Development and diffusion of practical technologies for pesticide residue analysis.

We often encounter difficulties in analyzing pesticide residues in food, since the residue level to be measured is infinitesimal but the food samples may contain a variety of matrices, including interferences, for chromatographic analysis. Thus it is important to find out the key points to be checked in the extraction, purification, and determination steps of analysis. We have attempted to develop practical technologies for the analysis of pesticide residues in raw agricultural commodities based on the following studies: The effect of processing and cooking on pesticide residue levels in several crop samples (rice, wheat, soybean, and sesame) was investigated. The processing factor is useful to estimate the amount of exposure to each pesticide residue for risk assessment and is helpful in setting the maximum residue limits of processed foods. In addition, residue levels in the peel and pulp of watermelon, melon, and kiwi fruit samples were examined to confirm the differences in the distribution of residues. As a basic study, the effect of water-soaking pretreatment of powdered dry cereal on extraction efficiency was examined, and an optimal time for water-soaking was found. A recent study examined the ability of several new types of solid-phase extraction columns to remove matrices in brown rice samples and verified the effective purification method for each sample.