시금치에서 살충제 Etoxazole과 Cartap hydrochloride의 잔류양상

Pesticides help in increased yield of agricultural products by controlling pests, pathogens and weeds, but threaten food safety if used incorrectly. Therefore, it is necessary to establish the ‘safe use standards’ for pesticide application to allow pesticide residues be in safe limit. In this study, residual patterns of etoxazole and cartap hydrochloride were investigated in spinach. Etoxazole (10%, SC) and cartap hydrochloride (50%, SP) were diluted 4,000 and 1,000 times, respectively, and sprayed twice with 7 days interval at 21, 14, 10, 7, 3 and 0 days before harvest. Residual amounts of etoxazole and cartap hydrochloride were analyzed by LC-MS/MS. The recovery test was conducted at two levels (0.01 and 0.1 mg/kg), and the recovery rate was 80.8~112.4% with the standard deviation of ≤ 5.8. For cartap hydrochloride, the residual amounts of nereistoxin were analyzed and converted to calculate total residue. The residue of etoxazole decreased from 1.39 mg/kg to 0.01 mg/kg with the reduction rate 99.3% at 21 days after application. On the other hand, cartap hydrochloride (including converted residual amount of nereistoxin) showed 71.3% reduction from 1.72 mg/kg to 0.49 mg/kg. Etoxazole decreased faster than cartap hydrochloride because cartap hydrochloride is converted to nereistoxin prior to decreasing. As each of the pesticides behaves differently in different plant matrics, it is important to know the residue pattern separately to ensure safe application. Hence, the findings of this study will help to establish the safe use standards for field application as well as MRLs for spinach for these two pesticides.