13. Report
13.1 Report the total sulfur concentration in parts per million by mass (mg/kg) to the nearest 0.1 mgS/kg.
14. Precision and Bias
14.1 Precision - The precision of this test method as determined by statistical examination of interlaboratory test results are as follows:
NOTE 5 - The following precision data were developed in a 2002 interlaboratory cooperative test program. Nine participants analyzed sample sets of blind duplicates of 16 types of hydrocarbons and hydrocarbon-oxygenate blends. The sample set consisted of eight gasoline samples and eight diesel samples. For the gasoline sample set, the concentration range was approximately from 3 to 100 mgS/kg and for the diesel sample set, approximately between 2 to 85 mgS/kg. To facilitate the calibration of the analyzers involved in the interlaboratory study, a calibration standard was provided for gasoline and a second calibration standard was provided for diesel. By providing calibration standards the uncertainty often introduced in the calibration process by variations in the standards was removed. By providing the calibration standards for each fuel tested, the precision could have been positively influenced.
14.1.1 Repeatability - The difference between two successive results obtained by the same operator with the same apparatus under constant operating conditions on identical test materials would, in the long run, in normal and correct operation of the test method exceed the following values only in one case in twenty:
14.1.2 Reproducibility - The difference between two single and independent results obtained by different operators working in different laboratories with different apparatus on identical materials would, in the long run, in normal and correct operation of the test method exceed the following values only in one case in twenty:
For repeatability and reproducibility estimates at several sulfur levels, see Table 3.
15. Keywords
15.1 flame photometric detector; gas chromatography; total sulfur