ASTM D1266-18

Standard Test Method for Sulfur in Petroleum Products (Lamp Method)

SIGNIFICANCE AND USE
4.1 This test method provides a means of monitoring the sulfur level of various petroleum products and additives. This knowledge can be used to predict performance, handling, or processing properties. In some cases the presence of sulfur components is beneficial to the product and monitoring the depletion of sulfur compounds provides useful information. In other cases the presence of sulfur compounds is detrimental to the processing or use of the product.
SCOPE
1.1 This test method covers the determination of total sulfur in liquid petroleum products in concentrations from 0.01 % to 0.4 % by mass (Note 1). A special sulfate analysis procedure is described in Annex A1 that permits the determination of sulfur in concentrations as low as 5 mg/kg.  
Note 1: The comparable lamp method for the determination of sulfur in liquefied petroleum gas is described in Test Method D2784. For the determination of sulfur in heavier petroleum products that cannot be burned in a lamp, see the high pressure decomposition device method (Test Method D129) the quartz tube method (IP 63), or the high-temperature method (Test Method D1552).  
1.2 The direct burning procedure (Section 9) is applicable to the analysis of such materials as gasoline, kerosine, naphtha, and other liquids that can be burned completely in a wick lamp. The blending procedure (Section 10) is applicable to the analysis of gas oils and distillate fuel oils, naphthenic acids, alkyl phenols, high sulfur content petroleum products, and many other materials that cannot be burned satisfactorily by the direct burning procedure.  
1.3 Phosphorus compounds normally present in commercial gasoline do not interfere. A correction is given for the small amount of acid resulting from the combustion of the lead anti-knock fluids in gasolines. Appreciable concentrations of acid-forming or base-forming elements from other sources interfere when the titration procedure is employed since no correction is provided in these cases.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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: 31-Mar-2018
• ICS: 75.080 - Petroleum products in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.03 - Elemental Analysis

Relations

• Replaces: ASTM D1266-13 - Standard Test Method for Sulfur in Petroleum Products (Lamp Method)
• Effective Date: 01-Apr-2018
• 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 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 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 D6792-23c - Standard Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
• Effective Date: 01-Nov-2023
• Refers: ASTM D6792-23b - Standard Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
• Effective Date: 01-Oct-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 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 D6299-17 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Jan-2017
• Refers: ASTM D1552-16 - Standard Test Method for Sulfur in Petroleum Products by High Temperature Combustion and Infrared (IR) Detection or Thermal Conducitivity Detection (TCD)
• Effective Date: 01-Jul-2016
• Refers: ASTM D6300-16 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Apr-2016
• Refers: ASTM D6300-15 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2015
• Refers: ASTM D1552-08(2014) - Standard Test Method for Sulfur in Petroleum Products (High-Temperature Method)
• Effective Date: 15-Jun-2014
• Refers: ASTM D6300-14ae1 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014

Overview

ASTM D1266-18: Standard Test Method for Sulfur in Petroleum Products (Lamp Method) is an internationally recognized procedure developed by ASTM International. This standard outlines a laboratory test method for determining total sulfur content in liquid petroleum products, including gasoline, kerosine, naphtha, gas oils, distillate fuel oils, naphthenic acids, alkyl phenols, and other similar materials. The method is suitable for sulfur concentrations ranging from 0.01% to 0.4% by mass, with an additional procedure for detecting trace levels of sulfur down to 5 mg/kg. Accurate monitoring of sulfur in fuels and lubricants is critical to meet performance, safety, and environmental requirements.

Key Topics

• Test Methodology: The procedure involves burning the petroleum sample in a closed system lamp with a controlled atmosphere. The sulfur present is converted to sulfur dioxide during combustion, ultimately absorbed and measured by standardized titration or gravimetric techniques.
• Applicability: The lamp method is applicable to a wide range of liquid petroleum products that can be completely combusted using a wick lamp. Alternative blending procedures are included for materials that cannot be directly burned.
• Trace Sulfur Detection: Annex A1 provides a specialized approach for the analysis of sulfur at concentrations as low as 5 mg/kg using a turbidimetric method.
• Interference and Quality Control: The method includes procedures to correct for acid-forming or base-forming elements and addresses potential interferences, especially from lead anti-knock compounds in gasoline.
• Reproducibility and Repeatability: Guidance on precision and statistical quality control is provided, promoting reliable results across different laboratories and analysts.

Applications

ASTM D1266-18 is a key reference for:

• Refineries and Laboratories: Ensuring sulfur content in fuels and additives complies with regulatory and performance specifications.
• Product Development: Monitoring the sulfur level enables formulation adjustments to optimize fuel performance and ensure compliance with sulfur limits.
• Regulatory Compliance: Meeting emissions standards and fuel quality regulations, where excess sulfur might lead to environmental or engine issues.
• Quality Assurance: Ongoing production and batch testing for sulfur, supporting ISO or API quality management systems.
• Research and Development: Characterization of new petroleum blends, additives, and specialty chemicals with regards to sulfur content.

Related Standards

The ASTM D1266-18 standard is widely referenced alongside the following standards for sulfur analysis in petroleum products:

• ASTM D129 - Determination of sulfur in heavier petroleum products using a high pressure decomposition device.
• ASTM D1552 - High-temperature combustion methods for sulfur detection (IR/TCD).
• ASTM D2784 - Lamp method for liquefied petroleum gas (withdrawn 2016).
• Energy Institute IP 63 - Sulfur content determination by the quartz tube method.
• ISO and ASTM Quality Standards: D4057, D4177 for sampling, D6299 and D6792 for quality management, and D1193 for reagent water guidelines.

Practical Value

Implementing ASTM D1266-18 helps organizations:

• Monitor and control sulfur levels to optimize product performance and adherence to regulations.
• Minimize risks of equipment corrosion and emissions problems due to excess or insufficient sulfur.
• Achieve consistent quality documentation and product certification for petroleum-based products in global markets.
• Support internal and external audits with standardized, reproducible test results.

For up-to-date methods and regulatory acceptance, always refer to the current official ASTM standard and relevant internationally recognized quality management protocols.

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: D1266 − 18
Designation: 107/86
Standard Test Method for
Sulfur in Petroleum Products (Lamp Method)
This standard is issued under the fixed designation D1266; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This test method covers the determination of total sulfur
1.6 This international standard was developed in accor-
in liquid petroleum products in concentrations from 0.01 % to
dance with internationally recognized principles on standard-
0.4 % by mass (Note 1).Aspecial sulfate analysis procedure is
ization established in the Decision on Principles for the
described in AnnexA1 that permits the determination of sulfur
Development of International Standards, Guides and Recom-
in concentrations as low as 5 mg⁄kg.
mendations issued by the World Trade Organization Technical
NOTE 1—The comparable lamp method for the determination of sulfur
Barriers to Trade (TBT) Committee.
in liquefied petroleum gas is described in Test Method D2784. For the
determination of sulfur in heavier petroleum products that cannot be
2. Referenced Documents
burned in a lamp, see the high pressure decomposition device method
2.1 ASTM Standards:
(Test Method D129) the quartz tube method (IP 63), or the high-
temperature method (Test Method D1552).
D129 Test Method for Sulfur in Petroleum Products (Gen-
eral High Pressure Decomposition Device Method)
1.2 Thedirectburningprocedure(Section9)isapplicableto
D1193 Specification for Reagent Water
the analysis of such materials as gasoline, kerosine, naphtha,
D1552 Test Method for Sulfur in Petroleum Products by
andotherliquidsthatcanbeburnedcompletelyinawicklamp.
High Temperature Combustion and Infrared (IR) Detec-
The blending procedure (Section 10) is applicable to the
tion or Thermal Conductivity Detection (TCD)
analysis of gas oils and distillate fuel oils, naphthenic acids,
D2784 Standard Test Method for Sulfur in Liquefied Petro-
alkyl phenols, high sulfur content petroleum products, and
leum Gases (Oxy-Hydrogen Burner or Lamp) (Withdrawn
manyothermaterialsthatcannotbeburnedsatisfactorilybythe
2016)
direct burning procedure.
D4057 Practice for Manual Sampling of Petroleum and
1.3 Phosphorus compounds normally present in commercial
Petroleum Products
gasoline do not interfere. A correction is given for the small
D4177 Practice for Automatic Sampling of Petroleum and
amount of acid resulting from the combustion of the lead
Petroleum Products
anti-knock fluids in gasolines. Appreciable concentrations of
D6299 Practice for Applying Statistical Quality Assurance
acid-forming or base-forming elements from other sources
and Control Charting Techniques to Evaluate Analytical
interfere when the titration procedure is employed since no
Measurement System Performance
correction is provided in these cases.
D6300 Practice for Determination of Precision and Bias
1.4 The values stated in SI units are to be regarded as
Data for Use in Test Methods for Petroleum Products and
standard. No other units of measurement are included in this
Lubricants
standard.
D6792 Practice for Quality Management Systems in Petro-
leum Products, Liquid Fuels, and Lubricants Testing
1.5 This standard does not purport to address all of the
Laboratories
safety concerns, if any, associated with its use. It is the
E11 Specification for Woven Wire Test Sieve Cloth and Test
responsibility of the user of this standard to establish appro-
Sieves
1 2
This test method is under the jurisdiction of ASTM Committee D02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Subcommittee D02.03 on Elemental Analysis. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2018. Published April 2018. Originally the ASTM website.
approved in 1969. Last previous edition approved in 2013 as D1266 – 13. DOI: The last approved version of this historical standard is referenced on
10.1520/D1266-18. www.astm.org.
*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
D1266 − 18
5. Apparatus
5.1 Absorbers, Chimneys, Lamps, and Spray Traps (Fig. 1),
as required are described in detail in Annex A3. The standard
flask and burner (Fig. A3.1) as shown is not suitable for
burning highly aromatic mixtures without blending. The flask
and burner for aromatic samples (Fig. A3.1) permits burning
these samples directly without blending and may also be used
to burn nonaromatic samples; with this lamp, a second port
with control valve in the burner manifold is required.
5,6
5.2 Cotton Wicking —Clean, unused, uniform, twisted
white cotton yarn of good quality. For the burner to burn
aromatic samples use long staple, fine-spun, commercial fine
6,7
grade.
5.3 Manifold System, consisting of a vacuum manifold with
regulating device, valves, and so forth (Fig. 2) and a dual
manifold (burner and chimney) supplying a gas mixture of
approximately 70 % carbon dioxide (CO ) and 30 % oxygen
(O ) at regulated pressures. The vacuum manifold shall be
FIG. 1 Illustrative Sketch of the Assembled Lamp Unit
connected to a pump of sufficient capacity to permit a steady
gas flow of about 3 L⁄min through each absorber and to
maintain a constant manifold pressure of approximately 40 cm
2.2 Energy Institute Standard:
of water below atmospheric. The gas mixture in the chimney
IP 63 Sulfur Content—The Quartz Tube Method
manifold shall be maintained at a nearly constant pressure of
3. Summary of Test Method 1 cm to 2 cm of water and the burner manifold at approxi-
mately 20 cm of water.Asuitable arrangement is shown in Fig.
3.1 The sample is burned in a closed system, using a
2 and described in AnnexA3, but any other similar system can
suitablelamp(Fig.1)andanartificialatmospherecomposedof
be used. Modifications of the manifold and associated equip-
70 % carbon dioxide and 30 % oxygen to prevent formation of
ment for burning samples in air are shown in Fig. A2.1 and
nitrogen oxides. The oxides of sulfur are absorbed and oxi-
described in Annex A2.
dized to sulfuric acid by means of hydrogen peroxide solution
which is then flushed with air to remove dissolved carbon
6. Reagents and Materials
dioxide. Sulfur as sulfate in the absorbent is determined
acidimetrically by titration with standard sodium hydroxide
6.1 Purity of Reagents—Reagent grade chemicals shall be
solution, or gravimetrically by precipitation as barium sulfate
used in all tests. Unless otherwise indicated, it is intended that
(see Annex A2).
all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society,
3.2 Alternatively, the sample may be burned in air, the
where such specifications are available. Other grades may be
sulfur as sulfate in the absorbent being determined by precipi-
used, provided it is first ascertained that the reagent is of
tation as barium sulfate for weighing (see Annex A2).
sufficiently high purity to permit its use without lessening the
NOTE 2—In the absence of acid-forming or base-forming elements,
accuracy of the determination.
other than sulfur, results by the volumetric and gravimetric finishes
described are equivalent within the limits of precision of the method.
6.2 Purity of Water—Unless otherwise indicated, references
3.3 For sulfur contents below 0.01 % by mass, it is neces- to water shall be understood to mean reagent water as defined
by Type II or Type III of Specification D1193.
sary to determine the sulfate content in the absorber solution
turbidimetrically as barium sulfate (see Annex A1).
4. Significance and Use
The sole source of supply of cotton wicking, yarn, white, 4-strand (2 mg ⁄cm-
4.1 This test method provides a means of monitoring the ⁄strand to 3 mg ⁄cm ⁄strand) known to the committee at this time is Koehler
Instrument Co., 1595 SycamoreAve., Bohemia, NY11716, or the type marketed by
sulfur level of various petroleum products and additives. This
various suppliers in the United Kingdom as 13s/14 ends, scoured, and bleached.
knowledge can be used to predict performance, handling, or
If you are aware of alternative suppliers, please provide this information to
processing properties. In some cases the presence of sulfur
ASTM International Headquarters. Your comments will receive careful consider-
ation at a meeting of the responsible technical committee, which you may attend.
components is beneficial to the product and monitoring the
The sole source of supply of fine grade known to the committee at this time is
depletion of sulfur compounds provides useful information. In
Thomas Scientific, P.O. Box 99, Swedesboro, NJ 08085-0099.
other cases the presence of sulfur compounds is detrimental to 8
Reagent Chemicals, American Chemical Society Specifications, American
the processing or use of the product.
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
listed by the American Chemical Society, see Annual Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Available from Energy Institute, 61 New Cavendish St., London, W1G 7AR, and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
U.K., http://www.energyinst.org. MD.
D1266 − 18
FIG. 2 Schematic Diagram of CO -O Supply Manifold and Lamp System
2 2
6.3 Carbon Dioxide and Oxygen—The carbon dioxide 6.10 Quality Control (QC) Sample(s), preferably are por-
(CO ) and the oxygen (O ) shall each be at least 99.5 % pure. tions of one or more liquid petroleum materials or product
2 2
These gases shall meet the requirements of 9.5. standards of known sulfur content that were not used in the
generation of the instrument calibration curve. These (QC)
6.4 Diluent—The diluent used shall have a sulfur content
samples are to be used to check the validity of the testing
less than 0.001 mass %, be completely miscible with the
process as described in Section 12. An ample supply of QC
sample to be analyzed, and permit burning at a moderate rate
sample material shall be available for the intended period of
without smoking. Normal heptane, isooctane, and absolute
use,andmustbehomogeneousandstableundertheanticipated
ethyl alcohol have been found suitable (Note 9).
storage conditions.
6.5 Hydrochloric Acid (1 + 10)—Mix 1 volume of concen-
7. Preparation of Apparatus
trated hydrochloric acid (HCl, relative density 1.19) with 10
volumes of water.
7.1 Take samples in accordance with the instructions in
Practices D4057 or D4177.
6.6 Hydrogen Peroxide Solution (1 + 19) —Mix 1 volume
of concentrated hydrogen peroxide (H O , 30 %) with 19
7.2 When the apparatus is first assembled, charge the
2 2
volumes of water. Store in a dark-colored glass-stoppered
absorber with 30 mL 6 2 mL of water. Adjust the individual
bottle.
valves between the vacuum manifold and spray traps so that
approximately3 Lofairperminutewillbedrawnthrougheach
6.7 Methyl Purple Indicator—Aqueous solution containing
absorber when the chimney outlets are open to the atmosphere,
approximately 0.1 % active constituent. (Not methyl violet.)
while maintaining the pressure in the vacuum manifold at
6.8 Sodium Hydroxide Solution (100 g/L)—Dissolve 100 g
approximately 40 cm of water below atmospheric. When all
of sodium hydroxide (NaOH) in water and dilute to 1 L.
adjustments have been made, remove the water from the
6.9 Sodium Hydroxide, Standard Solution (0.05 M)—Dilute
absorbers.Theheightoftheliquidsinthepressureandvacuum
2.8 mL of saturated NaOH solution to 1 L (Note 3), using for regulators is indicated in Fig. 2, and during operation a slow
thispurposetheclearsaturatedsolutiondecantedafterstanding
leak of gas should be maintained through them.
long enough to permit any precipitate to settle out. Standardize
NOTE 4—In use, place 300 mL to 400 mL of H O solution (1 + 19) in
2 2
by titration against standard acid, using the methyl purple
the scrubber. Since the manifold manometer also serves as a scrubber at
indicator. Store in an alkali-resistant glass bottle and protect to
the end of the test to remove CO from the absorbent use H O solution
2 2 2
(1 + 19) as the manometric liquid. Replace weekly or whenever the
minimize contamination by CO from the air. Use only pure
volume becomes appreciably less than the original.
gum rubber tubing for connections between the storage bottles
7.3 Neutralize the H O solution (1 + 19) immediately be-
and burets.
2 2
fore use. As 30 mL of the solution is needed, transfer to a
NOTE 3—The calculation of results can be simplified by adjusting the
beaker multiples of 30 mLsufficient for the number of absorb-
molarity of the NaOH solution to 0.0624 6 0.0001. Then 1 mL of the
ers to be used simultaneously. Add 1 drop of methyl purple
NaOH solution will be equivalent to 0.0010 g of sulfur. In this case, the
factor 16.03M in the calculation (see 12.1) becomes 1.000. indicator solution for each 100 mL of H O solution and then
2 2
add 0.05 N NaOH solution dropwise until the color changes
from purple to light green.
Fleisher Methyl Purple Indicator, U. S. Patent No. 2416619 may be obtained
7.4 Introduce 30 mL 6 2 mL of the freshly neutralized
from Harry Fleisher Chemical Co., Benjamin Franklin Station, Washington, DC
20044, or from any chemical supply company handling Fleisher Methyl Purple. H O solution (1 + 19) into the larger bulb of each absorber. In
2 2
D1266 − 18
TABLE 1 Sample Size for Direct Combustion of Liquid Samples
addition, for each set of samples burned, prepare an extra
absorber for use as a control blank. Attach the spray traps and Sulfur Content, Sample Size
mass percent gmL
chimneys and connect them to their respective manifolds by
Under 0.05 10 to 15 20
means of sulfur-free rubber tubing. Close the chimney open-
0.05 to 0.4 5 to 10 10
ings by means of corks.
7.5 With the burner control valves closed, the valve to the
vacuum regulator fully open, and the pressure in the vacuum
introduce a small amount of combustion atmosphere into the
manifold adjusted to approximately 40 cm of water below
flask to provide sufficient vapor for lighting the burner. After
atmospheric, turn on the CO and O supplies. (Warning—A
2 2
lighting the burner, introduce combustion atmosphere directly
hazardous (explosive) condition can result if the CO supply is
2 into the burner to prevent smoking and to adjust the flame size.
interrupted and the O flow is continued while samples are
If the flame is accidentally snuffed out, relight.
being burned. The installation of suitable warning or control
8.5 A short burning period (1 min to 2 min is usually
equipment is recommended.) Adjust the chimney manifold
sufficient)atlowflameheightisnecessarytoallowcombustion
control valve so that, at the required rate of flow through the
to reach equilibrium before the flame size can be increased
absorbers, only a small stream of CO –O gas escapes at the
2 2
without causing a smoky flame. In adjusting the standard lamp,
pressure regulator, a small stream of air enters at the vacuum
the entire control is at the burner. For the burner for aromatic
regulator, and the pressure in the chimney manifold is 1 cm to
samples, first adjust the flow of gas to the flask and then reduce
2 cm of water. Minor adjustment of the vacuum regulator and
the flow of gas to the burner as required. In any case, it is
vacuum control valve may be necessary to achieve this
essential that the flame burn smoothly and symmetrically and
condition (Note 5).
without jets in the inner cone or smoke on the outer fringes.
NOTE 5—It is convenient to balance the gas flow system by regulating
8.6 Satisfactory combustion of materials difficult to burn
the pressure in the vacuum manifold. This is done by raising or lowering
can sometimes be obtained by increasing the O content of the
the air inlet tube in the vacuum regulator by sliding it in a rubber sleeve. 2
combustion atmosphere. Never increase the O content of the
7.6 Cut the wicking to 30 cm lengths. Use the number of
combustion atmosphere to more than 40 %.
lengthsdictatedbythesample(seeSection8);foldthewicking
8.7 Before extinguishing the flames, allow the sample to
once to give a 15 cm long bundle for threading the burners.
burn until the flask and wicking appear to be dry and the flame
Thread the required number of burners by inserting the looped
has reduced considerably in size; frequently the flame contin-
ends into the top of the inner tube of the burner. Draw the
ues to burn a short time after the flask appears dry because of
wicking through by means of a metal hook. Trim the wick as
the sample in the wick. For example, for gasoline samples,
close as possible to the top of the burner with a pair of sharp
whichburnwithahighflame,theflameshouldbeextinguished
scissors.Itisessentialthatthoroughlycleanedburnersandnew
when it is only 3 mm to 4 mm high. If the flame is permitted to
wicking be used for each test.
burn until it goes out, partially oxidized substances (probably
8. Control of Combustion
organic acids) are produced; as a result broad, indistinct end
points are obtained. When samples are not burned until the
8.1 Most types of liquid samples burn with a luminous
flask is apparently dry, erratic results may be obtained. In the
yellow flame, the size and shape of which is dependent on the
case of volatile samples, any unburned sample will escape
gas flow to the burner, the volatility of the material, the
from the burner during weighing. When elemental sulfur is
tightness of the fit of the wick in the burner tube, and the
present,itisparticularlyimportantthatthesamplebeburnedto
position of the top of the wick relative to the top of the burner.
apparentdrynessandthatthewickbemaintainedflushwiththe
It is preferable that the latter two variables be fixed with
top of the burner to ensure complete combustion. With mix-
relation to the first before burning is started so that the flame
tures containing light and heavy hydrocarbons, the more
can be controlled by variation in the rate of CO –O flow.
2 2
volatile materials seem to burn first, possibly concentrating
8.2 Highly volatile samples require a tight-fitting wick, the
sulfur compounds in the material remaining behind.
top of which can need to be several millimetres below the top
of the burner, and in extreme cases may have to be cooled in
9. Procedure for Direct Combustion of Liquid Samples
ice during the burning. Less volatile materials require a more
(see also Annex A2)
loosely fitting wick and can require warming.
9.1 By means of an appropriate pipet, introduce into the
8.3 After trimming, draw the wick down until the trimmed
flask of each lamp an approximate quantity of sample as
edge is flush with or just a little below the top of the burner.
indicated in Table 1. Stopper the flasks with clean, numbered
Withtheburnerforaromaticsamples,thedistancefromthetop
corks. Weigh each flask and its burner to the nearest 0.005 g.
of the burner to the top of the wicking should be 8 mm or more
NOTE 6—While the stoppered flasks and prepared burners can all be
for benzene and 4 mm for toluene; a slight heating of the upper
weighed separately, it is usually more convenient to place each flask and
end of the burner will be helpful in starting vaporization of
its burner on the balance pan and obtain the combined weight in a single
heavier materials.
weighing.
8.4 To use the standard lamp, light the wick and then slowly 9.2 Handlingeachlampindividually,inserttheburnerinthe
admit combustion atmosphere to the burner to obtain a flask.As soon as the sample has risen by capillary action to the
smoke-free flame. To use the burner for aromatic samples, top of the wick, connect the side tube of the burner to the
D1266 − 18
TABLE 2 Sample Size for Testing Blended Liquid Samples
burner manifold by means of sulfur-free rubber tubing. Light
the burner with a sulfur-free flame (such as an alcohol lamp) Sulfur Content, Sample Size
mass percent gmL
and insert into the chimney, pinching off the connection
0.4 and under 3 to 4 5
between the chimney and the chimney manifold during the
insertion if the flame tends to be blown out. At the same time,
adjust the gas flow to the burner so that the flame is maintained
at a point just below smoking and has a steady symmetrical
appearance. Continue in this manner until all lamps have been
0.005 g. By means of a pipet, introduce into the flask of each
placed in the chimneys. Make any minor adjustment of the
burner an approximate quantity of sample as indicated in Table
chimney manifold control valve necessary to maintain the
2; swirl to mix thoroughly, and reweigh.
required pressure (see Section 7). During the burning, and
NOTE9—Alternatively,makeaquantitative40 %blendofthesamplein
particularly during the latter stages when the flame becomes
sulfur-free diluent and proceed as described in Section 9.
small, decrease the CO –O supply to the burners in order to
2 2
prevent extinction of the flames.
10.2 Insert the burner and burn as described in 9.2. Remove
each lamp from its chimney as the flame nears extinction and
NOTE 7—When incomplete combustion occurs, the absorber liquid will
extinguish the flame.Add 2 mLof diluent, allowing the diluent
foam excessively.
to rinse down the walls of the flask. Burn the additional diluent
9.3 When the burning of each sample is complete, as
andrepeattheadditionofdiluentandburningonemoretimeso
evidenced by the flame becoming small owing to depletion of
that a total of 10 mL of diluent has been burned.
the sample, remove the burner and flask from the chimney,
extinguish the flame, shut off the CO –O supply to the burner NOTE 10—In this case, it is desirable that a 10 mLdiluent blank be run;
2 2
the titration of the absorber solution from this blank, shall not exceed
and stopper the chimney opening. Immediately reweigh the
0.1 mL of 0.05 M NaOH solution.
flask, burner, and numbered cork. When all combustions have
10.3 After all lamps have completed burning, turn off the
been completed, turn off the CO and the O supplies, close the
2 2
CO and O supplies, close the connection to the vacuum
chimney control valve, and close the connection to the vacuum
2 2
regulator, draw air through the absorbers for 5 min, and finally
regulator; this will cause air to be drawn into the chimney
close the vacuum control valve. Rinse the chimneys and spray
manifold through the manometer. Allow air to be drawn
traps three times, using about 10 mL of water each time. Add
through the absorbers in this manner for 5 min to remove
the rinsings to the absorbers, and titrate as directed in Section
dissolved CO from the absorbent; then close the vacuum
11.
control valve.
NOTE8—Ifitisdesiredtoconservethecombustionatmosphere,thegas
11. Titration of Absorbent Solution
flow through each individual absorber can be turned off upon completion
of the burning period. To accomplish this, pinch off the rubber tubing
11.1 Add 3 to 4 drops of methyl purple indicator solution to
connecting the spray trap to the vacuum manifold, reduce the flow of
the liquid in each absorber. Titrate the absorbent solution by
mixed gases at the rotameters proportionately, and readjust the vacuum
introducing 0.05 N NaOH solution from a buret into the
control valve and the chimney control valve. When the burning of all
smaller bulb of the absorber. Use a 10-mL microburet if less
samples has been completed, it is necessary to remove the pinch clamps
and readjust the vacuum control valve in order to draw air at the required
than 10 mg of sulfur is expected to be present in the absorber.
rate through the absorbers for removal of dissolved CO .
Stir during the titration by applying suction intermittently to
9.4 Rinse the chimneys and spray traps three times, using the top of the larger bulb.
about 10 mL of water each time. When the sample contains
NOTE 11—When incomplete combustion of the sample occurs, the air
leadanti-knockfluids,usehotwatertorinsethechimneys.Add
drawn through the absorber during the titration will have a characteristic
the rinsing to the absorbers, and titrate as directed in Section
taste or odor and the end point will be broad. In these cases, discard the
determination.
11.
9.5 Blank—Leave the chimney of the blank absorber (see
12. Calculations
7.4)
...

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: D1266 − 13 D1266 − 18
Designation: 107/86
Standard Test Method for
Sulfur in Petroleum Products (Lamp Method)
This standard is issued under the fixed designation D1266; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This test method covers the determination of total sulfur in liquid petroleum products in concentrations from 0.01 to 0.4
mass % (0.01 % to 0.4 % by mass (Note 1). A special sulfate analysis procedure is described in Annex A1 that permits the
determination of sulfur in concentrations as low as 55 mg mg/kg. ⁄kg.
NOTE 1—The comparable lamp method for the determination of sulfur in liquefied petroleum gas is described in Test Method D2784. For the
determination of sulfur in heavier petroleum products that cannot be burned in a lamp, see the high pressure decomposition device method (Test Method
D129) the quartz tube method (IP 63), or the high-temperature method (Test Method D1552).
1.2 The direct burning procedure (Section 9) is applicable to the analysis of such materials as gasoline, kerosine, naphtha, and
other liquids that can be burned completely in a wick lamp. The blending procedure (Section 10) is applicable to the analysis of
gas oils and distillate fuel oils, naphthenic acids, alkyl phenols, high sulfur content petroleum products, and many other materials
that cannot be burned satisfactorily by the direct burning procedure.
1.3 Phosphorus compounds normally present in commercial gasoline do not interfere. A correction is given for the small amount
of acid resulting from the combustion of the lead anti-knock fluids in gasolines. Appreciable concentrations of acid-forming or
base-forming elements from other sources interfere when the titration procedure is employed since no correction is provided in
these cases.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 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.
2. Referenced Documents
2.1 ASTM Standards:
D129 Test Method for Sulfur in Petroleum Products (General High Pressure Decomposition Device Method)
D1193 Specification for Reagent Water
D1552 Test Method for Sulfur in Petroleum Products by High Temperature Combustion and Infrared (IR) Detection or Thermal
Conductivity Detection (TCD)
D2784 Standard Test Method for Sulfur in Liquefied Petroleum Gases (Oxy-Hydrogen Burner or Lamp) (Withdrawn 2016)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
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 June 15, 2013April 1, 2018. Published August 2013April 2018. Originally approved in 1969. Last previous edition approved in 20072013 as
D1266 – 07.D1266 – 13. DOI: 10.1520/D1266-13.10.1520/D1266-18.
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.
The last approved version of this historical standard is referenced on www.astm.org.
*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
D1266 − 18
FIG. 1 Illustrative Sketch of the Assembled Lamp Unit
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 and Lubricants
D6792 Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
2.2 Energy Institute Standard:
IP 63 Sulfur Content—The Quartz Tube Method
3. Summary of Test Method
3.1 The sample is burned in a closed system, using a suitable lamp (Fig. 1) and an artificial atmosphere composed of 70 %
carbon dioxide and 30 % oxygen to prevent formation of nitrogen oxides. The oxides of sulfur are absorbed and oxidized to sulfuric
acid by means of hydrogen peroxide solution which is then flushed with air to remove dissolved carbon dioxide. Sulfur as sulfate
in the absorbent is determined acidimetrically by titration with standard sodium hydroxide solution, or gravimetrically by
precipitation as barium sulfate (see Annex A2).
3.2 Alternatively, the sample may be burned in air, the sulfur as sulfate in the absorbent being determined by precipitation as
barium sulfate for weighing (see Annex A2).
NOTE 2—In the absence of acid-forming or base-forming elements, other than sulfur, results by the volumetric and gravimetric finishes described are
equivalent within the limits of precision of the method.
3.3 For sulfur contents below 0.01 mass % 0.01 % by mass, it is necessary to determine the sulfate content in the absorber
solution turbidimetrically as barium sulfate (see Annex A1).
4. Significance and Use
4.1 This test method provides a means of monitoring the sulfur level of various petroleum products and additives. This
knowledge can be used to predict performance, handling, or processing properties. In some cases the presence of sulfur
components is beneficial to the product and monitoring the depletion of sulfur compounds provides useful information. In other
cases the presence of sulfur compounds is detrimental to the processing or use of the product.
5. Apparatus
5.1 Absorbers, Chimneys, Lamps, and Spray Traps (Fig. 1), as required are described in detail in Annex A3. The standard flask
and burner (Fig. A3.1) as shown is not suitable for burning highly aromatic mixtures without blending. The flask and burner for
aromatic samples (Fig. A3.1) permits burning these samples directly without blending and may also be used to burn nonaromatic
samples; with this lamp, a second port with control valve in the burner manifold is required.
Available from Energy Institute, 61 New Cavendish St., London, WIGW1G 7AR, U.K., http://www.energyinst.org.uk.http://www.energyinst.org.
D1266 − 18
FIG. 2 Schematic Diagram of CO -O Supply Manifold and Lamp System
2 2
5,6
5.2 Cotton Wicking —Clean, unused, uniform, twisted white cotton yarn of good quality. For the burner to burn aromatic
6,7
samples use long staple, fine-spun, commercial fine grade.
5.3 Manifold System, consisting of a vacuum manifold with regulating device, valves, and so forth (Fig. 2) and a dual manifold
(burner and chimney) supplying a gas mixture of approximately 70 % carbon dioxide (CO ) and 30 % oxygen (O ) at regulated
2 2
pressures. The vacuum manifold shall be connected to a pump of sufficient capacity to permit a steady gas flow of about 33 L
L/min ⁄min through each absorber and to maintain a constant manifold pressure of approximately 40 cm 40 cm of water below
atmospheric. The gas mixture in the chimney manifold shall be maintained at a nearly constant pressure of 11 cm to 2 cm 2 cm
of water and the burner manifold at approximately 20 cm 20 cm of water. A suitable arrangement is shown in Fig. 2 and described
in Annex A3, but any other similar system can be used. Modifications of the manifold and associated equipment for burning
samples in air are shown in Fig. A2.1 and described in Annex A2.
6. Reagents and Materials
6.1 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.
6.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water as defined by
Type II or Type III of Specification D1193.
6.3 Carbon Dioxide and Oxygen—The carbon dioxide (CO ) and the oxygen (O ) shall each be at least 99.5 % pure. These
2 2
gases shall meet the requirements of 9.5.
6.4 Diluent—The diluent used shall have a sulfur content less than 0.001 mass %, be completely miscible with the sample to
be analyzed, and permit burning at a moderate rate without smoking. Normal heptane, isooctane, and absolute ethyl alcohol have
been found suitable (Note 9).
6.5 Hydrochloric Acid (1 + 10)—Mix 1 volume of concentrated hydrochloric acid (HCl, relative density 1.19) with 10 volumes
of water.
6.6 Hydrogen Peroxide Solution (1 + 19) —Mix 1 volume of concentrated hydrogen peroxide (H O , 30 %) 30 %) with 19
2 2
volumes of water. Store in a dark-colored glass-stoppered bottle.
The sole source of supply of cotton wicking, yarn, white, 4–strand (24-strand (2 mg ⁄cm ⁄strand to 33 mg ⁄cm mg/cm/strand) ⁄strand) known to the committee at this time
is Koehler Instrument Co., 1595 Sycamore Ave., Bohemia, NY 11716, or the type marketed by various suppliers in the United Kingdom as 13s/14 ends, scoured, and bleached.
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.
The sole source of supply of fine grade known to the committee at this time is Thomas Scientific, P.O. Box 99, Swedesboro, NJ 08085-0099.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed by
the American Chemical Society, see Annual 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.
D1266 − 18
6.7 Methyl Purple Indicator—Aqueous solution containing approximately 0.1 % active constituent. (Not methyl violet.)
6.8 Sodium Hydroxide Solution (100 g/L)—Dissolve 100 g 100 g of sodium hydroxide (NaOH) in water and dilute to 1 L.1 L.
6.9 Sodium Hydroxide, Standard Solution (0.05 M)—Dilute 2.8 mL 2.8 mL of saturated NaOH solution to 1 L 1 L (Note 3),
using for this purpose the clear saturated solution decanted after standing long enough to permit any precipitate to settle out.
Standardize by titration against standard acid, using the methyl purple indicator. Store in an alkali-resistant glass bottle and protect
to minimize contamination by CO from the air. Use only pure gum rubber tubing for connections between the storage bottles and
burets.
NOTE 3—The calculation of results can be simplified by adjusting the molarity of the NaOH solution to 0.0624 6 0.0001. Then 1 mL 1 mL of the NaOH
solution will be equivalent to 0.0010 g 0.0010 g of sulfur. In this case, the factor 16.03M in the calculation (see 12.1) becomes 1.000.
6.10 Quality Control (QC) Sample(s), preferably are portions of one or more liquid petroleum materials or product standards
of known sulfur content that were not used in the generation of the instrument calibration curve. These (QC) samples are to be
used to check the validity of the testing process as described in Section 12. An ample supply of QC sample material shall be
available for the intended period of use, and must be homogeneous and stable under the anticipated storage conditions.
7. Preparation of Apparatus
7.1 Take samples in accordance with the instructions in Practices D4057 or D4177.
7.2 When the apparatus is first assembled, charge the absorber with 3030 mL 6 2 mL 2 mL of water. Adjust the individual
valves between the vacuum manifold and spray traps so that approximately 3 L 3 L of air per minute will be drawn through each
absorber when the chimney outlets are open to the atmosphere, while maintaining the pressure in the vacuum manifold at
approximately 40 cm 40 cm of water below atmospheric. When all adjustments have been made, remove the water from the
absorbers. The height of the liquids in the pressure and vacuum regulators is indicated in Fig. 2, and during operation a slow leak
of gas should be maintained through them.
NOTE 4—In use, place 300300 mL to 400 mL 400 mL of H O solution (1 + 19) in the scrubber. Since the manifold manometer also serves as a scrubber
2 2
at the end of the test to remove CO from the absorbent use H O solution (1 + 19) as the manometric liquid. Replace weekly or whenever the volume
2 2 2
becomes appreciably less than the original.
7.3 Neutralize the H O solution (1 + 19) immediately before use. As 30 mL 30 mL of the solution is needed, transfer to a
2 2
beaker multiples of 30 mL 30 mL sufficient for the number of absorbers to be used simultaneously. Add 1 drop of methyl purple
indicator solution for each 100 mL 100 mL of H O solution and then add 0.05 0.05 N NaOH solution dropwise until the color
2 2
changes from purple to light green.
7.4 Introduce 3030 mL 6 2 mL 2 mL of the freshly neutralized H O solution (1 + 19) into the larger bulb of each absorber.
2 2
In addition, for each set of samples burned, prepare an extra absorber for use as a control blank. Attach the spray traps and
chimneys and connect them to their respective manifolds by means of sulfur-free rubber tubing. Close the chimney openings by
means of corks.
7.5 With the burner control valves closed, the valve to the vacuum regulator fully open, and the pressure in the vacuum manifold
adjusted to approximately 40 cm 40 cm of water below atmospheric, turn on the CO and O supplies. (Warning—WarningA—A
2 2
hazardous (explosive) condition can result if the CO supply is interrupted and the O flow is continued while samples are being
2 2
burned. The installation of suitable warning or control equipment is recommended.) Adjust the chimney manifold control valve
so that, at the required rate of flow through the absorbers, only a small stream of CO -O–O gas escapes at the pressure regulator,
2 2
a small stream of air enters at the vacuum regulator, and the pressure in the chimney manifold is 11 cm to 2 cm 2 cm of water.
Minor adjustment of the vacuum regulator and vacuum control valve may be necessary to achieve this condition (Note 5).
NOTE 5—It is convenient to balance the gas flow system by regulating the pressure in the vacuum manifold. This is done by raising or lowering the
air inlet tube in the vacuum regulator by sliding it in a rubber sleeve.
7.6 Cut the wicking to 30-cm30 cm lengths. Use the number of lengths dictated by the sample (see Section 8); fold the wicking
once to give a 15-cm15 cm long bundle for threading the burners. Thread the required number of burners by inserting the looped
ends into the top of the inner tube of the burner. Draw the wicking through by means of a metal hook. Trim the wick as close as
possible to the top of the burner with a pair of sharp scissors. It is essential that thoroughly cleaned burners and new wicking be
used for each test.
8. Control of Combustion
8.1 Most types of liquid samples burn with a luminous yellow flame, the size and shape of which is dependent on the gas flow
to the burner, the volatility of the material, the tightness of the fit of the wick in the burner tube, and the position of the top of the
Fleisher Methyl Purple Indicator, U. S. Patent No. 2416619 may be obtained from Harry Fleisher Chemical Co., Benjamin Franklin Station, Washington, DC 20044, or
from any chemical supply company handling Fleisher Methyl Purple.
D1266 − 18
TABLE 1 Sample Size for Direct Combustion of Liquid Samples
Sulfur Content, Sample Size
mass percent
g mL
Under 0.05 10 to 15 20
0.05 to 0.4 5 to 10 10
wick relative to the top of the burner. It is preferable that the latter two variables be fixed with relation to the first before burning
is started so that the flame can be controlled by variation in the rate of CO -O–O flow.
2 2
8.2 Highly volatile samples require a tight-fitting wick, the top of which can need to be several millimetres below the top of
the burner, and in extreme cases may have to be cooled in ice during the burning. Less volatile materials require a more loosely
fitting wick and can require warming.
8.3 After trimming, draw the wick down until the trimmed edge is flush with or just a little below the top of the burner. With
the burner for aromatic samples, the distance from the top of the burner to the top of the wicking should be 8 mm 8 mm or more
for benzene and 4 mm for toluene; a slight heating of the upper end of the burner will be helpful in starting vaporization of heavier
materials.
8.4 To use the standard lamp, light the wick and then slowly admit combustion atmosphere to the burner to obtain a smoke-free
flame. To use the burner for aromatic samples, introduce a small amount of combustion atmosphere into the flask to provide
sufficient vapor for lighting the burner. After lighting the burner, introduce combustion atmosphere directly into the burner to
prevent smoking and to adjust the flame size. If the flame is accidentally snuffed out, relight.
8.5 A short burning period (1(1 min to 2 min 2 min is usually sufficient) at low flame height is necessary to allow combustion
to reach equilibrium before the flame size can be increased without causing a smoky flame. In adjusting the standard lamp, the
entire control is at the burner. For the burner for aromatic samples, first adjust the flow of gas to the flask and then reduce the flow
of gas to the burner as required. In any case, it is essential that the flame burn smoothly and symmetrically and without jets in the
inner cone or smoke on the outer fringes.
8.6 Satisfactory combustion of materials difficult to burn can sometimes be obtained by increasing the O content of the
combustion atmosphere. Never increase the O content of the combustion atmosphere to more than 40 %.
8.7 Before extinguishing the flames, allow the sample to burn until the flask and wicking appear to be dry and the flame has
reduced considerably in size; frequently the flame continues to burn a short time after the flask appears dry because of the sample
in the wick. For example, for gasoline samples, which burn with a high flame, the flame should be extinguished when it is only
33 mm to 4 mm 4 mm high. If the flame is permitted to burn until it goes out, partially oxidized substances (probably organic acids)
are produced; as a result broad, indistinct end points are obtained. When samples are not burned until the flask is apparently dry,
erratic results may be obtained. In the case of volatile samples, any unburned sample will escape from the burner during weighing.
When elemental sulfur is present, it is particularly important that the sample be burned to apparent dryness and that the wick be
maintained flush with the top of the burner to ensure complete combustion. With mixtures containing light and heavy
hydrocarbons, the more volatile materials seem to burn first, possibly concentrating sulfur compounds in the material remaining
behind.
9. Procedure for Direct Combustion of Liquid Samples (see also Annex A2)
9.1 By means of an appropriate pipet, introduce into the flask of each lamp an approximate quantity of sample as indicated in
Table 1. Stopper the flasks with clean, numbered corks. Weigh each flask and its burner to the nearest 0.005 g.0.005 g.
NOTE 6—While the stoppered flasks and prepared burners can all be weighed separately, it is usually more convenient to place each flask and its burner
on the balance pan and obtain the combined weight in a single weighing.
9.2 Handling each lamp individually, insert the burner in the flask. As soon as the sample has risen by capillary action to the
top of the wick, connect the side tube of the burner to the burner manifold by means of sulfur-free rubber tubing. Light the burner
with a sulfur-free flame (such as an alcohol lamp) and insert into the chimney, pinching off the connection between the chimney
and the chimney manifold during the insertion if the flame tends to be blown out. At the same time, adjust the gas flow to the burner
so that the flame is maintained at a point just below smoking and has a steady symmetrical appearance. Continue in this manner
until all lamps have been placed in the chimneys. Make any minor adjustment of the chimney manifold control valve necessary
to maintain the required pressure (see Section 7). During the burning, and particularly during the latter stages when the flame
becomes small, decrease the CO -O–O supply to the burners in order to prevent extinction of the flames.
2 2
NOTE 7—When incomplete combustion occurs, the absorber liquid will foam excessively.
9.3 When the burning of each sample is complete, as evidenced by the flame becoming small owing to depletion of the sample,
remove the burner and flask from the chimney, extinguish the flame, shut off the CO -O–O supply to the burner and stopper the
2 2
chimney opening. Immediately reweigh the flask, burner, and numbered cork. When all combustions have been completed, turn
off the CO and the O supplies, close the chimney control valve, and close the connection to the vacuum regulator; this will cause
2 2
D1266 − 18
TABLE 2 Sample Size for Testing Blended Liquid Samples
Sulfur Content, Sample Size
mass percent
g mL
0.4 and under 3 to 4 5
air to be drawn into the chimney manifold through the manometer. Allow air to be drawn through the absorbers in this manner
for 5 min 5 min to remove dissolved CO from the absorbent; then close the vacuum control valve.
NOTE 8—If it is desired to conserve the combustion atmosphere, the gas flow through each individual absorber can be turned off upon completion of
the burning period. To accomplish this, pinch off the rubber tubing connecting the spray trap to the vacuum manifold, reduce the flow of mixed gases
at the rotameters proportionately, and readjust the vacuum control valve and the chimney control valve. When the burning of all samples has been
completed, it is necessary to remove the pinch clamps and readjust the vacuum control valve in order to draw air at the required rate through the absorbers
for removal of dissolved CO .
9.4 Rinse the chimneys and spray traps three times, using about 10 mL of water each time. When the sample contains lead
anti-knock fluids, use hot water to rinse the chimneys. Add the rinsing to the absorbers, and titrate as directed in Section 11.
9.5 Blank—Leave the chimney of the blank absorber (see 7.37.4) stoppered, and allow the CO -O–O stream to pass through
2 2
that absorber until all samples started at one time have finished burning. Turn off the CO and the O supplies and aerate the blank
2 2
absorber in the same manner as the sample absorbers (see 9.3). Titrate the absorber liquid as directed in Section 11. Normally, the
combustion atmosphere blank will be small, but if the titration requires more than 0.1 mL 0.1 mL of 0.05 0.05 N NaOH solution
discard the determination and replace the CO cylinder.
10. Procedure for Blending and Combustion of Liquid Samples
10.1 Add 6 mL 6 mL of sulfur-free diluent to each flask. Stopper the flasks with numbered corks and weigh to the nearest 0.005
g. 0.005 g. By means of a pipet, introduce into the flask of each burner an approximate quantity of sample as indicated in Table
2; swirl to mix thoroughly, and reweigh.
NOTE 9—Alternatively, make a quantitative 40 % blend of the sample in sulfur-free diluent and proceed as described in Section 9.
10.2 Insert the burner and burn as described in 9.2. Remove each lamp from its chimney as the flame nears extinction and
extinguish the flame. Add 2 mL 2 mL of diluent, allowing the diluent to rinse down the walls of the flask. Burn the additional
diluent and repeat the addition of diluent and burning one more time so that a total of 10 mL 10 mL of diluent has been burned.
NOTE 10—In this case, it is desirable that a 10-mL10 mL diluent blank be run; the titration of the absorber solution from this blank, shall not exceed
0.1 mL 0.1 mL of 0.05 0.05 M NaOH solution.
10.3 After all lamps have completed burning, turn off the CO and O supplies, close the connection to the vacuum regulator,
2 2
draw air through the absorbers for 5 min, 5 min, and finally close the vacuum control valve. Rinse the chimneys and spray traps
three times, using about 10 mL 10 mL of water each time. Add the rinsings to the absorbers, and titrate as directed in Section 11.
11. Titration of Absorbent Solution
11.1 Add 3 to 4 drops of methyl purple indicator solution to the liquid in each absorber. Titrate the absorbent solution by
introducing 0.05 0.05 N NaOH solution from a buret into the smaller bulb of the absorber. Use a 10-mL microb
...