ASTM D1840 Test Method for Naphthalene Hydrocarbons in Aviation Turbine Fuels
ASTM D1840 Standard Test Method for Naphthalene Hydrocarbons in Aviation Turbine Fuels by Ultraviolet Spectrophotometry
13. Report
13.1 Numerical values of volume percent naphthalene are reported to the nearest 0.01 %.
14. Reference Spectra
14.1 Absorptivities of individual naphthalene hydrocarbons at 285 nm are derived from data in the API catalog of ultraviolet spectral data issued by Research Project 44 as given in Table 3.
NOTE 7 - The arithmetic average of the above absorptivities is 33.7. The reliability of the average absorptivity as a measure of selected individual naphthalenes can be estimated from the above table.
15. Precision and Bias
15.1 Precision - The precision of this test method was determined by the statistical examination of interlaboratory test results. The precision for Procedure A was determined based on examination of interlaboratory test results for samples covering the range from 0.03 to 4.25 volume % napthalenes. The precision for Procedure B was determined based on examination of interlaboratory test results for samples covering the range from 0.08 to 5.6 volume % napthalenes. The precisions are as follows:
15.1.1 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty.
Repeatability for Procedure A = 0.0222 (1.00 + X)
Repeatability for Procedure B = 0.056 X(0.6)
where:
X = average of two results, volume %.
15.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method exceed the following values only in one case in twenty.
Reproducibility for Procedure A = 0.0299 (1.00 + X)
Reproducibility for Procedure B = 0.094 X(0.6)
where:
X = average of two results, volume %.
NOTE 8 - Instruments not conforming to the equipment specifications in 7.1 can result in much poorer precision.
15.2 Bias - Bias cannot be determined for the procedure in this test method for measuring naphthalene hydrocarbon because the absorptivity will vary with composition of the individual naphthalene derivatives in samples.
16. Keywords
16.1 aviation turbine fuels; naphthalene hydrocarbons; ultraviolet spectrophotometry
