Analytical Method Development of Paraquat, Diquat, Chlormequat and Mepiquat in Meat, Milk and Eggs by LC-MS/MS

Analysis of Quats in Meat, Milk and Eggs by LC-MS/MS

Abstract

        Paraquat is a type 4 hazardous substance that has been banned for manufacturing, import, export, transit, or possession according to the Notifi cation of the Ministry of Industry No. 6 (B.E. 2563) Re: List of Hazardous Substances. Additionally, the Notifi cation of the Ministry of Public Health No. 419 (B.E. 2563) Re: Food Containing Pesticide Residues indicates the criteria for regulating paraquat level in meat, milk and eggs that the analytical method used for detection must have a minimum  detection limit of 0.005 mg/kg. Based on these notifications, an efficient laboratory was developed using LC-MS/MS to simultaneously determine paraquat and three quats; diquat, chlormequat and mepiquat in meat, milk and eggs. Samples were extracted using acidic acetonitrile, centrifuged, purifi ed through hydrophilic-lipophilic-balanced (HLB) SPE cartridge and quantify using multiple reaction monitoring (MRM). The method had a limit of detection (LOD) and quantifi cation (LOQ) of 0.005 mg/kg and 0.01 mg/kg, respectively, with a linearity range of 0.01–0.20 mg/kg and accuracy (%recovery) at 64.8–108.6 and precision (%RSD) at 2.1–13.0. This method was used to analyze 29 food samples and it was found no quat residues. Therefore, this developed method is effective for determining quat residues in meat, milk, and eggs and suitable for monitoring quat residues in food regulations.