Development of analytical method for fenamidone residues in horticultural crops using HPLC-UVD/MS

This experiment was conducted to establish an analytical method for residues of fenamidone, such as imidazole fungicide, in horticultural crops using HPLC-UVD/MS. Fenamidone residue was extracted with acetone from representative samples of four horticultural crops which comprised apple, green pepper, kimchi cabbage, and cucumber. The extract was purified by optimized dichloromethane liquid-liquid partition and florisil column chromatography. On an octadecylsilyl column in HPLC, fenamidone was successfully separated from co-extractives of sample, and limit of quantitation (LOQ) of fenamidone was 0.04 mg·kg-1 as verified by the recovery experiment. Mean recoveries ranged from 85.5% to 97.9% in four representative horticultural crops. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue. The proposed method can be used as a reliable quantitative analytical method that accepts international analytical criteria in terms of analytical sensitivity, reproducibility, ease of operation, recovery rate, and analysis error.