Validation of Multiresidue Screening Methods for the Determination of 186 Pesticides in 11 Agricultural Products Using Gas Chromatography (GC)

Validation of multiresidue screening methods for the determination of 186 pesticides in 11 agricultural products: broccoli, asparagus, carrot, spinach, burdock, matsutake mushroom, cauliflower, orange, soybean, sesame and millet was done by gas chromatography (GC). The investigated pesticides were selected on the based of such compounds that are commonly used around the world. Although the recovery of 58 of the pesticides was low (< 50%) in some crops, the 128 pesticides that spiked in samples at 0.1 mg/kg showed satisfactory recoveries (≥ 50%) in all crops with relative standard deviation of 4-21%. These validated 128 pesticides were therefore newly acceptable for the pesticide-monitoring programme at the Quarantine Station in Japan; the quantitative limits ranged from 0.005 to 0.1 ppm by GC on a crop basis. The screening methods were applied to monitor the residue from a total of 200 pesticides including 72 previously validated in imported foods at the Station in Japan. Pesticide residue from 188 (12.4%) was found in 1516 samples. Of these, 4 (0.26%) were in violation of Japanese maximum residue limits (MRLs). No detectable residue was found in 1328 (87.6%) samples.