ASTM D6729 Method for Individual Components in Spark Ignition Engine Fuels
ASTM D6729 Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100 Metre Capillary High Resolution Gas Chromatography
13. Precision and Bias
13.1 The repeatability and reproducibility precision estimates are quoted in Annex A1.
13.2 Precision Statement Outline - (> Analyte Qualification Process):
13.2.1 For each analyte to qualify for a precision statement, it must be present in at least six samples, and detected by at least six laboratories, at least once, in accordance with RR:D02-1007 requirements.
13.2.2 The (repeatability standard deviation)/mean value for each analyte/sample combination must be less than or equal to 0.1, in accordance with LOQ requirements which, while not a standard, is what CS94 is recommending.
13.3 A brief explanation of headers in Table A1.2 follows:
13.3.1 ID: self explanatory,
13.3.2 Rmin: lower 95 % confidence limit of Rest,
13.3.3 Rest: repeatability estimate in percentage of concentration,
13.3.4 Rmax: upper 95 % confidence limit of rest,
13.3.5 Rmin, Rest, Rmax: same as above except for reproducibility,
13.3.6 Cmin: lower concentration limit that rest, Rest is applicable, and
13.3.7 Cmax: upper concentration limit that rest, Rest is applicable.
13.4 The summaries for the paraffins, isoparaffins, C2 benzene, and oxygenates follow the same procedure that was used for the analytes and are listed in Table A1.3.
13.5 Bias - The bias of this test method cannot be determined since an appropriate standard reference material is not available.
14. Keywords
14.1 gas chromatograph; gasoline; individual hydrocarbon analysis; oxygenated fuels; spark-ignition engine fuels
