Designation: D1839 – 91 (Reapproved 2005)

Standard Test Method for

Amyl Nitrate in Diesel Fuels1
This standard is issued under the fixed designation D1839; 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 cetane number. This test method is applicable as a basis for

1.1 This test method covers the determination of 0.1 to 0.5 judging compliance with specifications covering amyl nitrate.
volume % amyl nitrate in diesel fuels. 5. Interferences
1.2 The values stated in SI units are to be regarded as the
standard. 5.1 Nitrate esters, inorganic nitrate ions, and nitrogen oxides
1.3 This standard does not purport to address all of the will interfere to give high results.
safety concerns, if any, associated with its use. It is the 6. Apparatus
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 6.1 Absorption Cells, matched, having a 1.000- 6 0.002-cm
bility of regulatory limitations prior to use. light path.
6.2 Distillate Collector,3 borosilicate glass with standard
NOTE 1—This test method has been used for the determination of hexyl taper joints and sealed-in funnel (Fig. 1).
nitrate in diesel fuels, but has not been cooperatively tested for such 6.3 Electric Heating Mantle, to fit a 300-mL round-bottom
samples. For the determination of hexyl nitrate, use standards containing
nitrate esters of primary hexanol. Use a density of 0.97 in calculating
flask, and having a variable transformer.
results. 6.4 Lunge-type Pipet, 2-mL capacity.
NOTE 2—A 2.5-mL hypodermic syringe, with scabbard, can be used
2. Referenced Documents instead of the Lunge pipet.
2.1 ASTM Standards:2 6.5 Reflux Condenser (Allihn-type), borosilicate glass, 300
D1193 Specification for Reagent Water mm long, with standard-taper joints.
D4057 Practice for Manual Sampling of Petroleum and
6.6 Round-Bottom Flask, of borosilicate glass and having a
Petroleum Products 300-mL capacity.
3. Summary of Test Method 6.7 Separatory Funnel, Squibb-type, 125-mL capacity.
6.8 Shaking Machine, automatic, capable of 250
3.1 This test method is based on the simultaneous hydroly-
oscillations/min.
sis of the ester in 62.5 % sulfuric acid and nitration of
6.9 Spectrophotometer, capable of measuring absorption in
m-xylenol by the nitric acid liberated. The nitroxylenol is
the region of 452 nm.
distilled from the reaction mixture and reacted with sodium
hydroxide to form the yellow sodium salt. Residual diesel fuel 7. Reagents
is removed by ether extraction. The color is measured spectro-
7.1 Purity of Reagents—Reagent grade chemicals shall be
photometrically at 452 nm, and the concentration of amyl
used in all tests. Unless otherwise indicated, it is intended that
nitrate is determined by reference to a standard curve.
all reagents shall conform to the specifications of the Commit-
4. Significance and Use tee on Analytical Reagents of the American Chemical Society,
where such specifications are available.4 Other grades may be
4.1 This test method can be used to determine the amount of
used, provided it is first ascertained that the reagent is of
amyl nitrate that has been added to diesel fuels to improve

3
The sole source of supply of the apparatus known to the committee at this time
1
This method is under the jurisdiction of ASTM Committee D02 on Petroleum is obtainable from Corning Glass Co., Corning, NY, Catalog No. 3320. If you are
Products and Lubricants and is the direct responsibility of Subcommittee D02.03 on aware of alternative suppliers, please provide this information to ASTM Interna-
Elemental Analysis. tional Headquarters. Your comments will receive careful consideration at a meeting
Current edition approved May 1, 2005. Published May 2005. Originally of the responsible technical committee 1, which you may attend.
approved in 1961. Last previous edition approved in 2000 as D1839 – 91 (2000)´1. 4
Reagent Chemicals, American Chemical Society Specifications, American
DOI: 10.1520/D1839-91R05. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar 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.

1
 D1839 – 91 (2005)
9. Preparation of Calibration Curve
9.1 Prepare a series of standard samples containing a known
amount of amyl nitrate in diesel fuel, covering the range of 0.2
to 2.0 mg of amyl nitrate per gram (Note 3). Weigh 0.5-g
portions of these standards, to the nearest 0.1 mg, into the
Squibb-type separatory funnels and treat as described in
Section 10. Calculate the milligrams of amyl nitrate in each
standard by multiplying the weight of the standard taken by the
corresponding concentration of amyl nitrate. Construct a cali-
bration curve by plotting absorbance values as the ordinate and
corresponding milligrams of amyl nitrate per 50 mL as the
abscissa.
NOTE 3—Experience with the method indicates that different base
stocks of diesel fuels do not cause variations in the results. If low results
are obtained for a particular fuel, prepare standards using the fuel in
question to check the reaction and recoveries.

10. Procedure
10.1 Weigh into a separatory funnel a sample of diesel fuel
to the nearest 0.1 mg, not exceeding 2 mL (Note 4), and not
containing more than 1.0 mg of amyl nitrate. Add 2 mL of the
m-xylenol solution and shake thoroughly. Add 50 mL of
H2SO4. Shake for 30 min on the automatic shaking machine.
Transfer the contents of the separatory funnel to the round-
bottom flask and wash the funnel with 100 mL of water,
FIG. 1 Distillation Apparatus combining this rinse with the solution in the flask.
NOTE 4—Incomplete reaction will take place if more than 2 mL of
sufficiently high purity to permit its use without lessening the sample is used.
accuracy of the determination. 10.2 With the apparatus assembled as shown in Fig. 1, distill
7.2 Purity of Water—Unless otherwise specified, references the sample into a 50-mL volumetric flask containing 5 mL of
to water shall be understood to mean reagent water as defined NaOH solution. Collect 40 mL of distillate. Cool, and dilute to
as Type II or III in Specification D1193. volume with water, allowing any floating diesel fuel to be
7.3 Acetone (Warning—Extremely flammable. Vapors can above the mark.
cause flash fire. Harmful if inhaled.).
7.4 Amyl Nitrate—Any mixture of nitrate esters of primary NOTE 5—When the solution is not yellow, check the pH. When it is not
alkaline, add additional NaOH solution.
amyl alcohol.
7.5 Diethyl Ether (Warning—Extremely flammable. Va- 10.3 Transfer the solution to a separatory funnel and extract
pors can cause flash fire. Harmful if inhaled.). with several portions of ether to remove the diesel fuel that
7.6 Sodium Hydroxide Solution (20 g/L)—Dissolve 20 g of otherwise would cause a turbid water layer.
sodium hydroxide (NaOH) pellets in water and dilute to 1 L. 10.4 Filter the water layer through a coarse-texture paper
7.7 Sulfuric Acid (5 + 3)—Slowly add, with stirring, 500 into an absorption cell and measure its absorbance at 452 nm
mL of nitrate-free concentrated sulfuric acid (H2SO4, rel dens with respect to water (Note 6). Subtract a blank (Note 7) from
1.84) to 300 mL of water. The m-xylenol solution must be the reading and read the milligrams of amyl nitrate from the
added before the H2SO4, otherwise low or negative results will calibration curve (Section 8).
be obtained. Cool before use. NOTE 6—The color developed is stable for several hours. It obeys
7.8 m-Xylenol Solution—Dilute 4 mL of m-xylenol (2,4- Beer’s law over the range from 0.2 to 2.0 mg of amyl nitrate.
dimethylphenol5) to 100 mL with acetone. Prepare fresh each NOTE 7—Obtain a blank by performing the analysis on the samples of
day. diesel fuel and the reagents without the amyl nitrate present. A blank of
0.019 absorbance can be used since it is the average obtained on a number
8. Sampling of representative diesel fuels.
8.1 Samples shall be taken in accordance with the appropri- 11. Calculation
ate instructions in Practice D4057.
11.1 Calculate the amyl nitrate present in the sample as
follows:
5
The sole source of supply of the apparatus known to the committee at this time Amyl nitrate, mass % 5 100A/1000W 5 A/10W (1)
is obtainable from Eastman Kodak Co., Rochester, NY, Reagent No. 1150. If you are Amyl nitrate, vol % 5 BD/C (2)
aware of alternative suppliers, please provide this information to ASTM Interna-
tional Headquarters. Your comments will receive careful consideration at a meeting
where:
of the responsible technical committee 1, which you may attend.

2
 D1839 – 91 (2005)

A = milligrams of amyl nitrate obtained from the calibra- 0.10 volume % (3)
tion curve, 12.1.2 Reproducibility—The difference between two single
B = mass % of amyl nitrate obtained from Eq 1, and independent results obtained by different operators work-
C = density of amyl nitrate (0.998 at 20°C),
ing in different laboratories on identical test material would in
D = density of diesel fuel sampled at 20°C, and
W = grams of sample used. the long run, in the normal and correct operation of the test
method exceed the following values only in one case in twenty:
12. Precision and Bias 6 0.10 volume % (4)
12.1 Precision—The precision of this test method as ob-
12.2 Bias—The bias of this test method cannot be deter-
tained by statistical analysis of interlaboratory test results is as
follows: mined since an appropriate standard reference material con-
12.1.1 Repeatability—The difference between successive taining a known level of amyl nitrate in diesel fuel is not
test results, obtained by the same operator with the same available.
apparatus under constant operating conditions on identical test
material would, in the long run, in the normal and correct 13. Keywords
operation of the test method exceed the following value only in 13.1 amyl nitrate; diesel fuel; nitroxylenol;
one case in twenty: spectrophotometric

6
There is no existing research report for this test method.

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