Simultaneous Determination of Four Sudan Dyes in Egg Yolks by Molecularly Imprinted SPE Coupled with LC-UV Detection

Chromatographia (Impact Factor: 1.44). 73(3):227-233. DOI: 10.1007/s10337-010-1872-7

ABSTRACT A highly selective molecularly imprinted solid-phase extraction (MISPE) combined with liquid chromatography-ultraviolet detection
was developed for the simultaneous isolation and determination of four Sudan dyes (I, II, III and IV) in egg-yolk products.
The imprinted microspheres synthesized by suspension polymerization using phenylamine–naphthol as mimic template show high
selectivity and affinity to the four kinds of Sudan dyes and were successfully applied as selective sorbents of solid-phase
extraction for the simultaneous determination of the four Sudans from egg-yolk samples. Good linearity was obtained in a range
of 0.062–10μgg−1 and the average recoveries of the four Sudans at three spiked levels ranged from 94.1 to 102.5% with the relative standard
deviations less than 5.8%. The developed extraction protocol eliminated the effect of template leakage on quantitative analysis
and could be applied for the determination of Sudans in complicated food samples.

KeywordsColumn liquid chromatography–Molecularly imprinted solid-phase extraction–Imprinted microspheres–Sudan dyes–Egg yolk

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    ABSTRACT: A multiresidue method for simultaneous determination of 10 dyes unauthorised for the use in laying hens was developed (Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red G, Sudan Orange G, Sudan Red 7B, Para-Red, Toluidine Red, Citrus Red). The dyes were extracted using liquid-liquid extraction with acetonitrile in the presence of anhydrous sodium sulphate, and cleaned using zirconium coated silica cartridges. After dilution with acetonitrile saturated with hexane:DMSO (8:2), samples were analysed using LC-MS/MS system with acetonitrile (A) and 0.1% formic acid (B) as a mobile phase in a gradient mode and C 18 analytical column. The method was validated according to the requirements described in the Commission Decision 2002/657/EC: linearity (r ≥ 0.998), precision: repeatability (1.94%–10.02%), and within-laboratory reproducibility (4.66%–8.89%), recovery (97%-105%), decision limit CCα (5.33-6.50 µg/kg), and detection capability CCβ (6.18-7.50 µg/kg) were calculated. The developed method fulfilled all performance criteria and can be used in the official survey of dyes residues in food of animal origin.