Detection of multi-β-agonist residues in liver matrix by use of a surface plasma resonance biosensor Original Research Article

The abuse of growth promoting β-agonist drugs in animal production remains a problem in many parts of the world. Evidence exists that suggests the range of compounds being abused has become more varied over the past number of years. Detection of a wide family of drugs at low concentrations in complex biological matrices poses significant analytical difficulties. The present study outlines a novel approach to overcome some of these problems by using a high-affinity, broad-spectrum β-agonist monoclonal antibody in an immuno-biosensor assay based on surface plasmon resonance. The assay was capable of analysing 16 liver samples for multi-β-agonists residues within 1.5 days. Liver sample preparation involved proteolytic digestion, enzymatic deconjugation and solid-phase extraction using Oasis™ cartridges. The resultant extracts were mixed with the antibody prior to being injected for 2 min over a clenbuterol coated sensor chip. The sensor surface was regenerated using 0.1 M NaOH. In total, inclusive of washing procedures, etc., it took 10 min for the biosensor to analyse a single sample. The detection limit of the assay was determined according to the guidelines laid down for screening assay validation in the recently revised version of EC Directive 96/23. The assay was able to detect mabuterol (MBL) down to 0.02 ng g−1, clenbuterol at 0.11 ng g−1 and salbutamol at 0.19 ng g−1. A wide range of other β-agonists were also detected at concentrations below 1.5 ng g−1.