Efficiency of Silver Ion-Silica Solid Phase Extraction for Elimination of Sulfur Compounds during Pesticide Multiresidue Analysis in Allium Species

Abstract

Since organic sulfur compounds respond to GC/ECD sensitively, they interfere with quantitative separation of pesticides during residual pesticide analysis of Allium species. In this study, it was intended to develop a rapid and simple method for pesticide multi-residues analysis through clean-up and interferences by a solid-phase extraction (SPE). An SPE method employing silver nitrate impregnated Florosil cartridge was developed and evaluated for the elimination of sulfur compounds from the test solution of Allium species during pesticide residues analysis. The silver nitrate impregnated Florosil cartridge was prepared by efflux of 3 ml of 20% silver nitrate solution through Florosil cartridge (1 g packing, 6 ml tube). The extracts equivalent to 2, 4 6, and 10 g of each sample were loaded onto the cartridge and allowed to exude, and then the exudations were analyzed by GC/ECD. More than 95% of sulfur compounds were removed from the loaded extracts equivalent, up to 6 g in onion, 4 g in spring onion and 4 g in shallot, respectively. 40 pesticides were spiked in the Allium species and loaded onto the cartridge to determine the recoveries; from this, the recoveries of 34 pesticides were within 70～120%.

Marine Natural Products: The Important Resource of Biological Insecticide

“…Structural uniqueness gives marine natural products an advantage in insecticide development. Currently, many highly effective commercial insecticide products are dominated by chemically synthesized halides, sulfides, and nitrides [20–24] . A large number of marine natural products have these elements themselves, which is rare in land natural products [25–29] .…”