Development of colloidal carbon-based immunochromatographic strip for rapid detection of carbaryl in fruit juices

A simple immunochromatographic assay for sensitive detection of insecticide carbaryl in fruit juices was developed. The test is based on inhibition format on a nitrocellulose membrane strip. The strip was separately coated with rabbit anti-swine antibody (control line) and carbaryl hapten-OVA conjugate (test line). Colour intensity on the test line was possible to recognize visually from that of negative sample within 10 min, with the detection limit of 5 ng mL(-1). All characteristics of the visually evaluated strips were also measured quantitatively, and then the detection limit was 1.5 ng mL(-1). Cross-reactions with other carbamate pesticides were not found (< 1%). No matrix effects were observed when fruit juices (orange, apple, pear, banana) were diluted tenfold times before analyses. The results from immunochromatographical assay were in a good agreement with those obtained by enzyme-linked immunosorbent assay as reference method. All these facts indicate the potential of the immunochromatographic strip for the quality control of fruit juices.