Rapid method for determination of leucogentian violet in chicken fat by liquid chromatography with electrochemical detection.

The metabolite leucogentian violet (LGV) was found in chicken fat obtained from chickens dosed with gentian violet (GV); however, no residues of the parent compound, GV, and its oxidized metabolites were found. Therefore, a rapid method was developed for the specific determination of LGV in chicken fat. Chicken fat containing LGV is separated from the cellular protein with methylene chloride. LGV is then separated from the fat by partition extraction with an aqueous acid phase in which LGV is protonated, and the fat is discarded with the methylene chloride layer. The aqueous solution is neutralized, LGV is re-extracted into methylene chloride, and the methylene chloride is evaporated. An acetonitrile-water solution containing LGV is filtered before liquid chromatography using a cyano column, an acetate buffer-acetonitrile mobile phase, and an electrochemical detector set at a potential of +1.000 V. Average recoveries of LGV from chicken fat were 83.9% with a coefficient of variation (CV) of 12.9% for the 5 ppb level; 82.8% with a CV of 13.5% for the 10 ppb level; and 77.7% with a CV of 2.56% for the 20 ppb level. Levels of incurred LGV in chicken fat averaged 49.3 ppb with a CV of 2.43%.