ARS | Publication request: Fluorescence screening of leucomalachite green and leucogentian violet residues in catfish

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2009
Publication Date: August 18, 2009
Citation: Chen, G., Shui, M. 2009. Fluorescence screening of leucomalachite green and leucogentian violet residues in catfish [Abstract].American Chemical Society.

Technical Abstract: The tripheylmethane dyes malachite green (MG) and gentian violet (GV) are effective fungicides, ectoparasiticides and disinfectants in aquaculture. This practice may leave toxic residues in seafood which is not allowed by FDA and many regulatory agencies worldwide. In this work, residues of their metabolites, leucomalachite green (LMG) and leucogentian violet (LGV), in catfish were screened by a fluorometric method. After extraction and cleanup with Oasis MCX columns, the analyte solution is excited at 265-nm and fluorescence is measured at 350-380 nm. LMG and LGV are oxidized next by lead dioxide to non-fluorescent MG and GV, and fluorescence is measured again. This background subtraction scheme effectively enhances assay sensitivity in food matrixes to meet the 1 ng/g FDA detection limit. The experimental procedures and applications will be discussed in detail in this presentation.