Evaluation of the errors of sample taking, sample preparation, and analysis in complicated procedures of control over the composition of precious metals

摘要

A procedure for the experimental determination of a precious metal in a lot of raw materials is considered. In this procedure, a sample taken from the lot is divided into several portions differing in the concentration of the precious metal, a separate sample is prepared from each portion, and the mass fraction of the precious metal in the lot is determined after chemical analysis by the results of analysis of several samples. Equations are derived that allow the random error arising at the stages of sampling (sample taking and sample preparation) to be separated from the total random error of sample taking, sample preparation, and analysis of several samples. Thus, the random errors of sampling that previously have not been taken into account can be revealed. Among those, the errors arising in sample taking dominate.