title: Determination of malachite green and its metabolite, leucomalachite green, in catfish (Ictalurus punctatus) tissue by liquid chromatography with visible detection.
abstract: To determine residues of malachite green (MG) and its metabolite, leucomalachite green (LMG), in catfish tissue, analytes are extracted with acetonitrile-buffer and the extract is partitioned into methylene chloride. Final cleanup and isolation are performed on neutral alumina solid-phase extraction (SPE) and propylsulfonic acid cation-exchange SPE columns before analysis by liquid chromatography with visible detection. PbO2 postcolumn oxidation is performed by isocratic elution with a buffered mobile phase from a cyano column. Recoveries and relative standard deviations (RSDs) from fortified catfish tissues were 72.9% (RSD, 1.92%; 23 ppb), 75.5% (RSD, 6.85%; 11 ppb), and 69.6% (RSD, 6.93%; 5.7 ppb) for MG and 87.4% (RSD, 2.92%; 21 ppb), 88.1% (RSD, 5.94%; 10 ppb), and 82.6% (RSD, 11.5%; 5.3 ppb) for LMG. The method was applied to MG-incurred catfish at depuration times of 0, 2, 4, 8, and 24 h. Average levels of residual MG and LMG in the 24 h depuration catfish tissue were 73.4 and 289 ppb, respectively.
authors.affiliation: U.S. Food and Drug Administration, Animal Drugs Research Center, Denver Federal Center, CO 80225-0087, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Roybal
authors.forename: A P
authors.initials: AP
authors.lastname: Pfenning
authors.forename: R K
authors.initials: RK
authors.lastname: Munns
authors.forename: D C
authors.initials: DC
authors.lastname: Holland
authors.forename: J A
authors.initials: JA
authors.lastname: Hurlbut
authors.forename: A R
authors.initials: AR
authors.lastname: Long
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D007059:Ictaluridae; D012394:Rosaniline Dyes / Q000032:analysis* / Q000378:metabolism; D012680:Sensitivity and Specificity
chemical_list: D012394:Rosaniline Dyes; C005095:malachite green