A Highly Sensitive Method for the Determination of Thiophanate Methyl, Cyromazine, and Their Metabolites in Edible Fungi by Ultra-Performance Liquid Chromatography Using Accelerated Solvent Extraction and Cleanup with Solid-Phase Extraction

A highly sensitive ultra-performance liquid chromatographic method with diode-array detection was developed for residue determination of thiophanate methyl (TM), cyromazine (CYR), and their metabolites, carbendazim (MBC) and melamine (MEL). Edible fungi samples were treated using accelerated solvent extraction (ASE) followed by cleanup with solid-phase extraction (SPE). Under optimized conditions, good linearity was achieved with a correlation coefficient (r(2)) of >= 0.9998. The limit of quantification was 0.36, 0.24, 0.4, and 0.5 mu g kg(-1) for MEL, CYR, MBC, and TM, respectively. The intra- and interday precisions (in terms of the relative standard deviation (RSD)) of the four analytes were in the range of 2.3-4.5 and 3.1-6.3 %, respectively. The recoveries for TM, MBC, CYR, and MEL in four edible fungi samples at three spiked levels of 0.6, 6, and 20 mu g kg(-1) for TM and MBC and 0.4, 4, and 20 mu g kg(-1) for CYR and MEL were in the range of 82-105 % with RSDs below 5.6 %. The proposed method can be used for the routine determination of CYR and MEL in edible fungi with high sensitivity and accuracy as well as low consumption of reagents.