• Benzimidazole carbamate residues in milk: Detection by Surface Plasmon Resonance-biosensor, using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method for extraction

      Keegan, Jemma; Whelan, Michelle; Danaher, Martin; Crooks, Steven; Sayers, Riona; Anastasio, Aniello; Elliott, C.; Brandon, David; Furey, A.; O'Kennedy, Richard (Elsevier, 2009-09-26)
      A surface plasmon resonance (SPR) biosensor screening assay was developed and validated to detect 11 benzimidazole carbamate (BZT) veterinary drug residues in milk. The polyclonal antibody used was raised in sheep against a methyl 5(6)-[(carboxypentyl)-thio]-2-benzimidazole carbamate protein conjugate. A sample preparation procedure was developed using a modified QuEChERS method. BZT residues were extracted from milk using liquid extraction/partition with a dispersive solid phase extraction clean-up step. The assay was validated in accordance with the performance criteria described in 2002/657/EC. The limit of detection of the assay was calculated from the analysis of 20 known negative milk samples to be 2.7 μg kg−1. The detection capability (CCβ) of the assay was determined to be 5 μg kg−1 for 11 benzimidazole residues and the mean recovery of analytes was in the range 81–116%. A comparison was made between the SPR-biosensor and UPLC–MS/MS analyses of milk samples (n = 26) taken from cows treated different benzimidazole products, demonstrating the SPR-biosensor assay to be fit for purpose.
    • A dual validation approach to detect anthelmintic residues in bovine liver over an extended concentration range

      Kinsella, Brian; Whelan, Michelle; Cantwell, Helen; McCormack, Martin; Furey, A.; Lehotay, Stephen J.; Danaher, Martin; Department of Agriculture, Food and the Marine, Ireland; European Union; 06RDTAAFRC479; et al. (Elsevier, 21/08/2010)
      This paper describes a method for the detection and quantification of 38 residues of the most widely used anthelmintics (including 26 veterinary drugs belonging to the benzimidazole, macrocyclic lactone and flukicide classes) in bovine liver using two different protocols for MRL and non-MRL levels. A dual validation approach was adopted to reliably quantify anthelmintic residues over an extended concentration range (1–3000 gkg−1). Sample extraction and purification was carried out using a modified QuEChERS method. A concentration step was included when analysing in the low gkg−1 range. Rapid analysis was carried out by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS), which was capable of detecting residues to <2 gkg−1. The method has been single-laboratory validated according to the 2002/657/EC guidelines and met acceptability criteria in all but a few cases. The inclusion of 19 internal standards, including 14 isotopically labelled internal standards, improved accuracy, precision, decision limit (CC˛) and detection capability (CCˇ).