15. Report
15.1 Report the result as the total sulfur content in mg/kg rounding to one decimal place using Practice E29, and state that the results were obtained in accordance with Test Method D7212.
16. Precision and Bias
16.1 The precision and bias were obtained by statistical analysis of results from an interlaboratory study involving nine laboratories using six gasoline samples and six diesel fuel samples. An additional sample, a certified reference material of diesel fuel ERML-EF6736 with 52.4 mg/kg sulfur, was supplied as a calibration check sample (see 11.3.2).
16.2 Precision - The precision of this test method is as follows:
16.2.1 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 value only in one case in twenty, where X equals the test result:
16.2.2 Reproducibility - The difference between two single and independent test 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 value only in one case in twenty, where X equals the test result:
16.2.3 Calculated examples of repeatability (r) and reproducibility (R) are given in Table 3.
16.3 Bias - A certified reference material of diesel fuel, ERML-EF674 with 11.0 mg/kg sulfur was included as a test sample in the interlaboratory test results. There was no significant bias.
17. Keywords
17.1 analysis; automotive fuels; energy dispersive; low background; low sulfur; spectrometry; X-ray