Determination of 30 Forbidden Industrial Dyes in Processed Food by UHPLC-Orbitrap Mass Spectrometry

UHPLC-electrostatic quadrupole/orbitrap mass spectrometry was applied to the determination of 30 forbidden industrial dyes in processed food. The sample was extracted with acetonitrile-acetone-aqueous ammonia (66+33+1) mixture, and the extract obtained was purified on HLB and neutral alumina solid-phase extraction column. The purified extract was separated by HPLC using Thermo Gold C18 column as stationary phase, and mixtures of acetonitrile and 0.1% (φ) formic acid solution in various ratios as mobile phase in gradient elution. Electrospray ionization positive ion source and the mode of Target Selected Ion Monitoring-Data Dependent MS2 scanning (Target SIM-dd MS2) were adopted in the mass spectrometry. Detection limits for the 30 forbidden industrial dyes were in the range of 0.001 0-0.051 mg·kg-1. Recovery was tested by standard addition method, giving results in the range of 85.2%-96.5%, with RSDs (n=6) ranged from 2.1% to 9.8%. The mass relative deviation was within ±5×10-6.