Simple and Rapid Determination of Cypermethrin and Fenvalerate Residues in Kampo Products by Gas Chromatography-Mass Spectrometry with Negative Chemical Ionization

Abstract

In Japan, crude drugs that are used as ingredients of kampo formulae are mainly imported from China. In China, cypermethrin and fenvalerate, which are pyrethroid pesticides, are detected frequently in food exported to Japan. In fact, cypermethrin and fenvalerate have been detected in crude drugs distributed in Japan. There is concern that cypermethrin and fenvalerate will move from crude drugs to kampo products. Cypermethrin and fenvalerate in kampo products are controlled by a self-imposed residual pesticide limit set by the Japan Kampo Medicine Manufacturers Association. Several methods to analyze cypermethrin and fenvalerate in kampo products have been reported, but they are time-consuming, require expensive column clean-up, and use large amounts of organic solvents. In this study, a simple, rapid, and inexpensive sample preparation method was developed to determine cypermethrin and fenvalerate levels in kampo products by gas chromatography (GC)-mass spectrometry (MS) with negative chemical ionization (NCI). Twenty-two samples of kampo products were analyzed according to the proposed method. No samples were contaminated by cypermethrin and fenvalerate levels greater than the detection limit.