Development of a Fast ELISA for the Specific Detection of both Leucomalachite Green and Malachite Green

Malachite green （MG）, a dye, is an antifungal agent that has been used to treat and prevent fish diseases. It is metabo- lized into reduced leucomalachite green forms （LMG） that may reside in fish muscles for a long period, thus being harmful to human health. The aim of this study was to develop a competitive and direct enzyme-linked immunosorbent assay （ELISA） to detect MG and LMG specifically. The monoclonal antibody （mAb） to LMG was generated using a hybridoma technique. The obtained mAb showed good cross-reactivity （CR） to malachite green （MG）, but not to crystal violet （CV） and Brilliant Green （BG）. The mAb was used to develop a fast detecting ELISA of MG and LMG in fish. By introducing the conjugation LMG-HRP, the detection capability was 0.37ngmL-1 for MG and LMG. The mean recovery from spiked grass carp tissues ranged from 76.2% to 82.9% and the coeffi- cients of variation varied between 1.8% and 7.5%. The stable and efficient monoclonal cell line obtained is a sustainable source of sensitive and specific antibody to MG and LMG.