Abstract
This experiment was conducted to establish an analytical method for residues of amisulbrom, as recently developed an oomycete-specific fungicide showing inhibition of fungal respiration, in crops using HPLC-UVD/MS. Amisulbrom residue was extracted with acetonitrile from representative samples of five raw products which comprised apple, green pepper, kimchi cabbage, potato and hulled rice. The extract was diluted with 50 mL of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice sample, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, amisulbrom was successfully separated from sample co-extractives and sensitively quantitated by ultraviolet absorption at 255 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery test on every crop samples fortified with amisulbrom at 3 concentration levels per crop in each triplication. Mean recoveries ranged from 85.3% to 105.6% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of amisulbrom was 0.04 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue. The proposed method was sensitive, reproducible and easy-to-operate enough to routinely determine the residue of amisulbrom in agricultural commodities.
HPLC-UVD/MS를 이용하여 농산물 중 sulfonamide계 살균제 amisulbrom의 잔류 분석법을 확립하였다. 대표 농산물은 사과, 배추, 고추, 감자 및 현미로 선정하였고, acetonitrile을 가하여 추출된 amisulbrom 성분을 dichloromethane 액-액 분배법과 Florisil 흡착크로마토그래피법으로 정제하여 HPLC-UVD/MS 분석대상 시료로 하였다. Amisulbrom의 정량적 분석을 위한 최적 HPLC 분석 조건을 확립하였으며, 정량한계(LOQ)는 0.04 mg/kg이었다. 각 대표 농산물에 대해 정량한계, 정량한계의 10 및 50배 수준에서 회수율을 검토한 결과 모든 처리농도에서 85.3-105.6% 수준을 나타내었으며, 반복 간 변이계수(CV)는 최대 6.3%를 나타내어 잔류분석 기준인 회수율 70-120% 및 분석오차 10% 이내를 충족시키는 만족한 결과를 도출하였으며, LC/MS SIM을 이용하여 실제 농산물 시료에 적용하여 재확인 하였다. 이상의 결과로 신규 amisulbrom의 HPLC-UVD/MS 분석법은 검출한계, 회수율 및 분석오차 면에서 국제적 분석기준을 만족하는 신뢰성이 확보된 정량 분석법으로 사용 가능할 것이다.
