[An experimental proficiency test for ability to screen 104 residual pesticides in agricultural products].

An experimental proficiency test program for ability to screen 104 residual pesticides in agricultural products has been conducted. Eight Japanese laboratories joined the program. Items tested in the present study were limit of detection, internal proficiency test (self spike) and external proficiency test (blind spike). All 104 pesticides were well detected and recovered from agricultural foods in the internal proficiency test. However, the results of the external proficiency test did not completely agree with those of the internal proficiency tests. After 5 rounds of the blind spike test, the ratio of the number of correctly detected pesticides to that of actually contained ones (49 total) ranged from 65% to 100% among laboratories. The numbers of mistakenly detected pesticides by a laboratory were 0 to 15. Thus, there was a great difference among the laboratories in the ability to screen multiresidual pesticides.