10. Calculation and Report
10.1 Calculate the sodium concentration, in parts per million as follows:
Sodium, mg in sample = [(A - B) x CE]/1000D
Sodium, mg/kg = (mg of sodium x 1000)/W
where:
A = sodium concentration of the sample solution, mg/L,
B = sodium concentration in the reagent blank, mg/L,
C = volume to which ashed sample was originally diluted, mL,
D = volume of aliquot taken from original dilution, mL
E = volume to which aliquot D was diluted, mL and
W = weight of sample used, g,
10.2 Report the results to the nearest 1 mg/kg.
11. Precision and Bias
11.1 Precision - The following criteria should be used for judging the acceptability of results (95 % confidence):
11.1.1 Repeatability - The difference between successive test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test 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:
11.1.2 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:
11.2 Bias - Since there is no accepted reference material suitable for determining the bias for the procedure in this test method, no statement on bias is being made.