ASTM D1364 for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
12. Report
12.1 For water concentrations below 0.5 %, report all results to 0.001 %. Two determinations which agree within 0.008 %, absolute, are acceptable for averaging (95 % confidence level).
13. Precision and Bias
13.1 Precision for Water 0.100 to 0.500 % by Weight - On the basis of an interlaboratory study in which one operator made duplicate determinations in each of eight different laboratories, on two days, on samples of acetone containing 0.118 and 0.406 % water and of methyl ethyl ketone containing 0.050 and 0.176 % water, the following criteria should be used for judging at the 95 % confidence level the acceptability of results on samples containing less than 0.5 % water:
NOTE 9 - Supporting documentation for this interlaboratory study is not available from ASTM Headquarters.
13.1.1 Repeatability - Two results, each the mean of duplicate determinations, obtained by the same operator should be considered suspect if they differ by more than 0.015 % absolute.
13.1.2 Reproducibility - Two results, each the mean of duplicate determinations, obtained by operator in different laboratories should be considered suspect if they differ by more than 0.027 % absolute.
13.2 Precision for Water 0.010 to 0.100 % by Weight - In another interlaboratory study, one operator in each of seven different laboratories, on two different days, made duplicate determinations on five randomly coded samples of hexyl acetate containing 0.015, 0.034, 0.052, 0.071, and 0.098 % water. One of the seven laboratories used three different equipment or procedural variations, or both, thereby making this, in effect, a nine interlaboratory study. The statistically designed study covered a variety of equipment, analytical methods, and reagents using the Karl Fischer chemistry.
13.2.1 Repeatability - Two results, each the mean of duplicate determinations, obtained by the same analyst should be considered suspect if they differ by more than 0.030 √x % absolute, where x is the average of two determininations.
13.2.2 Reproducibility - Two results, each the mean of duplicate determinations, obtained by analysts in different laboratories should be considered suspect if they differ by more than 0.060 √x % absolute, where x is the average of two determinations.
13.3 Bias - Bias cannot be determined for this test method because there is no available material having an accepted reference value. Refer to 8.1 and Note 5, Note 6, and Note 7 for factors that might influence test bias.
14. Keywords
14.1 Karl Fisher method; solvents; water content
