Multiresidue Analysis for Agricultural Chemicals in Edible Salts by LC/MS

Abstract

A multiresidue analytical method based on solid phase extraction with LC/MS was developed for agricultural chemicals in edible salts. For the extraction of agricultural chemicals from salt samples, a sample solution prepared at pH 3.5 was passed through a styrene-divinylbenzene, methacrylate copolymer cartridge that was preconditioned with 10% EDTA solution. The recovery rate was more than 70%, and the relative standard deviations were lower than 20%. The solvent of the eluate was changed from acetonitrile to a mixture of 80% water and acetonitrile, which resulted in sharp peaks in LC chromatograms. Benomyls were degraded during the extraction procedure, but they could be quantified as total benomyls and their degraded chemicals. The quantification limit for all the agricultural chemicals tested in edible salts was less than 0.01 mg/kg. Thirty-three agricultural chemicals could be analyzed by the present LC/MS method. If both the GC/MS method reported previously and the present LC/MS method were applied to the 162 agricultural chemicals selected by the Salt Industry Center of Japan and found in edible salts, 128 agricultural chemicals could be analyzed.