ASTM D4377-00(2011)
(Test Method)Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration (Withdrawn 2020)
Standard Test Method for Water in Crude Oils by Potentiometric Karl Fischer Titration (Withdrawn 2020)
SIGNIFICANCE AND USE
A knowledge of the water content of crude oil is important in the refining, purchase, sale, or transfer of crude oils.
SCOPE
1.1 This test method covers the determination of water in the range from 0.02 to 2 % in crude oils. Mercaptan and sulfide (S− or H2S) sulfur are known to interfere with this test method (see Section 5).
1.2 This test method is intended for use with standard Karl Fischer reagent or pyridine-free Karl Fischer reagents.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 7.
WITHDRAWN RATIONALE
This test method covers the determination of water in the range from 0.02 to 2 % in crude oils. Mercaptan and sulfide (S− or H2S) sulfur are known to interfere with this test method.
Formerly under the jurisdiction of Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants, this test method was withdrawn in January 2020 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4377 − 00 (Reapproved 2011)
Manual of Petroleum Measurement Standards (MPMS), Chapter 10.7
Designation: 356/99
Standard Test Method for
Water in Crude Oils by Potentiometric Karl Fischer Titration
This standard is issued under the fixed designation D4377; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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 2.2 API Standards:
MPMS Chapter 8.1Manual Sampling of Petroleum and
1.1 This test method covers the determination of water in
Petroleum Products (ASTM Practice D4057)
therangefrom0.02to2%incrudeoils.Mercaptanandsulfide
− MPMS Chapter 8.2Automatic Sampling of Petroleum and
(S or H S) sulfur are known to interfere with this test method
Petroleum Products (ASTM Practice D4177)
(see Section 5).
MPMSChapter10.2DeterminationofWaterinCrudeOilby
1.2 This test method is intended for use with standard Karl
Distillation (ASTM Test Method D4006)
Fischer reagent or pyridine-free Karl Fischer reagents.
3. Summary of Test Method
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
3.1 After homogenizing the crude oil with a mixer, an
standard.
aliquot of the crude, in a mixed solvent, is titrated to an
electrometric end-point using Karl Fischer reagent.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4.1 A knowledge of the water content of crude oil is
bility of regulatory limitations prior to use. Specific precau-
important in the refining, purchase, sale, or transfer of crude
tionary statements are given in Section 7.
oils.
2. Referenced Documents
5. Interferences
2.1 ASTM Standards:
5.1 A number of substances and class of compounds asso-
D1193Specification for Reagent Water
ciated with condensation or oxidation-reduction reactions in-
D4006Test Method for Water in Crude Oil by Distillation
terfere in the determination of water by Karl Fischer. In crude
D4057Practice for Manual Sampling of Petroleum and
oils, the most common interferences are mercaptans and
Petroleum Products
sulfides. At levels of less than 500 µg/g (ppm) (as sulfur) the
D4177Practice for Automatic Sampling of Petroleum and
interference from these compounds is insignificant. For more
Petroleum Products
informationonsubstancesthatinterfereinthedeterminationof
E203Test Method for Water Using Volumetric Karl Fischer
waterusingthe(KarlFischerreagent)titrationmethodseeTest
Titration
Method E203.
6. Apparatus
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and the API Committee on
6.1 Karl Fischer Apparatus, using electrometric end-point.
Petroleum Measurement, and is the direct responsibility of Subcommittee D02.02
A suggested assembly of the apparatus is described in Annex
/COMQ on Hydrocarbon Measurement for Custody Transfer (Joint ASTM-API).
Current edition approved June 1, 2011. Published August 2011. Originally
A2.
approved in 1984. Last previous edition approved in 2006 as D4377–00(2006).
DOI: 10.1520/D4377-00R11.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Published as Manual of Petroleum Measurement Standards. Available from
Standards volume information, refer to the standard’s Document Summary page on AmericanPetroleumInstitute(API),1220L.St.,NW,Washington,DC20005-4070,
the ASTM website. http://api-ec.api.org.
© Jointly copyrighted byASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, USAand theAmerican Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USA
D4377 − 00 (2011)
6.1.1 Presently there is available on the market commercial 7.4.2 Pyridine-Free Karl Fischer (one-component) reagent
Karl Fischer titration assemblies, some of which automatically diluted with xylene—Dilute three parts pyridine-free Karl
stop the titration at the end-point. Instructions for operation of Fischer (one-component) reagent (1 mL=5 mg water) to 1
these devices are provided by the manufacturer and not part xylene. Fresh Karl Fischer reagent must be used.
described herein.This test method is not intended for use with (Warning—See 7.4.1) Must be used with solvent in 7.6.2.
coulometric Karl Fischer titrators.
7.5 Methanol (anhydrous), Maximum 0.1% water but pref-
6.2 Mixer, to homogenize the crude sample. erably less than 0.05% water. (Warning—Flammable. Vapor
6.2.1 Non-Aerating, High-Speed, Shear Mixer, capable of harmful. May be fatal or cause blindness if swallowed or
meetingthehomogenizationefficiencytestdescribedinAnnex inhaled. Cannot be made nonpoisonous.)
A1. The sample size is limited to that suggested by the
7.6 Sample Solvent—Use 7.6.1 for standard Karl Fischer
manufacturer for the size of the probe.
reagent containing pyridine and 7.6.2 for pyridine-free Karl
6.3 Syringes: Fischer reagent.
6.3.1 Samples and base liquid are most easily added to the 7.6.1 Sample Solvent—Mix 40 mL of 1-ethylpiperidine, 20
titrationvesselbymeansofaccurateglasssyringeswithLUER mL of methanol, and 40 mL of Karl Fischer reagent in a
fittings and hypodermic needles of suitable length. The bores sealableglassbottle.Allowthismixturetositovernightbefore
of the needles used should be kept as small as possible, but adding 200 mL of xylene. Additional methanol may be
large enough to avoid problems arising from back pressure/ required in some cases for the proper function of the elec-
blocking whilst sampling. Suggested syringe sizes are as trodes. (Warning—see 7.3.)
follows: 7.6.2 Sample Solvent for Pyridine-Free Reagents—Mix 3
6.3.1.1 Syringe, 10 µL, with a needle long enough to dip parts chloroform to 1 part pyridine-free solvent using solvent
below the surface of the base solution in the cell during the part of two-component reagent (contains SO and odorless
standardization procedure (see Section 9). amine dissolved in methanol) and store in a sealable glass
6.3.1.2 Syringes, 2.5 mL, 5 mL, and 10 mL for crude oil bottle. An evaluation of a number of crude oils has demon-
samples (see Section 10). strated that xylene can be substituted for chloroform with no
6.3.1.3 Syringe, 20 mL or larger for sample solvent. apparent change in accuracy of this test method. (Warning—
Flammable. Vapor harmful.) (Also, see 7.4.1.)
7. Reagents and Materials
7.7 Xylene, reagent grade. Less than 0.05% water.
7.1 Purity of Reagents—Reagent grade chemicals shall be
7.8 Chloroform, reagent grade. (Warning—Harmful if in-
used in all tests. Unless otherwise indicated, it is intended that
haled or swallowed. Carcinogen (animal positive). Skin and
all reagents shall conform to the specifications of the Commit-
eye irritant. May produce toxic vapors if burned.
tee onAnalytical Reagents of theAmerican Chemical Society,
where such specifications are available. Other grades may be
8. Sampling and Test Samples
used, provided it is first ascertained that the reagent is of
8.1 Sampling,isdefinedasallthestepsrequiredtoobtainan
sufficiently high purity to permit its use without lessening the
aliquotrepresentativeofthecontentsofanypipe,tank,orother
accuracy of the determination.
system, and to place the sample into the laboratory test
7.2 Purity of Water—Unless otherwise indicated, references
container. The laboratory test container and sample volume
to water shall be understood to mean reagent water as defined
shallbeofsufficientdimensionsandvolumetoallowmixingas
by Type IV of Specification D1193.
described in 8.1.2.1.
7.3 1-Ethylpiperidine (99+percent). (Warning—Irritant.
8.1.1 Laboratory Sample—Only representative samples ob-
Flammable.) tainedasspecifiedinPracticeD4057(API MPMSChapter8.1)
andPracticeD4177(API MPMSChapter8.2)shallbeusedfor
7.4 Karl Fischer Reagents, Standard reagent containing
this test method.
pyridine (7.4.1) or pyridine-free reagent (7.4.2).
8.1.2 Test Samples—The following sample handling proce-
7.4.1 Karl Fischer Reagent Ethylene Glycol Monomethyl
dure shall apply in addition to those covered in 8.1.1.
Ether Solution, stabilized, containing pyridine, (1 mL=5 mg
8.1.2.1 Mixthetestsampleofcrudeoilimmediately(within
of water)—Fresh Karl Fischer reagent must be used. Must be
15 min) before analysis to insure complete homogeneity. Mix
used with solvent in 7.6.1.(Warning—Combustible. Harmful
the test sample at room temperature (25°C) in the original
if swallowed, inhaled, or absorbed through the skin.)
container.
NOTE 1—The sample should be mixed at room temperature (25°C) or
Thefollowingmixerswereusedinacooperativeprogramandhavebeenfound
less. Mixing of the sample should not increase the temperature of the
satisfactory for samples under 300 mL; Ultra Turrax Model TP 18/10, available
from Tekmar Co., P. O. Box 37202, Cincinnati, OH 45222; Brinkman Polytron sample more than 10°C, or a loss of water may occur. The type of mixer
ModelPT35,AvailablefromBrinkmanInstrumentsInc.,CantiaguRoad,Westbury, depends on the quantity of crude. Before any unknown mixer is used, the
NY 11590; and Kraft Apparatus Model S-25, SGA, Bloomfield, NJ.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not Pyridine-free Karl Fischer reagent and two-component solvent used in the
listed by the American Chemical Society, see Annual Standards for Laboratory cooperative program and found to be satisfactory are available from Crescent
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia ChemicalCo.,Inc.,1324MotorParkway,Hauppauge,NY11788underthenameof
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, Hydranal a registered trademark of Riedel Dehaen—Composite 5 and Hydranal—
MD. solvent.
D4377 − 00 (2011)
TABLE 1 Test Sample—% Water Content Based on Sample Size
immediately. Remove any solvent from the needle by wiping
Expected Water Sample Size, with a paper tissue and reweigh the syringe to 0.1 mg. Titrate
Content, % g
the water with Karl Fischer reagent as in 9.3.1.
0–0.3 5
0.3–1 2
9.4 Calculate the water equivalence of the Karl Fischer
1–2 1
reagent as follows:
F 5 W/T (1)
specifications for the homogenization test, Annex A1, must be met. The
where:
mixer must be re-evaluated for any changes in the type of crude, quantity
F = water equivalence of the Karl Fischer reagent, mg/mL,
of crude, or shape of the sample container.
W = water added, mg, and
(1)For small sample volumes, 50 to 500 mL, a non-
T = reagent required for titration of the added water, mL.
aerating, high speed, shear mixer is required. Use the mixing
time, mixing speed, and height above the bottom of the
9.5 Duplicate values of water equivalence should agree
container found to be satisfactory to AnnexA1. Clean and dry
within 2% relative. If the variation between the two titrations
the mixer between samples.
isgreaterthan2%relative,discardthecontentsofthetitration
vessel. Introduce a further portion of sample solvent into the
8.1.2.2 ThetestsamplesizeisselectedasindicatedinTable
vesselandrepeatthestandardizationprocedure.Ifthetitrations
1 based on the expected water content.
for two further portions of distilled water still vary by more
9. Calibration and Standardization
than 2%, it is likely that either the Karl Fischer reagent or the
sample solvent, or both, have aged. Replace these with fresh
9.1 Standardize the Karl Fischer reagent at least once daily.
reagents and repeat the procedure for calibration and standard-
9.2 Add enough solvent to the clean, dry titration vessel to
ization.
cover the electrodes. The volume of solvent depends on the
9.6 Determine and record the mean water equivalence
size of the titration vessel. Seal all openings to the vessel and
value.
start the magnetic stirrer for a smooth stirring action. Turn on
the indicating circuit and adjust the potentiometer to give a
10. Procedure
reference point with approximately 1 µA of current flowing.
Add Karl Fischer reagent in suitable amounts to the solvent to
10.1 Addthefreshsamplesolventtothetitrationvesseland
causetheneedletodeflectfromthereferencepoint.Atfirstthe
bring the solvent to end-point conditions as described in 9.2.
needle will deflect due to local concentration of the unreacted
10.2 Add the crude to the titration vessel immediately after
reagent about the electrodes but will fall back to near the
themixingstepdescribedin8.1.2.1usingoneofthefollowing
referencepoint.Astheend-pointisapproached,theneedlewill
methods:
fall back more slowly after each addition of Karl Fischer
10.2.1 Starting with a clean, dry syringe (10 or 5 mL), rinse
reagent. The end-point is reached when, after the addition of a
the syringe two times with the sample and discharge to waste.
single drop of reagent, the needle remains deflected at least 1
Withdrawtherequiredamountofsampleanddischargeanyair
µAfrom the reference point for at least 30 s. Swirl the titration
bubbles. Weigh the syringe to the nearest 0.1 mg. Inject the
vessel to dry the inside walls of the vessel. Add more Karl
sample into the titration vessel, clean the needle with a paper
Fischer reagent, if needed, until a steady end-point is reached
tissue, and reweigh the syringe. Titrate the sample until a
for at least 30 s.
steady end-point for at least 30 s is reached and record the
9.3 StandardizetheKarlFischerreagentwithdistilledwater
volume of Karl Fischer reagent to the nearest 0.01 mL (see
by one of the following methods: Note 2 and Note 4).
9.3.1 From a water filled weighing pipet or syringe previ-
NOTE 4—The solvent should be changed when the sample content
ously weighed to the nearest 0.1 mg, add 1 drop of distilled
exceeds2gof crude per 15 mLof solvent or when 4 mLof titrant per 15
water (about 20 mg) to the sample solvent at end-point
mL of solvent has been added to the titration vessel.
conditions and reweigh the syringe. Record the weight of the
10.2.2 For viscous crudes, add the sample to a clean, dry
water added.Titrate the water with Karl Fischer reagent added
dropperbottleandweighthebottleandcrude.Quicklytransfer
fromtheburetuntilasteadyendpointisreachedforatleast30
the required amount of sample to the titration vessel with the
s.Recordtothenearest0.01mLthevolumeoftheKar
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