Rapid Determination of Phenoxy Acid Herbicide Residues in Textiles by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry
A simple and efficient method for rapid determination of 7 phenoxy acid herbicide residues in textiles,based on the use of liquid chromatography electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS),is reported. Sample treatment procedure entailing the use of twice ultrasonic extraction steps with acetone(acidified by formic acid) without any clean-up was developed. A reversed-phase C18 column with an aqueous ammonium acetate/methanol mixture as the mobile phase was used under gradient elution. Mass spectral acquisition was done in negative ion mode by applying selected reaction monitoring(SRM). Two isotopic fragmentation transitions per compound were used to provide a high degree of selectivity. The method was in-house validated in terms of limit of detections(LODs),limit of quantitations(LOQs),linearity,recovery,precision on three typical kinds of textiles. Good results in the low μg/kg level were obtained for LODs and LOQs of all analytes in matrices. Extraction recoveries for 7 phenoxy acid herbicides ranged from 85% to 106% and RSD was between 2%-11%. The method fulfils Oeko-Tex Standard 100 demands for routine monitoring and verification of phenoxy acid herbicides.