Development of a method for the analysis of seven banned azo-dyes in chilli and hot chilli food samples by pressurised liquid extraction and liquid chromatography with electrospray ionization-tandem mass spectrometry

An automated, confirmatory and sensitive procedure has been developed and validated for the determination of Sudan (I–IV), Sudan Orange G, Sudan Red 7B and Para Red in hot chilli food samples. The proposed method includes pressurised liquid extraction (PLE) with acetone, gel permeation chromatography (GPC) clean-up and detection by liquid chromatography (LC) coupled to electrospray ionization in positive mode tandem mass spectrometry (ESI-MS–MS). The main parameters affecting the performance of the different ionization sources and PLE parameters were previously optimised using statistical design of experiments (DOE). The method was in-house validated on chilli powder and chilli meat. Linear calibrations were obtained with correlation coefficients R2 > 0.999. The limits of detection (LOD) and quantification (LOQ) of the method were in the ranges of 0.002–0.012 ng g−1 and 0.006–0.036 ng g−1, respectively for chilli powder. The decision limit and detection capability were between 0.005–0.022 ng g−1 and 0.007–0.026 ng g−1, respectively for chilli meat. Recoveries ranged from 94% to 105%. The applicability of the method to the determination of azo-dyes in hot chilli products was demonstrated.