Development of a lateral flow immunoassay for the detection of total malachite green residues in fish tissues

We developed a sensitive lateral flow immunoassay (LFI) for the detection of total malachite green (MG) residues in fish tissues. LFI was based on a colloidal gold nanoparticle-labeled monoclonal antibody against MG , which was generated by fast immunization of carboxymalachite green-bovine serum albumin. The half-maximum inhibition concentration (IC50) of MG monoclonal antibody (MG mAb) was 0.057 ng/ml with a linear range of 0.020–0.162 ng/ml. Following the optimization of LFI, a qualitatively visual limit of detection of 1 ng/ml and a semi-quantitatively limit of detection of 0.418 ng/ml (IC50 of the calibration curve) were obtained for total MG residues in 8 min. Cross-reactivity with most MG analogs was negligible, expect with crystal violet (CV; 78.6% cross-reactivity). LFI is a novel and sensitive assay based on MG mAb that has applications for the rapid detection of total MG and CV in fish products.