Immunoaffinity chromatography for purification of Salbutamol and Clenbuterol followed screening and confirmation by ELISA and GC-MS

Screening and confirmatory methods for the determination of Salbutamol (SAL) and Clenbuterol (CL) in swine urine were established. The polyclonal antibody against SAL was prepared, which was used to develop the indirect competitive enzyme-linked immunosorbent assay (ELISA) with the limit of detection of 0.5 ng/ml, and to prepare the immunoaffinity chromatography column. The immunoaffinity column could extract and purify SAL and CL simultaneously, with a binding capacity of 400 ng for SAL and 416 ng for CL. After purification, the swine urine samples were screened by ELISA for the presence of SAL and/or CL, and the positive samples were further confirmed and quantified by gas chromatography-mass spectrometry (GC-MS). The results showed that 95% of the positive samples were confirmed by GC-MS with various levels of SAL (1.1-4.6 ng/ml) and/or CL (1.9-229.1 ng/ml) residues in the incurred samples, and all the negative samples were confirmed with no SAL and/or CL residues.