Determination of malachite green residues in fish using molecularly imprinted solid-phase extraction followed by liquid chromatography–linear ion trap mass spectrometry

• Published in: Analytica chimica acta 2010-04, Vol.665 (1), p.47-54
• Main Authors: Martínez Bueno, María Jesús, Herrera, Sonia, Uclés, Ana, Agüera, Ana, Hernando, María Dolores, Shimelis, Olga, Rudolfsson, Marcus, Fernández-Alba, Amadeo R.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Animals; Binding; Brilliant green; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Chromatography, High Pressure Liquid - methods; Crystal violet; Exact sciences and technology; Extraction; Fish; Gentian Violet - analysis; Gentian Violet - isolation & purification; Imprinted polymers; Leuco-metabolites; Liquid chromatography mass spectrometry (LC–MS); Liquids; Malachite green; Mass spectrometry; Mathematical analysis; Molecular Imprinting; Molecularly imprinted polymers (MIPs); Other chromatographic methods; Quaternary Ammonium Compounds - analysis; Quaternary Ammonium Compounds - isolation & purification; Rosaniline Dyes - analysis; Rosaniline Dyes - isolation & purification; Salmon; Salmon - metabolism; Solid Phase Extraction; Spectrometric and optical methods; Spectrometry, Mass, Electrospray Ionization - methods
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2010.03.001

This paper describes the development of an analytical procedure to determine malachite green (MG) residues in salmon samples using molecularly imprinted polymers (MIPs) as the extraction and clean-up material, followed by liquid chromatography–linear ion trap mass spectrometry (LC–QqQLIT-MS/MS). MG and two structurally related compounds, crystal violet (CV) and brilliant green (BG) were employed for the selectivity test. The imprinted polymers exhibited high binding affinity for MG, while CV and BG showed less binding capacity: 47% and 34%, respectively. The recovery values of MG in salmon samples fortified with leucomalachite green (LMG) were determined by measuring the amount of MG in the sample, after carrying out the oxidation reaction with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), which converts the LMG back into chromic-form. The average recovery of MG in spiked salmon muscle over the concentration range 1–100 ng g −1 was 98% with a relative standard deviation value (R.S.D.) below 12%. The method detection limits (MDLs) obtained for MG, CV, BG and their leuco-metabolites were in the range of 3–20 ng kg −1 (ppt).