ASTM D5441 Standard Test Method for Analysis of Methyl Tert-Butyl Ether (MTBE) by Gas Chromatography
15. Precision and Bias
15.1 Precision - The precision of any individual measurement resulting from the application of this test method is expected to be dependent upon several factors including volatility of the component, its concentration and the degree to which it is resolved from other closely eluting components. Since it is not practical to determine the precision for measurement of every component separated by this method, Table 3 lists repeatability and reproducibility for selected representative components.
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 method, exceed the values calculated from the equations listed in Table 3 only in one case in twenty. Table 4 lists typical values for repeatability over the concentration ranges of interest calculated from the equations in Table 3.
15.1.2 Reproducibility - The difference between two single and independent test results obtained by different operators working in different laboratories on identical test materials would, in the long run, in the normal and correct operation of the test method, exceed the values calculated from the equations listed in Table 3 only in one case in twenty. Table 4 lists typical values for repeatability over the concentration ranges of interest calculated from the equations in Table 3.
15.2 Bias - Bias in the measurements resulting from the application of this test was calculated for selected compounds since it is not practical to determine bias for all compounds separated by this method. The calculations were made using the interlaboratory study results for a gravimetrically prepared blend of all of the compounds in Table 3 except for isobutylene. The calculations were accomplished using RR:D02-1007. No significant bias was observed.
16. Keywords
16.1 methyl tert-butyl ether; MTBE; open tubular column gas chromatography
