Abstract
The present study was performed to investigate the pre-harvest residue limit (PHRL) of pesticides namely, metalaxyl-M and flusilazole in oriental melon, and to identify the biological half-life and characteristics of their residues. In this study, pesticides were sprayed once as single spray and double spray on oriental melon. The oriental melon samples were collected at 0, 1, 2, 3, 5, 7, 9 and 11 days before harvest and samples were extracted with QuEChERS method. The residues of both the pesticides were quantified using GC/NPD and LC/MS/MS. The limit of detection was found to be 0.02 mg/kg and 0.01 mg/kg and their recoveries were greater than 95% (95.7% ~ 103.2% for metalaxyl-M and 100.2% ~ 106.8% for flusilazole) for both pesticides. The biological half-lives of both metalaxyl-M and flusilazole were 12 days at single and double spray, respectively. The PHRL of metalaxyl-M and flusilazole was found 1.0 mg/kg and 0.3 mg/kg, respectively for 10 days before harvest. The results of the present study shows the residual level of both the pesticides metalaxyl-M and flusilazole in oriental melon were less than their maximum residual limits.
본 연구는 참외에 대한 살균제 metalaxyl-M과 flusilazole의 잔류량 변화를 측정하여 약제별 잔류특성을 파악하고, 반감기를 산출함으로써 생산단계 잔류허용기준(PHRL, Pre-Harvest Residue Limit) 설정을 위한 기초자료로서 활용하고자 수행하였다. 공시 약제인 metalaxyl-M과 flusilazole은 안전사용기준에 준하여 7일 간격으로 1회, 2회살포하였으며, 살포 2시간 후를 0일차로 하여 0, 1, 2, 3, 5, 7, 9, 11일차에 수확하였고, 잔류량의 경시변화 결과를 토대로 생물학적 반감기를 산출하였다. 시료는 QuEChERS방법을 이용하여 전처리하였으며, metalaxyl-M의 경우 GC/NPD를 이용하여 분석하였으며, flusilazole은 LC/MS/MS를 이용하여 분석하였다. 참외 중 metalaxyl-M과 flusilazole의 LOQ (Limit of quantitation)는 각각 0.02 mg/kg, 0.01 mg/kg이었으며, metalaxyl-M 회수율은 95.7-103.2%이었고, flusilazole은 100.2-106.8%이었으며, 표준편차는 모두 10% 미만이었다. 참외 중 각 농약에 대한 생물학적 반감기는 flusilazole의 경우 1, 2회 처리구에서 12일이었으며, metalaxyl-M의 경우 23일이었다. 본 연구결과, metalaxyl-M 및 flusilazole의 수확 10일 전 PHRL은 각각 1.5, 0.3 mg/kg로 나타났으며, 수확 시 metalaxyl-M, flusilazole의 잔류농도는 MRL을 초과하지 않을 것으로 예측되었다.
