7. Calculation
7.1 Calculate the sulfur content of the sample as follows:
Sulfur, weight percent = (P - B)13.73/W
where:
P = grams of BaSO4 obtained from sample,
B = grams of BaSO4 obtained from blank, and
W = grams of sample used.
8. Report
8.1 Report the results of the test to the nearest 0.01 %.
9. Precision and Bias
9.1 The precision of this test is not known to have been obtained in accordance with currently accepted guidelines (for example in Research Report D02-1007).
9.1.1 Repeatability - The difference between two 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 in one case in twenty.
9.1.2 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:
NOTE 7 - The precision shown in the above table does not apply to samples containing over 2 % chlorine because an added restriction on the amount of sample which can be ignited is imposed.
NOTE 8 - This test method has been cooperatively tested only in the range of 0.1 to 5.0 % sulfur.
NOTE 9 - The following information on the precision of this method has been developed by the Institute of Petroleum (London):
(a) Results of duplicate tests should not differ by more than the following amounts:
where x is the mean of duplicate test results.
(b) These precision values were obtained in 1960 by statistical examination of interlaboratory test results.13 No limits have been established for
additive concentrates.
9.2 Bias - Results obtained in one laboratory by Test Method D129 on NIST Standard Reference Material Nos. 1620A, 1621C, and 1662B were found to be 0.05 mass % higher than the accepted reference values.
10. Quality Control
10.1 Confirm the performance of the instrument or the test procedure by analyzing a QC sample (see 5.9).
10.1.1 When QC/Quality Assurance (QA) protocols are already established in the testing facility, these may be used to confirm the reliability of the test result.
10.1.2 When there is no QC/QA protocol established in the testing facility, Appendix X1 can be used as the QC/QA system.
11. Keywords
11.1 bomb; sulfur