Phenoxy Alkanoic Acids in Milk Using Modified QuEChERS Method Version 1 (last update: 10.04.14) Compound details The group of Phenoxy herbicides is subdivided in Phenoxyacetic herbicides (e.g. 4-CPA, 2,4-D, MCPA, 2,4,5-T) Phenoxybutyric herbicides (e.g. 2,4-DB, MCPB) Phenoxypropionic herbicides (e.g. dichlorprop, fenoprop, mecoprop) Aryloxyphenoxypropionic herbicides (e.g. diclofop, fluazifop, haloxyfop, quizalofop) altogether 49 different compounds [4]. As representatives of the group the following four herbicides were validated for milk. 2,4-D Haloxyfop O N O F OH Cl O OH Cl O F F O Cl Dichlorprop Fluazifop O N O F OH Cl O OH O F F O Cl Residue definition (commodity group AO): 2,4-D (sum of 2,4-D and its esters expressed as 2,4-D) Dichlorprop: sum of dichlorprop (including dichlorprop-P) and its conjugates, expressed as dichlorprop Fluazifop-P-butyl (fluazifop acid (free and conjugate)) Haloxyfop including Haloxyfop-R: Haloxyfop-R and conjugates of haloxyfop-R expressed as haloxyfop-R EU Reference Laboratory for Pesticides Requiring Single Residue Methods Page 1 CVUA Stuttgart, Schaflandstr. 3/2, 70736 Fellbach, Germany
[email protected] Extraction method: Analysis is performed applying QuEChERS extraction: Weigh 10 g milk, add 10 mL acetoni- trile, shake 15 min. (GenoGrinder), add citrat-salt mix, shake 1 min. (GenoGrinder), centri- fuge --> raw extract, As expected, the acidic phenoxy alkanoic acids show reduced recoveries when a PSA clean- up is performed: Mean recovery in % (0.1ppm) Compound after PSA-cleanup 2.4-D 47 2.4-DP (Dichlorprop)