title: Quantitative and confirmatory analyses of malachite green and leucomalachite green residues in fish and shrimp.
abstract: Liquid chromatographic methods are presented for the quantitative and confirmatory determination of malachite green (MG) and leucomalachite green (LMG) for channel catfish, rainbow trout, tilapia, basa, Atlantic salmon, and tiger shrimp. Residues were extracted from tissues with ammonium acetate buffer and acetonitrile and isolated by partitioning into dichloromethane. LMG was quantitatively oxidized to the chromic MG with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Extracts were analyzed for total MG by liquid chromatography with both visible detection (LC-VIS) at 618 nm for routine screening and ion trap mass spectrometry (LC-MSn) with no discharge-atmospheric pressure chemical ionization for residue confirmation. The method was validated in each species fortified with LMG at 1, 2, 4, and 10 ng/g (ppb), and average recoveries ranged from 85.9 to 93.9%. Quantitative data were consistent for the two detection methods, with measured method detection limits of 1.0 ng/g for LC-VIS and 0.25 ng/g for LC-MSn. Incurred tissues from catfish, trout, tilapia, and salmon that had been treated with MG were also extracted and analyzed as part of this study.
authors.affiliation: Animal Drugs Research Center, Food and Drug Administration, Denver Federal Center, P.O. Box 25087, Denver, Colorado 80225-0087, USA.
authors.forename: Wendy C
authors.initials: WC
authors.lastname: Andersen
authors.forename: Sherri B
authors.initials: SB
authors.lastname: Turnipseed
authors.forename: José E
authors.initials: JE
authors.lastname: Roybal
mesh_terms: D000814:Aniline Compounds / Q000032:analysis*; D000818:Animals; D017756:Aquaculture; D002853:Chromatography, Liquid / Q000379:methods; D005399:Fishes; D005506:Food Contamination / Q000032:analysis*; D007059:Ictaluridae; D017686:Oncorhynchus mykiss; D033561:Penaeidae; D012394:Rosaniline Dyes / Q000032:analysis*; D020317:Salmo salar; D017210:Tilapia
chemical_list: D000814:Aniline Compounds; D012394:Rosaniline Dyes; C005095:malachite green; C015320:leucomalachite green