Determination of Phenoxy Acid Herbicides in Cereals Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry

An effective method for determination of multiple residues of phenoxy acid herbicides in cereals was developed. A QuEChERS (quick, easy, cheap, effective, rugged, and safe) technique coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was optimized for the analysis of phenoxy acid herbicides in rice, corn, and wheat. The limits of detection in the experiment were 0.0500 mu g/kg for 4-(2,4-dichlorophenoxy) acetic acid, (4-chloro-2-methylphenoxy) acetic acid, (2,4,5-trichlorophenoxy) acetic acid, and 2-(2,4-dichlorophenoxy) propionic acid and 0.300 mu g/kg for 4-(2,4-dichlorophenoxy) butyric acid and 3,6-dichloro-2-methoxybenzoic acid. The relative standard deviation of intraday and interday precision for the six phenoxy acid herbicides was less than 6.61%, and accuracy was 96.3 to 107%. Extraction recovery for phenoxy acid herbicides was 73.8 to 115%, with relative standard deviations of less than 12.1% at three spiking levels (1.00, 4.00, and 20.0 mu g/kg). These results indicate that QuEChERS sample preparation with HPLC-MS/MS analysis is a rapid, reliable, highly sensitive, and specific tool for the determination of phenoxy acid herbicide residues in cereals.