GAS-CHROMATOGRAPHIC MASS-SPECTROMETRIC CONFIRMATION OF LEUCOMALACHITEGREEN IN CATFISH (ICTALURUS-PUNCTATUS) TISSUE

A gas chromatographic/mass spectrometric (GC/MS) method was developed to confirm the presence of leucomalachite green (LMG), a metabolite of the triphenylmethane dye malachite green (MG), in catfish tissue, Res idues were isolated according to a previously described liquid chromat ographic (LC)/VIS spectrometric analysis of MG and LMG in fish, In our isolation procedure, analytes are extracted from tissue with acetonit rile-buffer, partitioned into CH2Cl2, and applied to neutral alumina a nd propylsulfonic acid solid-phase extraction cartridges, Before GC/MS analysis, extracts prepared for the LC determinative method are elute d from a cyano solid-phase extraction cartridge, extracted into organi c solvent, and concentrated for GC/MS analysis, Selected ion monitorin g was performed by using 5 diagnostic ions (m/z 330, 329, 253, 210, an d 165) of LMG, The method was validated by confirming LMG in tissue fo rtified with mixtures of MG and LMG (5 and 10 ng/g each) and in tissue from fish that had been exposed to low levels of MG.