Analysis of additives in dairy products by liquid chromatography coupled to quadrupole-orbitrap mass spectrometry

Abstract

A new method combining QuEChERS with ultrahigh-performance liquid chromatography and electrospray ionization quadrupole Orbitrap high-resolution mass spectrometry (UHPLC/ESI Q-Orbitrap) was developed for the highly accurate and sensitive screening of 43 antioxidants, preservatives and synthetic sweeteners in dairy products. Response surface methodology was employed to optimize a quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation method for the determination of 42 different analytes in dairy products for the first time. After optimization, the maximum predicted recovery was 99.33% rate for aspartame under the optimized conditions of 10mL acetionitrile, 1.52g sodium acetate, 410mg PSA and 404mgC18. For the matrices studied, the recovery rates of the other 42 compounds ranged from 89.4% to 108.2%, with coefficient of variation <6.4%. UHPLC/ESI Q-Orbitrap Mass full scan mode acquired full MS data was used to identify and quantify additives, and data-dependent scan mode obtained fragment ion spectra for confirmation. The mass accuracy typically obtained is routinely better than 1.5ppm, and only need to calibrate once a week. The 43 compounds behave dynamic in the range 0.001–1000μgkg−1 concentration, with correlation coefficient >0.999. The limits of detection for the analytes are in the range 0.0001–3.6μgkg−1. This method has been successfully applied on screening of antioxidants, preservatives and synthetic sweeteners in commercial dairy product samples, and it is very useful for fast screening of different food additives.