Development of a liquid chromatography–tandem mass spectrometry with ultrasound-assisted extraction method for the simultaneous determination of sudan dyes and their metabolites in the edible tissues and eggs of food-producing animals

• A new LC–MS/MS method to determine 6 sudan dyes and their metabolites in 12 kinds of animal derived food.
• Ultrasound-assisted extraction speeds up the sample extraction procedure and decrease the volume of extract solvent.
• Fast and simple approach with low LODs, good linearity and repeatability.

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed for the simultaneous determination of sudan I, sudan II, sudan III, sudan IV, and their metabolites such as 4-aminoazobenzene and ortho-aminoazotoluole in 12 animal derived foods (including the muscle and liver of swine, muscle, liver and skin of chicken and duck, muscle and skin of fish, as well as the eggs of hen and duck). Sample preparation procedure included ultrasound-assisted extraction with acetonitrile, defatting with n-hexane and final clean-up with solid phase extraction (SPE) on Aluminum B cartridges. The detection and quantification of the 6 sudan dyes and their metabolites were performed by a reversed-phase liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry (LC/ESI-MS/MS). The CCαs and the CCβs of various samples varied from 0.03 μg/kg to 0.12 μg/kg, 0.09 μg/kg to 0.19 μg/kg, respectively. The recoveries of spiked sample from 0.2 μg/kg to 0.8 μg/kg ranged from 61.9% to 87.4% with the relative standard deviations of less than 19.1%. Performances of the whole analytical procedure meet the criteria established by the European Commission for mass spectrometric detection.