Estimation of uncertainty of sample preparation for the analysis of pesticide residues

The sampling constant and testing method proposed by Ingamells and Switzer, and Wallace and Kratochvil were used for estimating the uncertainty of sample preparation of apples and head-cabbages. The sampling constants' of about 1.6 kg and 10-20 kg were determined for cabbage and apple, respectively. Consequently about 64 g cabbage and 440-880 g apples should be extracted for holding the uncertainty of sample preparation less than or equal to 5%.