A sensitive immunochromatographic assay using colloidal gold-antibody probe for the rapid detection of semicarbazide in meat specimens

A rapid immunochromatographic assay (ICA) was developed for the detection of semicarbazide (SEM), a nitrofurazone metabolite in meat specimens. Colloidal gold-labeled monoclonal antibody specific to a SEM derivative, 4[(4-carboxyphenyl)methylene]-hydrazinecarboxamide (CPSEM), was used as a probe for the presence of SEM. The assay is based upon the competitive reactivity theory that SEM derivatized with 4-carboxybenzaldehyde (4-CBA) competes with CPSEM-conjugated bovine serum albumin for binding the colloidal gold-labeled monoclonal antibody, the result of which could be read directly by naked eyes. Under optimal conditions, the visual detection limit is 0.72 ng mL(-1), which demonstrated the high sensitivity of this assay. The stability test indicated that the immunochromatographic strips could be used within 7 weeks at room temperature without significant loss of activity. Spiked pork samples were detected by ICA and confirmed by enzyme-linked immunosorbent assay (ELISA). The assay time for SEM detection was within 5 min, suitable for a rapid on-site testing for meat samples.