[Determination of Sudan Red dyes in eggs using liquid chromatography-tandem mass spectrometry and matrix solid-phase dispersion technique]

Abstract

A new method was established for determining Sudan Red I - IV dyes in eggs using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The target analytes in eggs such as hen eggs, duck eggs and preserved eggs, were extracted by solid-phase dispersion technique with a mixture of chloroform-acetonitrile (9: 1, v/v). The chromatographic separation was achieved on a ZORBAX SB-C18 column. The identification and quantification were performed using MS/MS with multiple-reaction monitoring (MRM) and electrospray ionizatio in positive mode. The linearity ranges of Sudan Red I - IV dyes were 0.5 - 100 ng/g, 5.0 - 100 ng/g, 1.0 - 100 ng/g and 2.0 - 100 ng/g, respectively, and all linear correlation coefficient were higher than 0.99. The recoveries of Sudan Red dyes in eggs were between 87.3% and 113% with the relative standard deviations less than 9.1%. The detection limits of this method were 0.1 microg/kg for Sudan Red I, 2.0 microg/kg for Sudan Red II , 0.2 microg/kg for Sudan Red III and 0.4 microg/kg for Sudan Red IV, which could meet the monitoring requirements of the Suda Red dyes both abroad and home.