ASTM D2268 Test Method for Analysis of High-Purity n-Heptane and Isooctane by Capillary Gas Chromatography
10. Precision and Bias
10.1 The precision of this test method as determined by statistical examination of interlaboratory results is as follows:
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, in the normal and correct operation of the test method, exceed the following values only one case in twenty:
0.010 volume % at levels > 99.5 volume %.
10.1.2 Reproducibility - The difference between two single and independent results obtained by different opera-tors 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 one case in twenty:
0.054 volume % at levels > 99.5 volume %.
10.2 The above precision values are based on cooperative data from seven laboratories using five samples. Calculations were performed using peak area. Both electronic integration and triangulation were employed.
10.3 Since there are no acceptable reference test methods for comparison, no statement of bias can be made.
11. Keywords
11.1 ASTM knock test reference fuels; capillary column; gas chromatography; isooctane; n-Heptane
