LC-MS/MS Analysis of Malachite Green, Leucomalachite Green, Ciprofloxacin, and Tetracycline in Food Samples using a TurboFlow Method

Accurate monitoring of chemical residue levels in food and agriculture products is essential to assure food supply safety and manage global health risks. Analysing chemical residues requires techniques sensitive enough to detect and quantify contaminants at or below the maximum residue limit (MRL) of the compound in a given sample matrix. In addition, because of increased food safety regulations and the growing numbers of samples to be analysed, it is critical that the analytical techniques provide high sample throughput. With the continuing rapid growth of the aquaculture industry, there is increasing concern about the use of unapproved drugs and unsafe chemicals in aquafarming operations. Malachite green (MG), a triphenylmethane dye, is an effective and inexpensive fungicide used in aquaculture, particularly in Asian countries (Figure 1). During metabolism, malachite green reduces to leucomalachite green (LMG), which has been shown to accumulate in fatty fish tissues and can be found long after MG may no longer be detected [1]. Both MG and LMG have demonstrated putative carcinogenic activity, and thus MG has been banned for use as an aquaculture veterinary drug in many countries including the United States and Canada as well as the European Union (EU). For substances banned from use in food producing animals, EU legislation defines minimum required performance limits. For malachite green, an analytical test method must be able to determine the sum of MG and LMG residues in fish muscle at the minimum required performance limit of 2 μg/kg (ppb) [2].