title: Development of a QuEChERS-Based Method for the Simultaneous Determination of Acidic Pesticides, Their Esters, and Conjugates Following Alkaline Hydrolysis.
abstract: An analytical procedure was developed allowing the simultaneous determination of acidic pesticides and their conjugates by addition of an alkaline hydrolysis step into the European Union (EU) version of the QuEChERS method. The procedure resulted additionally in hydrolysis of most esters of phenoxy acids. On the basis of information from metabolism studies and the hydrolytic conditions employed in supervised field trials as well as results on the influence of physical and chemical parameters (temperature, time, type of solvent, type of matrix), alkaline hydrolysis for 30 min at 40 °C was deemed a good compromise for the determination of residues of 2,4-D, dichlorprop, fluazifop, haloxyfop, MCPA, and MCPB. The applicability of the proposed method was tested by analyzing food samples with incurred residues in six German laboratories not involved in method development. Up to 6 times higher residues are measured by using the QuEChERS extraction procedure with the newly developed alkaline hydrolysis step.
authors.affiliation: Federal Institute for Risk Assessment , Department of Pesticides Safety, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany.
authors.forename: Angelika
authors.identifier: http://orcid.org/0000-0002-8904-2690
authors.initials: A
authors.lastname: Steinborn
authors.affiliation: Federal Institute for Risk Assessment , Department of Pesticides Safety, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Alder
authors.affiliation: Federal Office of Consumer Protection and Food Safety (BVL), National Reference Laboratories for Pesticide Residues , Diedersdorfer Weg 1, 12277 Berlin, Germany.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Spitzke
authors.affiliation: EU-Reference Laboratory for Residues of Pesticides Requiring Single Residue Methods (EURL-SRM), hosted at the Chemisches und Veterinäruntersuchungsamt Stuttgart , Schaflandstrasse 3/2, 70736 Fellbach, Stuttgart, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Dörk
authors.affiliation: EU-Reference Laboratory for Residues of Pesticides Requiring Single Residue Methods (EURL-SRM), hosted at the Chemisches und Veterinäruntersuchungsamt Stuttgart , Schaflandstrasse 3/2, 70736 Fellbach, Stuttgart, Germany.
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Anastassiades
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D004952:Esters / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000032:analysis; D006868:Hydrolysis; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D000097:Acetonitriles; D004952:Esters; D010573:Pesticide Residues; D010575:Pesticides; D012997:Solvents; C032159:acetonitrile
keywords: EU reference method; LC-MS/MS; QuEChERS method; acidic pesticides; alkaline hydrolysis