ASTM D2549 Separation of Representative Aromatics and Nonaromatics Fractions
ASTM D2549 Standard Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution Chromatography
10. Precision and Bias
10.1 The following criteria should be used for judging the acceptability of results (95 % probability):
10.1.1 Repeatability - The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 0.4 weight % for 10 g of sample; and 1.4 weight % for 2 g of sample.
10.1.2 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, and in the normal and correct operation of the test method, exceed the following values only in one case in twenty: 1.6 weight % for 10 g of sample; and 1.5 weight % for 2 g of sample.
NOTE 10 - The procedure for analyzing 2 g of sample gives recoveries of aromatics fractions that are on average 0.35 weight % lower than the procedure for analyzing 10 g of sample.
10.2 Bias - Bias cannot be determined because there are no reference materials suitable for determining the bias in this test method.
NOTE 11 - The precision of the procedure in Appendix X1 has not been determined.
11. Keywords
11.1 aromatics fraction; elution chromatography; high-boiling oils; nonaromatics fraction
