PESTICIDE ENVIRONMENT CHEMISTRY : High - Performance Liquid Chromatographic Determination of Tricyclazole Residues in Rice Grain , Rice Straw , and Soil

An analytical method was developed to determine tricyclazole residues in rice grain, straw, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Tricyclazole was extracted with methanol from moist rice grain, straw, and soil samples. n-Hexane washing was employed to remove nonpolar co-extractives during liquid-liquid partition. Tricyclazole was then extracted with dichloromethane from alkaline aqueous phase, while acidic interferences remained in the phase. Dichloromethane extract was further purified by silica gel column chromatography prior to HPLC determination. Reverse-phase HPLC using an octadecylsilyl column was successfully applied to separate and quantitate the tricyclazole residue in sample extracts monitored at λ_(max) 225 nm. Recoveries from fortified samples averaged 95.5 ± 3.0% (n=6), 87.5 ± 2.0% (n=6), and 84.3 ± 2.8% (n=12) for rice grain, straw, and soil, respectively. Detection limit of the method was 0.02 ㎎/㎏ for rice grain and soil samples while 0.05 ㎎/㎏ for rice straw samples. The proposed method was reproducible and sensitive enough to evaluate the safety of tricyclazole residues in rice grain, straw, and soil.