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Expansion of the Scope of AOAC First Action Method 2012.25—Single-Laboratory Validation of Triphenylmethane Dye and Leuco Metabolite Analysis in Shrimp, Tilapia, Catfish, and Salmon by LC-MS/MS

Wendy C. Andersen, Christine R. Casey, Marilyn J. Schneider, Sherri B. Turnipseed
Journal of AOAC International 2015 v.98 no.3 pp. 636-648
analytical methods, catfish, detection limit, food contamination, gentian violet, malachite green, metabolites, salmon, seafoods, shrimp, tilapia (common name)
Prior to conducting a collaborative study of AOAC First Action 2012.25 LC-MS/MS analytical method for the determination of residues of three triphenylmethane dyes (malachite green, crystal violet, and brilliant green) and their metabolites (leucomalachite green and leucocrystal violet) in seafood, a single-laboratory validation of method 2012.25 was performed to expand the scope of the method to other seafood matrixes including salmon, catfish, tilapia, and shrimp. The validation included the analysis of fortified and incurred residues over multiple weeks to assess analyte stability in matrix at –80 °C, a comparison of calibration methods over the range 0.25 to 4 ug/kg, study of matrix effects for analyte quantification, and qualitative identification of targeted analytes. Method accuracy ranged from 88 to 112% with 13% RSD or less for samples fortified at 0.5, 1.0, and 2.0 ug/kg. Analyte identification and determination limits were determined by procedures recommended both by the U.S. Food and Drug Administration and the European Commission. Method detection limits and decision limits ranged from 0.05 to 0.24 ug/kg and 0.08 to 0.54 ug/kg, respectively. AOAC First Action Method 2012.25 with an extracted matrix calibration curve and internal standard correction is suitable for the determination of triphenylmethane dyes and leuco metabolites in salmon, catfish, tilapia, and shrimp by LC-MS/MS at a residue determination level of 0.5 ug/kg or below.