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

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 C(18) 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.