title: Multi-dye residue analysis of triarylmethane, xanthene, phenothiazine and phenoxazine dyes in fish tissues by ultra-performance liquid chromatography-tandem mass spectrometry.
abstract: Beside the possible illegal use of malachite green in aquaculture, other familiar dyes could also been applied by fraudulent producers due to their antiseptic and antibacterial activity. In this contribution, a new sensitive multi-residue method was developed to determine triarylmethane, xanthene, phenothiazine and phenoxazine dyes in fish by ultra-performance liquid chromatography-tandem mass spectrometry. Samples were extracted with acetonitrile, followed by an oxidation step using 2,3-dichloro-5,6-dicyanobenzoquinone. Further clean-up was performed by tandem solid phase extraction using weak and strong cation exchange cartridges. Extracts were analysed by UPLC-MS(n) operating in the positive electrospray ionisation mode (ESI+). The fourteen dyes were separated within only 12min on a C18 BEH column using 1mM ammonium acetate in water at pH 4.5 and acetonitrile as mobile phases at a flowrate of 0.4mLmin(-1). The presented method was validated as defined by the European Union and scientific literature. Good linearity (R ≥0.99 and goodness-of-fit (g) ≤10%) was achieved over the tested concentration range (0.25-2ngg(-1)). Limit of quantification was 0.25ngg(-1) for all dyes, with a signal-to-noise ratio of at least 10/1. This is at least 5 to 10 times lower than previous published methods. Limits of detection were all <0.1ngg(-1). Precision and trueness fell within the criteria requested by the EC requirements for this concentration range. Decision limit (CCα) and detection capability (CCβ) were all <1 and <0.25ngg(-1), respectively. Due to background levels of the xanthene dyes, the two rhodamine dyes could only be determined above 0.75ngg(-1). For these dyes, the method can only be used for screening purposes. To show the applicability of the method, a monitoring study was performed to investigate the occurrence of artificial dyes in wildlife European eel in Flemish rivers.
authors.affiliation: Scientific Institute of Public Health, Food, Medicines and Consumer Safety, Chemical Residues and Contaminants, Juliette Wytsmanstraat 14, 1050 Brussel, Belgium. Electronic address: Tim.Reyns@wiv-isp.be.
authors.forename: Tim
authors.initials: T
authors.lastname: Reyns
authors.affiliation: Research Institute for Nature and Forest, Duboislaan 14, 1560 Groenendaal-Hoeilaart, Belgium.
authors.forename: Claude
authors.initials: C
authors.lastname: Belpaire
authors.affiliation: Research Institute for Nature and Forest, Gaverstraat 4, 9500 Geraardsbergen, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Geeraerts
authors.affiliation: Scientific Institute of Public Health, Food, Medicines and Consumer Safety, Chemical Residues and Contaminants, Juliette Wytsmanstraat 14, 1050 Brussel, Belgium.
authors.forename: Joris
authors.initials: J
authors.lastname: Van Loco
mesh_terms: D000818:Animals; D017756:Aquaculture; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004396:Coloring Agents / Q000032:analysis*; D004350:Drug Residues / Q000032:analysis*; D004524:Eels; D005399:Fishes; D009132:Muscles / Q000737:chemistry; D009930:Organic Chemicals / Q000032:analysis; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D004396:Coloring Agents; D009930:Organic Chemicals
keywords: Aquaculture products; Crystal violet; Dyes; Malachite green; Residue analysis; Ultra performance liquid chromatography–tandem mass spectrometry