ASTM D3341-05(2011)
(Test Method)Standard Test Method for Lead in GasolineIodine Monochloride Method
Standard Test Method for Lead in Gasoline<char: emdash>Iodine Monochloride Method
SIGNIFICANCE AND USE
This test method determines the concentration of lead alkyl additives in gasoline. These additives improve the antiknock properties.
SCOPE
1.1 This test method determines total lead in gasolines containing lead alkyls at concentrations between 0.026 and 1.3 g Pb/L, and 0.12 and 6.0 g Pb/UK gal, 0.1 and 5.0 g Pb/US gal.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.2.1 The preferred units are grams per litre although both gram per US gallon and grams per UK gallon are acceptable due to their widespread use in the industry.
1.2.2 Temperature is given in degrees Fahrenheit and degrees Celsius in this test method.
1.3 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. For specific hazard statements, see Sections 6 and 8.
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D3341 − 05(Reapproved 2011)
Standard Test Method for
Lead in Gasoline—Iodine Monochloride Method
This standard is issued under the fixed designation D3341; 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.
1. Scope as the dialkyl lead compounds. The aqueous extract is sepa-
rated from the gasoline and evaporated to low bulk to decom-
1.1 This test method determines total lead in gasolines
pose free iodine monochloride. Any organic matter present is
containingleadalkylsatconcentrationsbetween0.026and1.3
removed by oxidation with nitric acid, which also serves to
gPb/L,and0.12and6.0gPb/UKgal,0.1and5.0gPb/USgal.
convert the dialkyl lead compounds into inorganic lead com-
1.2 The values stated in SI units are to be regarded as
pounds.Theresidueisdissolvedindistilledwaterandbuffered
standard. No other units of measurement are included in this
to pH 5 using sodium acetate-acetic acid buffer. The lead
standard.
content of the buffered solution is determined by titration with
1.2.1 The preferred units are grams per litre although both
EDTA using xylenol orange as indicator.
gram per US gallon and grams per UK gallon are acceptable
due to their widespread use in the industry.
4. Significance and Use
1.2.2 Temperature is given in degrees Fahrenheit and de-
4.1 This test method determines the concentration of lead
grees Celsius in this test method.
alkyl additives in gasoline. These additives improve the anti-
1.3 This standard does not purport to address all of the
knock properties.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
5. Apparatus
priate safety and health practices and determine the applica-
5.1 Separatory Funnel,borosilicateglass,capacity250mL,
bility of regulatory limitations prior to use.Forspecifichazard
glass-stoppered with preferably an iodine flask type of neck.
statements, see Sections 6 and 8.
5.2 Erlenmeyer Flask, borosilicate glass, capacity 500 mL.
2. Referenced Documents
2.1 ASTM Standards:
6. Reagents and Materials
D1193Specification for Reagent Water
6.1 Purity of Reagents—Reagent grade chemicals shall be
D4057Practice for Manual Sampling of Petroleum and
used in all tests. Unless otherwise indicated, it is intended that
Petroleum Products
all reagents shall conform to the specifications of the Commit-
D6299Practice for Applying Statistical Quality Assurance
tee onAnalytical Reagents of theAmerican Chemical Society,
and Control Charting Techniques to Evaluate Analytical
where such specifications are available.
Other grades may be
Measurement System Performance
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
3. Summary of Test Method
accuracy of the determination.
3.1 A known volume of the sample is diluted with heavy
6.1.1 Commerciallyavailablereagentsmaybeusedinplace
distillate and shaken with aqueous iodine monochloride re-
of laboratory preparations when they conform to the specifi-
agent. Any tetraalkyl lead compounds present react with the
cations in 6.1.
iodine monochloride and are extracted into the aqueous phase
6.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean reagent water as defined
by Type III or Type IV of Specification D1193.
This test method is under the jurisdiction of ASTM Committee D02 on
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
D02.03 on Elemental Analysis.
Current edition approved May 1, 2011. Published August 2011. Originally
approved in 1974. Last previous edition approved in 2005 as D3341–05. DOI: Reagent Chemicals, American Chemical Society Specifications, American
10.1520/D3341-05R11. Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Annual Standards for Laboratory
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
Standards volume information, refer to the standard’s Document Summary page on and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
the ASTM website. MD.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3341 − 05 (2011)
6.3 Ammonia Solution (1 + 1)—Mix 1 volume of concen- distilledwater.Usingaburet,add6.2mLofglacialaceticacid.
trated ammonia solution (rel dens 0.90) with 1 volume of Dilute to 1 Lwith distilled water in a 1-Lvolumetric flask and
distilled water. shake to mix.
6.11 Xylenol Orange Indicator Solution— Dissolve 0.2 g of
6.4 Bromthymol Blue Indicator Solution—Dissolve0.1gof
xylenol orange, sodium salt, in 100 mL of distilled water and
bromthymol blue in 50 mL of ethanol and dilute to 100 mL
add 1 drop of 1+1 hydrochloric acid. (Prepare freshly each
with distilled water.
week.)
6.5 EDTA, Standard Solution (0.005 M)—Dissolveapproxi-
7. Sampling
mately3.75gofdiaminoethanetetra-aceticacid,disodiumsalt,
in2-Lofdistilledwater.Determinethemolarityofthesolution
7.1 Samples shall be taken in accordance with the instruc-
by standardization with lead nitrate solution as follows:
tions in Practice D4057.
6.5.1 Using a pipet, transfer 25.0 mL of the standard lead
8. Procedure
nitrate solution to a 250-mLErlenmeyer flask. Dilute to about
8.1 Transfer 50 mLof the iodine monochloride reagent and
75 mL with distilled water and add several drops of bromthy-
25 mL of heavy distillate to the 250-mL separatory funnel.
mol blue indicator solution. Titrate with 1+1 ammonia solu-
Measure the temperature of the sample to the nearest 0.5°C
tionuntilthecolorofthesolutionjustchangestoblue;thenadd
(1°F) (Note 1). Using a pipet Warning—(Never suck leaded
10mLofsodiumacetate-aceticacidbuffersolutionand5drops
gasoline or corrosive liquids into a pipet by the mouth),
ofxylenolorangeindicatorsolution.Inthepresenceofleadthe
transfer 25 6 0.05 mL of the sample of the gasoline to the
solutionwillhavearosecolor.TitratewiththeEDTAsolution.
separatory funnel. Immediately stopper the funnel and shake
Thecolorchangesneartheendpoint,thisbeingindicatedbya
the contents for 60 s. Allow the funnel to stand for several
sharpchangefromorangetoapermanentbrightlemon-yellow.
minutes,untilthetwophaseshaveseparatedandrunthelower
6.5.2 Record the titer and calculate the molarity of the
aqueous phase into a 500-mL Erlenmeyer flask made of
EDTA solution. The addition of excess EDTA produces no
borosilicate glass. Wash the gasoline phase by shaking with
further color change at the end point.
three separate 20-mL portions of distilled water and add the
6.6 Heavy Distillate—A straight-run, lead-free, petroleum
washings to the Erlenmeyer flask.
distillate of low bromine number, with approximately 10%
NOTE 1—For cool gasolines having a Reid vapor pressure above 7.0 lb
distilling at 400°F (205°C) and 90% at 460°F (240°C)
cool the sealed sample container to approximately 60°F (15°C) before
(Warning—Combustible).
removing the sample for analysis.
8.2 Placeseveralglassbeadsintheflask,coverthemouthof
6.7 Iodine Monochloride Reagent (1.0 M) (Warning—
the flask with a small ribbed watch glass, and place on a hot
Iodine monochloride will react with ammonium ions under
plate. Heat the contents and allow to boil until the volume of
certain conditions to yield nitrogen triiodide, which is explo-
the solution is 15 to 20 mL. Without removing the flask from
sive. Take care, therefore, that this reagent does not come into
the hot plate, add 5 mL of concentrated nitric acid down the
contactwithammoniaorammoniumsalts.)Dissolve111.0gof
side of the flask and evaporate the contents almost to dryness
potassium iodide (KI) in approximately 400 mL of distilled
to oxidize any organic material present. Repeat the nitric acid
water. Add 445 mL of concentrated hydrochloric acid (sp gr
treatment, evaporating almost to dryness until all the organic
1.18) and cool to room temperature. Add 75.0 g of potassium
matter has been removed and a white residue remains. Finally
iodate (KIO ) slowly and with stirring, until all the free iodine
remove the watch glass and evaporate the solution to dryness.
initially formed has just redissolved to give a clear orange-red
Remove the flask from the hot plate and allow the contents to
solution (the amounts of KI and KIO are calculated to give a
cool.
slight excess of iodate; if a greater excess is present, this will
cause precipitation of lead and indifferent end points in the
8.3 Add about 200 mL of distilled water to the flask and
EDTA titration). Cool to room temperature and dilute to 1 L
swirl to dissolve the residue.
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.