Establishment of Analytical Method for Napropamide Residue in Korean Cabbage, Green Pepper, Apple, Mandarin, Potato and Soybean Using HPLC and LC-MS/MS

Abstract

This study was performed to develop a precise single residue analytical method of herbicide napropamide in representative crops for general residue analytical methods using HPLC and LC-MS/MS which could be applied to most of crops. Analytical steps of napropamide residue as follows : Korean cabbage, green pepper, apple, mandarin, potato and soybean were selected, macerated, extracted with acetone, concentrated and partitioned with n-hexane. Then it was concentrated and cleaned-up through Florisil column with ethyl acetate/n-hexane (20:80, v/v) before concentration and analysis with HPLC-UVD. LOQ (Limit of Quantification) of napropamide was 5 ng (S/N>10) and MLOQ (Method Limit of Quantitation) was 0.05 mg/kg. Recoveries were measured at three fortification levels (MLOQ, 10MLOQ and 100MLOQ) on crop samples and ranged 85.2-105.4% (mean recoveries) and coefficients of variation were <10% regardless of sample type. In order to development of analytical method using LC-MS/MS, the QuEChERS method was chosen for sample preparation. LOQ of napropamide was 0.05 ng and MLOQ was 0.01 mg/kg in QuEChERS-LC-MS/MS method. Recoveries were measure at two fortification levels (MLOQ and 10MLOQ) were reasonable (71.7-106.7%) and coefficients of variation were 1.4-11.9% at Korean cabbage, green pepper, apple, mandarin, potato and soybean.