Assay of the Set of All Sudan Azodye(I,II,III,IV,and Para-Red)Contaminating Agents by Liquid Chromatography-Tandem Mass Spectrometry and Isotope Dilution Methodology

摘要

A high-throughput mass spectrometric method is presented for the simultaneous detection of Sudan I,II,III,IV,and Para-Red azodyes in foodstuff.The method is based on the use of deuterium-labeled internal standards and atmospheric pressure chemical ionization(APCI)in a triple-quadrupole instrument.The gas-phase breakdown pattern of each labeled and unlabeled analogue displays the naphthoic moiety as a common fragment.The search for the parents of this common species(parent ion scans)allows,by flow injection and in a single run,the evaluation of the presence of each polluting species spiked in typical foodstuffs.A detailed assay of each azodye was performed by LC-APCI and isotope dilution method,through the multiple reaction monitoring approach,using deuterium-labeled internal standards.Sudan dyes can be quantified above the threshold of 10 ppb except for Sudan Para-Red,for which the limit of quantification was 20 ppb,likely due to the different ionization efficiency.