintheinlet
where:
section, is swept into the oxidation zone by an inert gas where
w = mass of chlorobenzene weighed,
it mixes with oxygen and is burned. The inlet end of the tube
m = atomic mass of chlorine, and
shall hold a septum for syringe entry of the sample and side
m = molecular mass of chlorobenzene.
arms for the introduction of oxygen and inert gases.The center
20.5 Chlorine, Standard Solution, 10 mg chloride per litre.
section is to be of sufficient volume to ensure complete
Pipet 1.0 mL of chloride stock solution (see 20.4) into a
oxidation of the sample.
100 mL volumetric flask and dilute to volume with 2,2,4,
19.3 Titration Cell—Containing a sensor-reference pair of
trimethyl pentane (isooctane).
electrodes to detect changes in silver ion concentration and a
20.6 Chlorobenzene, reagent grade.
generatoranode-cathodepairofelectrodestomaintainconstant
silver ion concentration and an inlet for a gaseous sample from
20.7 Gas Regulators, two-stage gas regulator must be used
the pyrolysis tube. The sensor, reference, and anode electrodes
on the reactant and carrier gas.
shall be silver electrodes. The cathode electrode shall be a
20.8 Isooctane, 2,2,4-trimethylpentane, reagent grade.
platinum wire. The reference electrode resides in a saturated
20.9 Oxygen, high purity grade, used as the reactant gas.
silver acetate half-cell. The electrolyte contains 70 % acetic
acid in water.
20.10 SilverAcetate,powderpurifiedforsaturatedreference
electrode.
19.4 Microcoulometer, having variable gain and bias
control, and capable of measuring the potential of the sensing-
21. Preparation of Apparatus
reference electrode pair, and of comparing this potential with a
bias potential, and of applying the amplified difference to the 21.1 Set up the analyzer in accordance with the equipment
working-auxiliary electrode pair so as to generate a titrant.The
manufacturer instructions.
microcoulometer output signal shall be proportional to the
21.2 The typical operational conditions are as follows:
generating current. The microcoulometer may have a digital
Reactant gas flow, O 160 mL ⁄min
meter and circuitry to convert this output signal directly to
Carrier gas flow 40 mL ⁄min
nanograms or micrograms of chloride.
Furnace temperature:
Inlet zone 700 °C
19.5 Sampling Syringe—A microlitre syringe of 50 µL ca-
Center and outlet zones 800 °C
Coulometer:
pacitycapableofaccuratelydelivering5 µLto50 µLofsample
Bias voltage, mV 240 to 265
into the pyrolysis tube.A3 in. or 6 in. (76.2 mm or 152.4 mm)
Gain ca. 1200
needle is recommended to reach the inlet zone of approxi-
21.3 Optimize the bias voltage setting for the titration cell
mately 500 °C in the combustion zone.
null-point by injecting 30 µL of chloride-free water directly
19.6 A constant rate syringe pump or manual dispensing
into the titration cell using a 6 in. needle. Adjust bias up or
adaptor may be used to facilitate slow injection of the sample
down to minimize the total integrated value due to this dilution
into the combustion tube. It is recommended that the injection
effect.
rate not exceed 0.5 µL⁄s.
22. Procedure
20. Reagents and Materials
22.1 Fill a 50 µL syringe with about 30 µL to 40 µL of the
20.1 AceticAcid, glacial acetic acid. (Warning—Corrosive, sample of washed naphtha fraction of crude oil, being careful
causes severe burns.) to eliminate bubbles.Then retract the plunger so that the lower
D4929 − 22
liquid meniscus falls on the 5 µL mark, and record the volume
C = concentration of standard, mg/L
s
of liquid in the syringe. After the sample has been injected,
23.1.2 For microcoulometers with only analog signal output
again retract the plunger so that the lower liquid meniscus falls
to a recorder the following equation applies:
on the 5 µL mark, and record the volume of liquid in the
~A!~X!~0.367!
syringe. The difference in the two volume readings is the
Chloride, µg/g 5 2 B (9)
R Y M RF
~ !~ !~ !~ !
volume of sample injected.
22.2 Alternately, obtain the sample injection device mass where:
before and after injection to determine the amount of sample
A = area in appropriate units,
injected. This method provides greater precision than the
X = recorder sensitivity for full-scale response, mV,
volume delivery method, provided a balance with a precision 0.367 =
23 6
35.45 gCl/eq 10 V/mV 10 µg/g
~ !~ !~ !
of 60.01 mg is used and the syringe is carefully handled to
~96500 coulombs/eq!
obtain repeatable weighings.
R = resistance, Ω,
22.3 Inject the sample into the pyrolysis tube at a rate not to
Y = area equivalence for a full-scale response on the
exceed 0.5 µL⁄s.
recorder per second-area units per second,
22.4 Below 5 µg⁄g, the needle-septum blank will become
M = mass of sample, g,
increasingly more obvious. To improve precision, insert the
RF = recovery factor, and
syringe needle into the hot inlet and then wait until the
B = system blank, µg/g Cl.
needle-septum blank is titrated before injecting the sample or
23.2 The concentration of organic chloride in the original
standard.
crude oil sample specimen can be obtained by multiplying the
22.5 For specimens containing more than 25 µg⁄g Cl only
chloride concentration in the naphtha fraction (see 23.1)bythe
5.0 µL of sample need be injected.
naphtha fraction (see 13.1).
22.6 Verify the system recovery, the fraction of chlorine in
PROCEDURE C—X-RAY FLUORESCENCE
the standard that is titrated, every 4 h by using the standard
SPECTROMETRY
solution(see20.5).Systemrecoveryistypically85 %orbetter.
22.7 Repeat the measurement of the calibration standard at 24. Apparatus
least three times.
24.1 Any spectrometer of the following type: Monochro-
22.8 Check the system blank daily with reagent grade matic Wavelength Dispersive X-ray Fluorescence (MWDXRF)
isooctane (see 20.8). Subtract the system blank from both
Spectrometer, Monochromatic Energy Dispersive X-ray Fluo-
sample and standard data. The system blank is typically less rescence(MEDXRF)Spectrometer,orEnergyDispersiveX-ray
than 0.2 µg⁄g chloride once the needle-septum blank has been
Fluorescence (EDXRF) Spectrometer can be used if it includes
titrated (see 22.4). the following features for its type described in this section and
the precision and bias of the test results are in accordance with
23. Calculation
the values for its type described in Section 33.(Warning—
Exposure to excessive quantities of high energy radiation such
23.1 Calculate chloride concentration in the naphtha frac-
as those produced by X-ray spectrometers is injurious to
tion as follows:
health. The operator needs to take appropriate actions to avoid
23.1.1 For microcoulometers, which read directly in nano-
exposinganypartoftheirbody,notonlytoprimaryXrays,but
grams of chloride, the following equations apply:
also to secondary or scattered radiation that might be present.
Sample Readout Blank Readout
The X-ray spectrometer should be operated in accordance with
Chloride, µg/g 5 2 (7)
V D RF V D RF
~ !~ !~ ! ~ !~ !~ !
the regulations governing the use of ionizing radiation.)
or
24.2 Monochromatic Wavelength Dispersive X-ray Fluores-
cence (MWDXRF) Spectrometer, equipped for X-ray detection
Sample Readout Blank Readout
Chloride, µg/g 5 2 (8)
at 0.473 nm (4.73 A) which also includes the following:
~M!~RF! ~M!~RF!
24.2.1 X-ray Source, capable of producing X rays to excite
where:
chlorine. X-ray tubes with a power of >20 W capable of
Readout = displayed integrated value (sample/standard/
producing Pd Lα,AgLα,TiKα,ScKα,orCrKα radiation are
blank),
recommended for this purpose.
V = volume injected µL,
24.2.2 Optical Path, designed to minimize the absorption
D = density, g/mL (12.3),
along the path of the excitation and fluorescent beams using a
RF = recovery factor, ration of chloride determined in
vacuum or a helium (see 25.6) atmosphere. If vacuum is used,
standard divided by known standard content mi-
a level of lower than 2.7 kPa (<20 Torr) is recommended. The
nus the system blank.
calibration and test measurements must be done with identical
Standard Readout Blank Readout
optical paths, including vacuum or helium pressure.
RF 5 2
V D C V D C
~ !~ !~ ! ~ !~ !~ ! 24.2.3 Incident-beam Monochromator, capable of focusing
s s
and selecting a single wavelength of characteristic X rays from
M = mass of sample specimen, mg, and
the source onto the specimen.
D4929 − 22
24.2.4 Fixed-channel Monochromator, suitable for dispers- 24.5.3 X-ray Transparent Film, for containing and support-
ing chlorine Kα X rays. ing the test specimen in the sample cell (see 24.5.2) while
providing a low{absorption window for X rays to pass to and
24.2.5 Detector, designed for efficient detection of chlorine
Kα X rays. from the sample. Any film resistant to chemical attack by the
sample,freeofchlorine,andX-raytransparentcanbeused,for
24.2.6 Single-channel Analyzer, an energy discriminator to
example, polyester, polypropylene, polycarbonate, and poly-
monitor only chlorine radiation.
imide.However,samplesofhigharomaticcontentcandissolve
24.3 MonochromaticEnergyDispersiveX-rayFluorescence
polyester and polycarbonate films.
(MEDXRF) Spectrometer, including the following:
24.5.4 Analytical Balance, for preparing calibration
24.3.1 Source of X-ray Excitation, X-ray tube withAg or Pd
standards, capable of weighing to the nearest 0.1 mg and up to
anode, in combination with HOPG Bragg monochromating
100 g.
X-ray optics. The monochromator must produce monochro-
matic Ag or Pd L radiation. Other anode materials and
25. Reagents and Materials
monochromatorsmaybeutilized,howeverstatedprecisionand
25.1 Purity of Reagents—Reagent grade chemicals shall be
bias may not apply.
used in all tests. Unless otherwise indicated, it is intended that
24.3.2 Optical Path, the system must allow flushing of the
all reagents conform to the specifications of the Committee on
optical path with helium (see 25.6).Alternatively, a vacuum of
Analytical Reagents of the American Chemical Society where
≤4.0 kPa (≤30.4 Torr) can be applied to the optical path. When
such specifications are available. Other grades may be used,
the air in the optical path is relatively small, then vacuum or
provided it is first ascertained that the reagent is of sufficiently
helium may be optional. Follow manufacturer’s recommenda-
high purity to permit its use without lessening the accuracy of
tions.
the determination.
24.3.3 X-ray Detector, with a resolution value not to exceed
25.2 Calibration Check Samples, portions of one or more
175 eV at 5.9 keV (10 000 cps). A Si drift chamber detector
liquid petroleum or product standards of known or certified
(SDD) has been found suitable for use. Using a detection
chlorine content and not used in the generation of the calibra-
system with this minimum spectral resolution has been shown
tion curve. The check samples shall be used to determine the
to eliminate the potential effect of spectral interference from
precision and accuracy of the initial calibration (see 28.6).
sulfur or other elements in the naphtha sample.
24.3.4 Signal Conditioning and Data Handling Electronics,
25.3 Chlorine Dopant (CD), a high{purity standard with a
including the functions of X-ray intensity counting, spectra
certified chlorine content. Trichloroethylene and 1,2,4-
handling by background subtraction and deconvolution, calcu-
trichlorobenzene have been found to be acceptable chlorine
lation of overlap corrections and conversion of chlorine X-ray
dopants. Use the certified chlorine concentration when calcu-
intensity into mg/kg chlorine concentration.
lating the exact concentrations of chlorine in calibration
standards.(Warning—Breathingtrichloroethylenevaporsmay
24.4 Energy Dispersive X-ray Fluorescence (EDXRF)
cause drowsiness and dizziness. Causes eye and skin irritation.
Spectrometer, required design features include:
Aspiration hazard if swallowed. Can enter lungs and cause
24.4.1 Source of X-ray Excitation, X{ray tube with excita-
damage.Maycausecancerbasedonanimalstudies.Maycause
tion energy above 2.9 keV.
liver damage.) (Warning—1,2,4-trichlorobenzene may cause
24.4.2 X-ray Detector, with high sensitivity and a resolution
respiratory tract irritation. Harmful if swallowed. Causes eye
value (Full Width at Half Maximum, FWHM) not to exceed
and skin irritation.)
175 eV at 5.9 keV (10 000 cps). A Si drift chamber detector
25.4 Counting Gas, for instruments equipped with flow
(SDD) has been found suitable for use.
proportional counters.The purity of the counting gas should be
24.4.3 Filters, or other means of discriminating between
in agreement with the specification provided by the instrument
chlorine Kα radiation and other X rays of different energy.The
manufacturer.
other means include software solutions.
24.4.4 Optical Path, the system must allow flushing of the
25.5 Drift Correction Monitor(s) (Optional)—Several dif-
optical path with helium (see 25.6).Alternatively, a vacuum of
ferent materials have been found to be suitable for use as drift
≤4.0 kPa (≤30.4 Torr) can be applied to the optical path.
correction monitors. Appropriate drift monitor samples should
24.4.5 Signal Conditioning and Data Handling Electronics,
be permanent materials that are stable with respect to repeated
that include the functions of X-ray intensity counting, a
exposure to X rays. Stable liquids, glass or metallic specimens
minimum of two energy regions, spectral overlap corrections,
are recommended. Liquids, pressed powders, and solid mate-
background corrections, and conversion of chlorine X-ray
rials that degrade with repeated exposure to X rays should not
intensity into mass percent chlorine concentration.
be used. Examples of chlorine containing materials that have
been found to be suitable include a renewable liquid petroleum
24.5 Additionally, the following apparatus is needed when
using all X-ray spectrometers within the scope of this method:
24.5.1 Display or Printer, that reads out in mg/kg chlorine.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
24.5.2 Removable Sample Cell, compatible with the sample
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
and the geometry of the XRF spectrometer.Adisposable cell is
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
recommended. The sample cell should not leak when fitted
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
with X-ray transparent film (see 24.5.3). copeial Convention, Inc. (USPC), Rockville, MD.
D4929 − 22
material, a metal alloy, or a fused glass disk. The monitor’s will affect the intensity of the chlorine X rays transmitted.
counting rate, in combination with count time, shall be Therefore, it is essential that the film be taut and clean to
sufficient to give a relative counting error of less than 1 %.The ensure reliable results.
counting rate for the monitor sample is determined during
26.3 Use the appropriate film for the sample type. Samples
calibration (see 28.4) and again at the time of analysis (see
of high aromatic content may dissolve polyester, polypropyl-
29.1). These counting rates are used to calculate a drift
ene and polycarbonate films. In these cases, other materials
correction factor (see 30.1).
besides these films may be used for X-ray windows, provided
that they do not contain any elemental impurities. Follow
NOTE 3—Calibration standards may be used as drift{monitor samples.
Because it is desirable to discard test specimens after each determination,
instrument manufacturer’s recommendations where possible.
alowercostmaterialissuggestedfordailyuse.Anystablematerialcanbe
26.4 Because impurities and thickness variations can occur
used for daily monitoring of drift.
in commercially available transparent films and vary from lot
NOTE 4—The effect of drift correction on the precision and bias of this
test method has not been studied.
to lot, use calibration-check samples (see 25.2) to verify
calibration integrity after starting each new batch of film. The
25.5.1 Drift correction is usually implemented automati-
analyzer may need recalibration if the type or thickness of the
cally in software, although the calculation can readily be done
window film is changed.
manually. For X-ray instruments that are highly stable, the
magnitude of the drift correction factor may not differ signifi-
26.5 Placethesampleinthecellusingtechniquesconsistent
cantly from unity.
with good practice for the particular instrument being used.
Although chlorine ra
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4929 − 19a D4929 − 22
Standard Test Method for
Determination of Organic Chloride Content in Crude Oil
This standard is issued under the fixed designation D4929; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 The procedures in this test method cover the determination of organic chloride (above 1 μg/g organically-bound chlorine) in
crude oils, using either distillation and sodium biphenyl reduction, distillation and microcoulometry, or distillation and X-ray
fluorescence (XRF) spectrometry.
1.2 The procedures in this test method involve the distillation of crude oil test specimens to obtain a naphtha fraction prior to
chloride determination. The chloride content of the naphtha fraction of the whole crude oil can thereby be obtained. See Section
56 regarding potential interferences.
1.3 Procedure A covers the determination of organic chloride in the washed naphtha fraction of crude oil by sodium biphenyl
reduction followed by potentiometric titration.
1.4 Procedure B covers the determination of organic chloride in the washed naphtha fraction of crude oil by oxidative combustion
followed by microcoulometric titration.
1.5 Procedure C covers the determination of organic chloride in the washed naphtha fraction of crude oil by X-ray fluorescence
spectrometry.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6.1 The preferred concentration units are micrograms of chloride per gram of sample, though milligrams of chloride per
kilogram of sample is commonly used for Procedure C.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.03 on Elemental Analysis.
Current edition approved Dec. 1, 2019Oct. 1, 2022. Published December 2019October 2022. Originally approved in 1989. Last previous edition approved in 2019 as
D4929 – 19.D4929 – 19a. DOI: 10.1520/D4929-19A.10.1520/D4929-22.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4929 − 22
2. Referenced Documents
2.1 ASTM Standards:
D86 Test Method for Distillation of Petroleum Products and Liquid Fuels at Atmospheric Pressure
D1193 Specification for Reagent Water
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport
to Measure the Same Property of a Material
D7343 Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methods
for Elemental Analysis of Petroleum Products and Lubricants
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 naphtha fraction, n—the fraction of the crude oil collected from atmospheric distillation over a boiling range up to 204 °C.
3.2.2 organic chloride compounds, n—compounds containing carbon and at least one chlorine.
3.2.3 total organic chloride compounds, n—the sum of compounds containing carbon and at least one chlorine.
4. Summary of Test Method
4.1 A crude oil distillation is performed to obtain the naphtha cut at 204 °C (400 °F). The distillation method was adapted from
Test Method D86 for the distillation of petroleum products. The naphtha cut is washed with caustic, repeatedly when necessary,
until all hydrogen sulfide is removed. The naphtha cut, free of hydrogen sulfide, is then washed with water, repeatedly when
necessary, to remove inorganic halides (chlorides).
4.2 There are three alternative procedures for determination of the organic chloride in the washed naphtha fraction, as follows.
4.2.1 Procedure A, Sodium Biphenyl Reduction and Potentiometry—The washed naphtha fraction of a crude oil specimen is
weighed and transferred to a separatory funnel containing sodium biphenyl reagent in toluene. The reagent is an addition
compound of sodium and biphenyl in ethylene glycol dimethyl ether. The free radical nature of this reagent promotes very rapid
conversion of the organic halogen to inorganic halide. In effect this reagent solubilizes metallic sodium in organic compounds. The
excess reagent is decomposed, the mixture acidified, and the phases separated. The aqueous phase is evaporated to 25 mL to
30 mL, acetone is added, and the solution titrated potentiometrically.
4.2.2 Procedure B, Combustion and Microcoulometry—The washed naphtha fraction of a crude oil specimen is injected into a
flowing stream of gas containing about 80 % oxygen and 20 % inert gas, such as argon, helium, or nitrogen. The gas and sample
flow through a combustion tube maintained at about 800 °C. The chlorine is converted to chloride and oxychlorides, which then
flow into a titration cell where they react with the silver ions in the titration cell. The silver ions thus consumed are coulometrically
replaced. The total current required to replace the silver ions is a measure of the chlorine present in the injected samples.
4.2.3 The reaction occurring in the titration cell as chloride enters is as follows:
2 1
Cl 1Ag →AgCl ~s! (1)
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D4929 − 22
4.2.4 The silver ion consumed in the above reaction is generated coulometrically thus:
1 2
Ag°→Ag 1e (2)
4.2.5 These microequivalents of silver are equal to the number of microequivalents of titratable sample ion entering the titration
cell.
4.2.6 Procedure C, X-ray Fluorescence Spectrometry—The washed naphtha fraction of a crude oil specimen is placed in the X-ray
beam, and the peak intensity of the chlorine Kα line is measured by monochromatic wavelength dispersive X-ray fluorescence
(MWDXRF), monochromatic energy dispersive X-ray fluorescence (MEDXRF), or energy dispersive X-ray fluorescence
(EDXRF) spectrometry. The resulting net counting rate is then compared to a previously prepared calibration curve or equation
to obtain the concentration of chlorine in mg/kg.
5. Significance and Use
5.1 Organic chlorides do not occur naturally in crude oil. When present, they result from contamination in some manner, such as
disposal of chlorinated solvent used in many dewaxing pipeline or other equipment operations.
5.1.1 Uncontaminated crude oil will contain no detectable organic chloride, and most refineries can handle very small amounts
without deleterious effects.
5.1.1.1 Most trade contracts specify that no organic chloride is present in the crude oil.
5.1.2 Several pipelines have set specification limits at <1 mg ⁄kg organic chlorides in the whole crude, and <5 mg ⁄kg in the light
naphtha, on the basis of the naphtha fraction being 20 % of the original sample.
5.1.2.1 To ensure <1 mg ⁄kg organic chloride in the crude oil, the amount measured in the naphtha fraction shall be <1/f (where
f is the naphtha fraction calculated with Eq 3).
5.1.3 Organic chloride present in the crude oil (for example, methylene chloride, perchloroethylene, etc.) is usually distilled into
the naphtha fraction. Some compounds break down during fractionation and produce hydrochloric acid, which has a corrosive
effect. Some compounds survive fractionation and are destroyed during hydro-treating (desulfurization of the naphtha).
5.2 Other halides can also be used for dewaxing crude oil; in such cases, any organic halides will have similar impact on the
refining operations as the organic chlorides.
5.3 Organic chloride species are potentially damaging to refinery processes. Hydrochloric acid can be produced in hydrotreating
or reforming reactors and the acid accumulates in condensing regions of the refinery. Unexpected concentrations of organic
chlorides cannot be effectively neutralized and damage can result. Organic chlorides are not known to be naturally present in crude
oils and usually result from cleaning operations at producing sites, pipelines, or tanks. It is important for the oil industry to have
common methods available for the determination of organic chlorides in crude oil, particularly when transfer of custody is
involved.
6. Interferences
6.1 Procedure A—Other titratable halides will also give a positive response. These titratable halides include HBr and HI.
6.2 Procedure B—Other titratable halides will also give a positive response. These titratable halides include HBr and HI (HOBr
and HOI do not precipitate silver). Since these oxyhalides do not react in the titration cell, approximately 50 % microequivalent
response is detected.
6.2.1 This procedure is applicable in the presence of total sulfur concentration of up to 10 000 times the chlorine level.
6.3 Procedure C—X-ray fluorescence spectrometry techniques may have interferences due to high sulfur content and matrix
effects due to differences in the carbon-hydrogen ratio.
D4929 − 22
6.3.1 Matrix effects result when the elemental composition (excluding chlorine) of samples differs significantly from the standards,
and significant errors in the chlorine determination can result. For example, differences in the carbon-hydrogen ratio of sample and
calibration standards introduce errors in the determination.
6.3.2 In general, naphthas with compositions that vary from white oils as specified in 27.128.1 can be analyzed with standards
made from base materials that are of the same or similar composition. A base material for naphtha may be simulated by mixing
isooctane and toluene in a ratio that approximates the expected aromatic content of the samples to be analyzed.
6.3.3 Naphtha samples may contain high amounts (≥0.5 mass %) of sulfur leading to significant absorption of chlorine Kα
radiation and low chlorine results. Such samples can, however, be analyzed using this test method provided either that the
calibration standards are prepared to match the matrix of the sample or correction factors are applied to the results. In some cases,
dilution of samples with sulfur-free and chlorine-free oil can be used to reduce the effect. The main disadvantage is, however, that
dilution also lowers the amount of chlorine in the specimen. Make sure that in the diluted specimen, the chlorine content is higher
than 1 mg ⁄kg before resorting to dilution.
6.3.4 Matrix matching requires the knowledge of typical sulfur concentration in the naphtha sample and preparing calibration
standards, which contain a similar sulfur concentration. This technique is not applicable for naphtha samples with an unknown or
differing sulfur content than the calibration samples.
6.3.5 Sulfur correction factors are typically applied by using the software and algorithms supplied by the equipment vendor and
typically uses one of the following forms: manual input of sulfur concentration followed by automatic correction, direct
measurement of sulfur followed by automatic correction, correction by use of Compton scattering, and correction by applying
fundamental parameters. Follow manufacturer’s instructions for application of sulfur correction factors and when to apply those
factors.
7. Purity of Reagents
7.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by Type
III of Specification D1193.
DISTILLATION AND CLEANUP PROCEDURE
8. Apparatus
8.1 Round-Bottom Boiling Flask, borosilicate, 1 L, single short neck with 24/40 outer ground-glass joint.
8.2 Tee Adapter, borosilicate, 75° angle side-arm, 24/40 ground-glass joints.
8.3 Thermometer, ASTM thermometer 2C (–5 °C to 300 °C) or 2F, (20 °F to 580 °F).
8.3.1 Other temperature measuring devices, such as thermocouples or resistance thermometers, may be used when the temperature
reading obtained by these devices is determined to produce the same naphtha fraction that is obtained when mercury-in-glass
thermometers are used.
8.4 Thermometer Adapter, borosilicate, 24/40 inner ground-glass joint.
8.5 Liebig Condenser, borosilicate, 300 mm length, 24/40 ground-glass joints.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference Materials, American Chemical Society, Washington, DC. For
suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and
the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D4929 − 22
8.6 Vacuum Take-Off Adapter, borosilicate, 105° angle bend, 24/40 ground-glass joints.
8.7 Receiving Cylinder, borosilicate, 250 mL capacity, 24/40 outer ground-glass joint.
8.8 Wire Clamps, for No. 24 ground-glass joints, stainless steel.
8.9 Receiver Flask, for ice bath, 4 L.
8.10 Copper Tubing, for heat exchanger to cool condenser water, 6.4 mm outside diameter, 3 m length.
8.11 Electric Heating Mantle, Glas-Col Series 0, 1 L size, 140 W upper heating element, 380 W lower heating element.
8.12 Variacs, 2, for temperature control of upper and lower heating elements, 120 V, 10 amps.
9. Reagents and Materials
9.1 Acetone, chloride-free. (Warning—Extremely flammable, can cause flash fires. Health hazard.)
9.2 Caustic Solution, 1 M potassium hydroxide (Warning—Can cause severe burns to skin.) prepared in distilled/deionized water.
9.3 Distilled/Deionized Water.
9.4 Filter Paper, Whatman No. 41 or equivalent.
4,5
9.5 Stopcock Grease.
9.6 Toluene, chloride-free. (Warning—Flammable. Health hazard.)
10. Sampling
10.1 Obtain a test unit in accordance with Practice D4057 or D4177. To preserve volatile components, which are in some samples,
do not uncover samples any longer than necessary. Samples should be analyzed as soon as possible, after taking from bulk supplies,
to prevent loss of organic chloride or contamination due to exposure or contact with sample container. (Warning—Samples that
are collected at temperatures below room temperature may undergo expansion and rupture the container. For such samples, do not
fill the container to the top; leave sufficient air space above the sample to allow room for expansion.)
10.2 If the test unit is not used immediately, then thoroughly mix in its container prior to taking a test specimen. Some test units
can require heating to thoroughly homogenize. (Warning—When heating is required, care should be taken so that no organic
chloride containing hydrocarbons are lost.)
11. Preparation of Apparatus
11.1 Clean all glassware by rinsing successively with toluene and acetone. After completing the rinse, dry the glassware using a
stream of dry nitrogen gas. Obtain and record the masses of the round-bottom flask and receiving cylinder. Assemble the glass
distillation apparatus using stopcock grease to seal all joints and wire clamps to prevent loosening of the joints. Adjust the
thermometer position within the adapter tee such that the lower end of the capillary is level with the highest point on the bottom
of the inner wall of the adapter tee section that connects to the condenser.
The sole source of supply of the stop-cock grease known to the committee at this time is Dow Corning silicone, available from Dow Corning Corporation, Corporate
Center, PO Box 994, Midland, MI.
If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
D4929 − 22
NOTE 1—A diagram illustrating the appropriate positioning of the thermometer can be is found in Fig. 1 (from Test Method D86.).
11.2 Form the copper tubing into a coil to fit inside the receiver flask, leaving room in the center of the flask for the receiving
cylinder. With the PVC tubing, connect one end of the copper coil to the water source, and connect the other end of the coil to
the lower fitting of the Liebig condenser cooling jacket. Connect the upper condenser fitting to the water drain. Fill the receiver
flask with an ice/water mixture, and turn on the water. Maintain the temperature of the condenser below 10 °C.
12. Procedure
12.1 Add a 500 mL crude oil test specimen to tared round bottom flask. Obtain and record the mass of the crude oil-filled flask
to the nearest 0.1 g. Connect the flask to the distillation apparatus. Place the heating mantle around the flask, and support the
heating mantle/flask from the bottom. Connect the heating mantle to the variacs. Turn on the variacs and start the distillation.
During the distillation, adjust the variac settings to give a distillation rate of approximately 5 mL ⁄min. Continue the distillation
until a thermometer reading of 204 °C (400 °F) is attained. When the temperature reaches 204 °C (400 °F), end the distillation by
first disconnecting and removing the receiving cylinder. After the receiving cylinder has been removed, turn off the variacs and
remove the heating mantle from the flask. Obtain and record the mass of the receiving cylinder and distillate.
12.1.1 The precision and bias statements were determined using mercury-in-glass thermometers only. Therefore, when alternate
temperature measuring devices are used, the cut-off temperature so obtained shall be that which will produce a naphtha cut similar
to what would be yielded when mercury-in-glass thermometers are used. Such alternate temperature measuring devices shall not
be expected to exhibit the same temperature lag characteristics as mercury-in-glass thermometers.
12.2 Transfer the naphtha fraction from the receiving cylinder to the separatory funnel. Using the separatory funnel, wash the
naphtha fraction three times with equal volumes of the caustic solution (1 M KOH). Follow the caustic wash with a water wash,
again washing three times with equal volumes. The caustic wash removes hydrogen sulfide, while the water wash removes traces
of inorganic chlorides either originally present in the crude or from impurities in the caustic solution. After the washings are
complete, filter the naphtha fraction to remove residual freestanding water. Store the naphtha fraction in a clean glass bottle. This
naphtha fraction can now be analyzed for organic chlorides by either sodium biphenyl, combustion/microcoulometric techniques,
or X-ray fluorescence spectrometry.
12.3 Measure the density of the crude oil specimen and the naphtha fraction by obtaining the mass of 10.0 mL (using a 10 mL
volumetric flask) of each to the nearest 0.1 g.
13. Calculation
13.1 Calculate naphtha fraction as follows:
f 5 M /M (3)
n c
where:
f = mass fraction of naphtha collected,
M = mass of naphtha collected, and
n
FIG. 1 Position of Thermometer in Distillation Flask
D4929 − 22
M = mass of crude oil specimen.
c
13.2 Calculate the density as follows:
Density, g/mL 5 m/v (4)
where:
m = mass of sample specimen, g, and
v = volume of sample specimen, mL.
PROCEDURE A—SODIUM BIPHENYL REDUCTION AND POTENTIOMETRY
14. Apparatus
14.1 Electrodes—The cleaning and proper care of electrodes are critical to the accuracy of this test. Manufacturer’s instructions
for the care of electrodes shall be followed.
14.1.1 Glass, general purpose. When glass electrodes are in continuous use, weekly cleaning with chrome-sulfuric acid
(Warning—Strong oxidizer; can cause severe burns; recognized carcinogen), or other strongly oxidizing cleaning solution, is
recommended.
14.1.2 Silver-Silver Chloride, billet-type.
14.2 Titrator, potentiometric. The titrator is equipped with a 5 mL or smaller buret and a magnetic stirring motor.
15. Reagents and Materials
15.1 Acetone, chloride-free. (Warning—Extremely flammable, can cause flash fires. Health hazard.)
15.2 Congo Red Paper.
15.3 2,2,4, trimethyl pentane (isooctane), reagent grade. (Warning—Flammable. Health hazard.)
15.4 Nitric Acid, approximately 5 M. (Warning—Corrosive, causes severe burns.) Add 160 mL of concentrated nitric acid to
about 200 mL of water and dilute to 500 mL.
15.5 2-Propanol, chloride-free. (Warning—Flammable. Health hazard.)
15.6 Silver Nitrate, 0.01 M, standard aqueous solution.
5,6
15.7 Sodium Biphenyl Reagent —This is packed in 0.5 oz French square bottles (hereafter referred to as vials). The entire
contents of one vial are used for each analysis. One vial contains 13 meq to 15 meq of active sodium. Store the sodium biphenyl
reagent in a cool storage area, but do not refrigerate. Prior to using, warm the reagent to approximately 50 °C and shake thoroughly
to ensure a homogeneous liquid.
15.8 Toluene, chloride-free. (Warning—Flammable. Health hazard.)
16. Preparation of Apparatus
16.1 Recoating Silver-Silver Chloride Electrodes—Clean the metal surfaces of a pair of silver-silver chloride electrodes with mild
detergent and scouring powder. Rinse the electrodes in distilled water. Immerse the metallic tips in saturated potassium chloride
solution. Connect one electrode to the positive pole of a 1.6 V battery and the other to the negative pole. Reverse the polarity for
The sole source of supply of the sodium biphenyl reagent known to the committee at this time is Southwestern Analytical Chemicals, P.O. Box 485, Austin, TX.
D4929 − 22
several intervals of a few seconds each to alternately clean and recoat the receptor electrode (connected to the positive pole). When
adequately coated, the receptor electrode tip will turn violet in color. This results from the action of light on the fresh silver
chloride.
17. Procedure
17.1 Use extreme care to prevent contamination. Reserve all glassware for the chloride determination. Rinse glassware with
distilled water followed by acetone just prior to use. Avoid using chlorine-containing stopcock greases such as chlorotrifluoro-
ethylene polymer grease.
17.2 Place 50 mL of toluene in a 250 mL separatory funnel and add the contents of one vial of sodium biphenyl reagent. Swirl
to mix and add about 30 g, obtaining the mass to the nearest 0.1 g of the washed naphtha fraction of crude oil sample. Obtain the
mass of the sample bottle to determine the exact amount taken. Stopper the separatory funnel and swirl to mix the contents
thoroughly. The solution or suspension that results should be blue-green in color. When it is not, add more sodium biphenyl reagent
(one vial at a time) until the solution or suspension is blue-green.
17.3 Allow 10 min after mixing for the reaction to be completed, then add 2 mL of 2-propanol and swirl gently with the funnel
unstoppered for a time until the blue-green color changes to white, indicating that no free sodium remains. Stopper the funnel and
rock it gently, venting pressure frequently through the stopcock. Then add 20 mL of water and 10 mL of 5 M nitric acid. Shake
gently, releasing the pressure frequently through the stopcock. Test the aqueous phase with Congo red paper. If the paper does not
turn blue, add additional 5 M nitric acid in 5 mL portions until the blue color is obtained.
17.4 Drain the aqueous phase into another separatory funnel containing 50 mL of isooctane and shake well. Drain the aqueous
phase into a 250 mL titration beaker. Make a second extraction of the isooctane phase with 25 mL of water that has been acidified
with a few drops of 5 M nitric acid. Add this second extract to the 250 mL titration beaker. Evaporate the solution on a hot plate
kept just below the boiling point of the liquid until 25 mL to 30 mL remains. Do not boil or evaporate to less than 25 mL as loss
of chloride may occur.
17.5 Cool the solution and add 100 mL of acetone. Titrate the solution potentiometrically with standard 0.01 M silver nitrate, using
glass versus silver-silver chloride electrodes. If an automatic titrator, such as a Metrohm, is available, use the semi-micro 5 mL
piston buret. If the titration is carried out with a manually-operated pH meter, use a 5 mL semi-micro buret that can be estimated
to three decimal places in millilitres.
17.6 Determine the endpoint for the manual titration by plotting the data showing emf versus volume of silver nitrate solution
used. Determine the endpoint for the automatic titrator from the midpoint of the inflection of the titration curve.
17.7 Determine a blank for each group of test specimens by using all of the reagents, including the sodium biphenyl, and following
all the operations of the analysis except that the sample itself is omitted.
18. Calculation
18.1 Calculate chloride concentration in the naphtha fraction as follows:
~A 2 B! ~M! ~35 460!
Chloride, µg/g5 (5)
W
where:
A = volume of titrant for the sample specimen, mL,
B = volume of titrant for the blank, mL,
M = molarity of silver nitrate, and
W = mass of sample specimen, g.
18.2 The concentration of organic chloride in the original crude oil sample specimen can be obtained by multiplying the chloride
concentration in the naphtha fraction (see 17.118.1) by the naphtha fraction (see 12.113.1).
D4929 − 22
PROCEDURE B—COMBUSTION AND MICROCOULOMETRY
19. Apparatus
19.1 Combustion Furnace—The sample specimen is to be oxidized in an electric furnace capable of maintaining a temperature
of 800 °C to oxidize the organic matrix.
19.2 Combustion Tube—Fabricated from quartz and constructed so a sample, which is vaporized completely in the inlet section,
is swept into the oxidation zone by an inert gas where it mixes with oxygen and is burned. The inlet end of the tube shall hold
a septum for syringe entry of the sample and side arms for the introduction of oxygen and inert gases. The center section is to be
of sufficient volume to ensure complete oxidation of the sample.
19.3 Titration Cell—Containing a sensor-reference pair of electrodes to detect changes in silver ion concentration and a generator
anode-cathode pair of electrodes to maintain constant silver ion concentration and an inlet for a gaseous sample from the pyrolysis
tube. The sensor, reference, and anode electrodes shall be silver electrodes. The cathode electrode shall be a platinum wire. The
reference electrode resides in a saturated silver acetate half-cell. The electrolyte contains 70 % acetic acid in water.
19.4 Microcoulometer, having variable gain and bias control, and capable of measuring the potential of the sensing-reference
electrode pair, and of comparing this potential with a bias potential, and of applying the amplified difference to the
working-auxiliary electrode pair so as to generate a titrant. The microcoulometer output signal shall be proportional to the
generating current. The microcoulometer may have a digital meter and circuitry to convert this output signal directly to nanograms
or micrograms of chloride.
19.5 Sampling Syringe—A microlitre syringe of 50 μL capacity capable of accurately delivering 5 μL to 50 μL of sample into the
pyrolysis tube. A 3 in. or 6 in. (76.2 mm or 152.4 mm) needle is recommended to reach the inlet zone of approximately 500 °C
in the combustion zone.
19.6 A constant rate syringe pump or manual dispensing adaptor may be used to facilitate slow injection of the sample into the
combustion tube. It is recommended that the injection rate not exceed 0.5 μL ⁄s.
20. Reagents and Materials
20.1 Acetic Acid, glacial acetic acid. (Warning—Corrosive, causes severe burns.)
20.2 Argon, Helium, Nitrogen, or Carbon Dioxide, high purity grade (HP) used as the carrier gas. (Warning—These gases are
normally stored in cylinders under high pressure. These gases also dilute the oxygen content of the surrounding air when they leak.)
20.3 Cell Electrolyte Solution, 70 % acetic acid, combine 300 mL reagent water (see 6.27.2) with 700 mL acetic acid (see
19.120.1) and mix well.
20.4 Chloride, Standard Stock Solution, 1000 mg chloride per litre. Accurately dispense 1.587 g of chlorobenzene into a 500 mL
volumetric flask and dilute to volume with 2,2,4,trimethyl pentane (isooctane).
NOTE 2—The exact concentration of chloride may be determined by multiplying the mass of chlorobenzene by the product of the atomic mass of chlorine
divided by the molecular mass of chlorobenzene and then multiplying that result by 2000.
w 3m 32000
Cl ~mg/ L!5 (6)
m
where:
w = mass of chlorobenzene weighed,
m = atomic mass of chlorine, and
m = molecular mass of chlorobenzene.
D4929 − 22
20.5 Chlorine, Standard Solution, 10 mg chloride per litre. Pipet 1.0 mL of chloride stock solution (see 19.420.4) into a 100 mL
volumetric flask and dilute to volume with 2,2,4,trimethyl pentane (isooctane).
20.6 Chlorobenzene, reagent grade.
20.7 Gas Regulators, two-stage gas regulator must be used on the reactant and carrier gas.
20.8 Isooctane, 2,2,4-trimethylpentane, reagent grade.
20.9 Oxygen, high purity grade, used as the reactant gas.
20.10 Silver Acetate, powder purified for saturated reference electrode.
21. Preparation of Apparatus
21.1 Set up the analyzer in accordance with the equipment manufacturer instructions.
21.2 The typical operational conditions are as follows:
Reactant gas flow, O 160 mL ⁄min
Carrier gas flow 40 mL ⁄min
Furnace temperature:
Inlet zone 700 °C
Center and outlet zones 800 °C
Coulometer:
Bias voltage, mV 240 to 265
Gain ca. 1200
21.3 Optimize the bias voltage setting for the titration cell null-point by injecting 30 μL of chloride-free water directly into the
titration cell using a 6 in. needle. Adjust bias up or down to minimize the total integrated value due to this dilution effect.
22. Procedure
22.1 Fill a 50 μL syringe with about 30 μL to 40 μL of the sample of washed naphtha fraction of crude oil, being careful to
eliminate bubbles. Then retract the plunger so that the lower liquid meniscus falls on the 5 μL mark, and record the volume of liquid
in the syringe. After the sample has been injected, again retract the plunger so that the lower liquid meniscus falls on the 5 μL mark,
and record the volume of liquid in the syringe. The difference in the two volume readings is the volume of sample injected.
22.2 Alternately, obtain the sample injection device mass before and after injection to determine the amount of sample injected.
This method provides greater precision than the volume delivery method, provided a balance with a precision of 60.01 mg is used
and the syringe is carefully handled to obtain repeatable weighings.
22.3 Inject the sample into the pyrolysis tube at a rate not to exceed 0.5 μL ⁄s.
22.4 Below 5 μg ⁄g, the needle-septum blank will become increasingly more obvious. To improve precision, insert the syringe
needle into the hot inlet and then wait until the needle-septum blank is titrated before injecting the sample or standard.
22.5 For specimens containing more than 25 μg ⁄g Cl only 5.0 μL of sample need be injected.
22.6 Verify the system recovery, the fraction of chlorine in the standard that is titrated, every 4 h by using the standard solution
(see 19.520.5). System recovery is typically 85 % or better.
22.7 Repeat the measurement of the calibration standard at least three times.
D4929 − 22
22.8 Check the system blank daily with reagent grade isooctane (see 19.820.8). Subtract the system blank from both sample and
standard data. The system blank is typically less than 0.2 μg ⁄g chloride once the needle-septum blank has been titrated (see
21.422.4).
23. Calculation
23.1 Calculate chloride concentration in the naphtha fraction as follows:
23.1.1 For microcoulometers, which read directly in nanograms of chloride, the following equations apply:
Sample Readout Blank Readout
Chloride, µg/g5 2 (7)
~V! ~D! ~RF! ~V! ~D! ~RF!
or
Sample Readout Blank Readout
Chloride, µg/g5 2 (8)
M RF M RF
~ ! ~ ! ~ ! ~ !
where:
Readout = displayed integrated value (sample/standard/ blank),
V = volume injected μL,
D = density, g/mL (11.3),
D = density, g/mL (12.3),
RF = recovery factor, ration of chloride determined in standard divided by known standard content minus the system blank.
Standard Readout Blank Readout
RF 5 2
V D C V D C
~ ! ~ ! ~ ! ~ ! ~ ! ~ !
s s
M = mass of sample specimen, mg, and
C = concentration of standard, mg/L
s
23.1.2 For microcoulometers with only analog signal output to a recorder the following equation applies:
~A! ~X! ~0.367!
Chloride, µg/g5 2 B (9)
R Y M RF
~ ! ~ ! ~ ! ~ !
where:
A = area in appropriate units,
X = recorder sensitivity for full-scale response, mV,
0.367 =
23 6
~35.45 gCl/eq! ~10 V/mV! ~10 µg/g!
96 500 coulombs/eq
~ !
R = resistance, Ω,
Y = area equivalence for a full-scale response on the recorder per second-area units per second,
M = mass of sample, g,
RF = recovery factor, and
B = system blank, μg/g Cl.
23.2 The concentration of organic chloride in the original crude oil sample specimen can be obtained by multiplying the chloride
concentration in the naphtha fraction (see 22.123.1) by the naphtha fraction (see 12.113.1).
PROCEDURE C—X-RAY FLUORESCENCE SPECTROMETRY
24. Apparatus
24.1 Any spectrometer of the following type: Monochromatic Wavelength Dispersive X-ray Fluorescence (MWDXRF)
Spectrometer, Monochromatic Energy Dispersive X-ray Fluorescence (MEDXRF) Spectrometer, or Energy Dispersive X-ray
Fluorescence (EDXRF) Spectrometer can be used if it includes the following features for its type described in this section and the
D4929 − 22
precision and bias of the test results are in accordance with the values for its type described in Section 3233. (Warning—Exposure
to excessive quantities of high energy radiation such as those produced by X-ray spectrometers is injurious to health. The operator
needs to take appropriate actions to avoid exposing any part of their body, not only to primary X-rays, X rays, but also to secondary
or scattered radiation that might be present. The X-ray spectrometer should be operated in accordance with the regulations
governing the use of ionizing radiation.)
24.2 Monochromatic Wavelength Dispersive X-ray Fluorescence (MWDXRF) Spectrometer, equipped for X-ray detection at
0.473 nm (4.73 A) which also includes the following:
24.2.1 X-ray Source, capable of producing X-rays X rays to excite chlorine. X-ray tubes with a power of >20 W capable of
producing Pd Lα, Ag Lα, Ti Kα, Sc Kα, or Cr Kα radiation are recommended for this purpose.
24.2.2 Optical Path, designed to minimize the absorption along the path of the excitation and fluorescent beams using a vacuum
or a helium (see 24.625.6) atmosphere. If vacuum is used, a level of lower than 2.7 kPa (<20 Torr) is recommended. The calibration
and test measurements must be done with identical optical paths, including vacuum or helium pressure.
24.2.3 Incident-beam Monochromator, capable of focusing and selecting a single wavelength of characteristic X-rays X rays from
the source onto the specimen.
24.2.4 Fixed-channel Monochromator, suitable for dispersing chlorine Kα X-rays.X rays.
24.2.5 Detector, designed for efficient detection of chlorine Kα X-rays.X rays.
24.2.6 Single-channel Analyzer, an energy discriminator to monitor only chlorine radiation.
24.3 Monochromatic Energy Dispersive X-ray Fluorescence (MEDXRF) Spectrometer, including the following:
24.3.1 Source of X-ray Excitation, X-ray tube with Ag or Pd anode, in combination with HOPG Bragg monochromating X-ray
optics. The monochromator must produce monochromatic Ag or Pd L radiation. Other anode materials and monochromators may
be utilized, however stated precision and bias may not apply.
24.3.2 Optical Path, the system must allow flushing of the optical path with helium (see 24.625.6). Alternatively, a vacuum of
≤4.0 kPa (≤30.4 Torr) can be applied to the optical path. When the air in the optical path is relatively small, then vacuum or helium
may be optional. Follow manufacturer’s recommendations.
24.3.3 X-ray Detector, with a resolution value not to exceed 175 eV at 5.9 keV (10 000 cps). A Si drift chamber detector (SDD)
has been found suitable for use. Using a detection system with this minimum spectral resolution has been shown to eliminate the
potential effect of spectral interference from sulfur or other elements in the naphtha sample.
24.3.4 Signal Conditioning and Data Handling Electronics, including the functions of X-ray intensity counting, spectra handling
by background subtraction and deconvolution, calculation of overlap corrections and conversion of chlorine X-ray intensity into
mg/kg chlorine concentration.
24.4 Energy Dispersive X-ray Fluorescence (EDXRF) Spectrometer, required design features include:
24.4.1 Source of X-ray Excitation, X{ray tube with excitation energy above 2.9 keV.
24.4.2 X-ray Detector, with high sensitivity and a resolution value (Full Width at Half Maximum, FWHM) not to exceed 175 eV
at 5.9 keV (10 000 cps). A Si drift chamber detector (SDD) has been found suitable for use.
24.4.3 Filters, or other means of discriminating between chlorine Kα radiation and other X-rays X rays of different energy. The
other means include software solutions.
24.4.4 Optical Path, the system must allow flushing of the optical path with helium (see 24.625.6). Alternatively, a vacuum of
≤4.0 kPa (≤30.4 Torr) can be applied to the optical path.
D4929 − 22
24.4.5 Signal Conditioning and Data Handling Electronics, that include the functions of X-ray intensity counting, a minimum of
two energy regions, spectral overlap corrections, background corrections, and conversion of chlorine X-ray intensity into mass
percent chlorine concentration.
24.5 Additionally, the following apparatus is needed when using all x{rayX-ray spectrometers within the scope of this method:
24.5.1 Display or Printer, that reads out in mg/kg chlorine.
24.5.2 Removable Sample Cell, compatible with the sample and the geometry of the XRF spectrometer. A disposable cell is
recommended. The sample cell should not leak when fitted with X-ray transparent film (see 23.5.324.5.3).
24.5.3 X-ray Transparent Film, for containing and supporting the test specimen in the sample cell (see 23.5.224.5.2) while
providing a low{absorption window for X-rays X rays to pass to and from the sample. Any film resistant to chemical attack by
the sample, free of chlorine, and X-ray transparent can be used, for example, polyester, polypropylene, polycarbonate, and
polyimide. However, samples of high aromatic content can dissolve polyester and polycarbonate films.
24.5.4 Analytical Balance, for preparing calibration standards, capable of weighing to the nearest 0.1 mg and up to 100 g.
25. Reagents and Materials
25.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity
to permit its use without lessening the accuracy of the determination.
25.2 Calibration Check Samples, portions of one or more liquid petroleum or product standards of known or certified chlorine
content and not used in the generation of the calibration curve. The check samples shall be used to determine the precision and
accuracy of the initial calibration (see 27.628.6).
25.3 Chlorine Dopant (CD), a high{purity standard with a certified chlorine content. Trichloroethylene and 1,2,4-trichlorobenzene
have been found to be acceptable chlorine dopants. Use the certified chlorine concentration when calculating the exact
concentrations of chlorine in calibration standards. (Warning—Breathing trichloroethylene vapors may cause drowsiness and
dizziness. Causes eye and skin irritation. Aspiration hazard if swallowed. Can enter lungs and cause damage. May cause cancer
based on animal studies. May cause liver damage.) (Warning—1,2,4-trichlorobenzene may cause respiratory tract irritation.
Harmful if swallowed. Causes eye and skin irritation.)
25.4 Counting Gas, for instruments equipped with flow proportional counters. The purity of the counting gas should be in
agreement with the specification provided by the instrument manufacturer.
25.5 Drift Correction Monitor(s) (Optional)—Several different materials have been found to be suitable for use as drift correction
monitors. Appropriate drift monitor samples should be permanent materials that are stable with respect to repeated exposure to
X-rays. X rays. Stable liquids, glass or metallic specimens are recommended. Liquids, pressed powders, and solid materials that
degrade with repeated exposure to X-rays X rays should not be used. Examples of chlorine containing materials that have been
found to be suitable include a renewable liquid petroleum material, a metal alloy, or a fused glass disk. The monitor’s counting
rate, in combination with count time, shall be sufficient to give a relative counting error of less than 1 %. The counting rate for
the monitor sample is determined during calibration (see 27.428.4) and again at the time of analysis (see 28.129.1). These counting
rates are used to calculate a drift correction factor (see 29.130.1).
NOTE 3—Calibration standards may be used as drift{monitor samples. Because it is desirable to discard test specimens after each determination, a lower
cost material is suggested for daily use. Any stable material can be used for daily monitoring of drift.
NOTE 4—The effect of drift correction on the precision and bias of this test method has not been studied.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference Materials, American Chemical Society, Washington, DC. For
suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and
the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
D4929 − 22
25.5.1 Drift correction is usually implemented automatically in software, although the calculation can readily be done manually.
For X-ray instruments that are highly stable, t
...