LC-MS/MS를 이용한 배 중 티오파네이트메틸 및 대사체 동시 분석 = Simultaneous Determination of Thiophanate-methyl and its Metabolite in Pear using Liquid Chromatography-Tandem Mass Spectrometry

다국어 초록 (Multilingual Abstract)

Thiophanate-methyl is used as systemic fungicide with broad-spectrum activity, and is used to control various fungal pathogens such as Venturia nashicola and Glomerella cingulate in pear, apple, and paprika. Pear is one of the most common fruits in Republic of Korea and other Asian countries, and in 2016, it is the crop with the highest yields followed by apple and the production amounted to about 23,000 tons in Korea. In the open field, pear fruits can be easily attacked by plant pathogens at a suitable temperature. However it is difficult for farmers to maintain an environment such as temperature and humidity. For this reason, the application of pesticides should be considered to reduce workforce and cut losses in fruit production. For safety of consumers, an analytical method was developed to quantify the residual levels of the thiophanate-methyl and its metabolite in field-incurred pear samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were extracted with methanol and clean-up with C18 QuEChERS bulk sorbent. Linearity of a matrix-matched calibration curve of the thiophanate-methyl and carbendazim over a concentration range of 0.005-0.5 μg/mL and 0.001-0.1 μg/mL, respectively, was excellent, with determination coefficients (R²) ≥ 0.9990. The limits of detection (LOD) and quantitation (LOQ) for thiophanate-methyl and carbendazim were 0.0015 and 0.005 mg/kg, and 0.0003 and 0.001 mg/kg, respectively. The average recoveries of two analyte at two spiking levels (10 × LOQ and 50 × LOQ) were between 75.00 to 84.92%, with relative standard deviations (RSDs) ≤ 5.78%. The method was successfully applied to field-incurred samples treated with a commercial pesticide product. The treatments were divided into four treatments according to the days before harvest and sprayed four times following schedule: (treatment 1) 70, 60, 50 and 40 days before harvest; (treatment 2) 60, 50, 40 and 30 days before harvest; (treatment 3) 50, 40, 30 and 21 days before harvest; (treatment 4) 40, 30, 21 and 14 days before harvest. The highest and lowest residues were obtained for treatment 4 and treatment 2, respectively. The developed method is simple and accurate and can be extrapolated to other fruits.