title: Trace analysis of endectocides in milk by high performance liquid chromatography with fluorescence detection.
abstract: An analytical method has been developed for the simultaneous determination of the following endectocide drugs in milk: ivermectin, abamectin, doramectin, moxidectin, eprinomectin, emamectin and nemadectin. Samples were extracted with acetonitrile, purified with solid-phase extraction on a reversed phase C(8), derivatised with N-methylimidazole, trifluoroacetic anhydride and acetic acid to a stable fluorescent derivative, and were further analysed by gradient high performance liquid chromatography (HPLC) on an endcapped reversed phase Supelcosil LC-8-DB. The derivatisation step was mathematically optimised and the method was validated according to the requirements of Commission Decision 2002/657/EC, using fortified raw bovine milk. Mean recovery was between 78 and 98%. The repeatability (CV(r)) and within-laboratory reproducibility (CV(W)) ranged from 4.6 to 13.4% and from 6.6 to 14.5%, respectively. Decision limits (CCalpha) for analytes with MRL values, namely eprinomectin and moxidectin, were determined to be 24.8 and 50.6 microg kg(-1), respectively. CCalpha values for unauthorised endectocides ranged from 0.1 to 0.2 microg kg(-1). Due to high acceptability regarding the required criteria and applicability to ovine and caprine milk, giving similar results, this multi-analyte method has been successfully implemented in pharmacokinetic research studies as well as statutory residue monitoring in Slovenia.
authors.affiliation: Veterinary Faculty of University of Ljubljana, Gerbiceva 60, SI-1000 Ljubljana, Slovenia. vesna.cerkvenik.flajs@siol.net
authors.forename: Vesna
authors.initials: V
authors.lastname: Cerkvenik-Flajs
authors.forename: Luka
authors.initials: L
authors.lastname: Milcinski
authors.forename: Adica
authors.initials: A
authors.lastname: Süssinger
authors.forename: Lena
authors.initials: L
authors.lastname: Hodoscek
authors.forename: Martin
authors.initials: M
authors.lastname: Danaher
authors.forename: Jan
authors.initials: J
authors.lastname: Antonić
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D007306:Insecticides / Q000032:analysis*; D008892:Milk / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis*; D015203:Reproducibility of Results; D052616:Solid Phase Extraction
chemical_list: D000097:Acetonitriles; D007306:Insecticides; D010573:Pesticide Residues; C032159:acetonitrile