• 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.
    • Detection of benzimidazole carbamates and amino metabolites in liver by surface plasmon resonance-biosensor

      Keegan, Jemma; O'Kennedy, Richard; Crooks, Steven; Elliott, C.; Brandon, David; Danaher, Martin; Department of Agriculture, Food and the Marine, Ireland; 05/R&D/TN/355 (Elsevier, 14/01/2011)
      Two surface plasmon resonance (SPR) biosensor screening assays were developed and validated to detect 11 benzimidazole carbamate (BZT) and four amino-benzimidazole veterinary drug residues in liver tissue. The assays used polyclonal antibodies, raised in sheep, to detect BZTs and amino-benzimidazoles. A modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction method was developed to isolate benzimidazole carbamate residues. Liver samples were extracted using an acetonitrile extraction method. BZTs were purified by dispersive solid phase extraction (d-SPE) using C18 sorbent. Residues of amino-benzimidazoles were effectively cleaned-up using a simple cyclohexane defatting step. The assays were validated in accordance with the performance criteria described in 2002/657/EC. The BZT assay limit of detection was calculated to be 32 μg kg−1, the detection capability (CCβ) was determined to be 50 μg kg−1 and the mean recovery of analytes was in the range 77–132%. The amino-benzimidazole assay limit of detection was determined to be 41 μg kg−1, the CCβ was determined to be 75 μg kg−1 and analyte recovery was in the range 103–116%. Biosensor assay performance was tested by analysing liver tissue from animals treated with benzimidazole drugs and comparing the results with an ultra high performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS) confirmatory method. All non-compliant samples were identified using the biosensor assays.