title: Liquid chromatographic determination of malachite green and leucomalachite green (LMG) residues in salmon with in situ LMG oxidation.
abstract: A liquid chromatography (LC) method is presented for the quantitative determination of malachite green (MG) in salmon. MG and leucomalachite green (LMG) residues were extracted from salmon tissue with ammonium acetate buffer and acetonitrile, and then isolated by partitioning into dichloromethane. LMG was quantitatively oxidized to the chromic MG by reaction with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Samples were then cleaned up by solid-phase extraction with alumina and propylsulfonic acid phases. Extracts were analyzed for MG by LC with visible detection at 618 nm using isocratic elution and a C18 column. The method was validated in 35 farm-raised salmon (Salmo salar) tissues fortified at 1, 2, 4, and 10 ng/g (ppb) with an average recovery of 95.4% and a relative standard deviation of +/- 11.1%, and in 5 canned salmon (Oncorhynchus gorbuscha) samples fortified at 10 ng/g with an average recovery of 88.9 +/- 2.6%. This study also included the determination of MG and LMG residues in tissues from salmon that had been treated with MG MG was quantitatively determined at the method detection limit of 1 ng/g.
authors.affiliation: U.S. Food and Drug Administration, Animal Drugs Research Center, Denver Federal Center, P.O. Box 25087, Denver, CO 80225-0087, USA. wendy.andersen@fda.hhs.gov
authors.forename: Wendy C
authors.initials: WC
authors.lastname: Andersen
authors.forename: José E
authors.initials: JE
authors.lastname: Roybal
authors.forename: Sherri B
authors.initials: SB
authors.lastname: Turnipseed
mesh_terms: D000537:Aluminum Oxide / Q000032:analysis; D000814:Aniline Compounds / Q000032:analysis*; D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods* / Q000592:standards; D005396:Fish Products / Q000032:analysis*; D005504:Food Analysis / Q000379:methods* / Q000592:standards; D005506:Food Contamination / Q000032:analysis; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D012394:Rosaniline Dyes / Q000032:analysis*; D012474:Salmon
chemical_list: D000814:Aniline Compounds; D012394:Rosaniline Dyes; C005095:malachite green; C015320:leucomalachite green; D000537:Aluminum Oxide