Spectroscopic quantifiication of preservatives in different food matrices using QuEChERS extraction and multivariate calibration with comparison against liquid chromatography

The application of QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction procedure has recently received significant attention, particularly for quantifying food additives in complex food matrices. A reliable analytical method based on QuEChERS extraction, UV spectroscopic measurement at 200–320 nm and partial least square regression PLS1 was outlined to determine two classes of preservatives in different processed food products. Examined additives were sodium benzoate SB, potassium sorbate PS, propylparaben PP, and methylparaben MP which showed highly overlapping UV spectra. The method indicated high detection of preservatives down to 1.1–2.4 mg/kg, recoveries between 97 and 102%, and RSD ≤ 7.0%. The efficient extraction of preservatives by QuEChERS from real matrices has improved the snentivity of spectral measurement and the detection of the analytical procedure. Methylparaben, MP, was detected in most samples with levels of 24.5, 74.3 and 393.7 mg/kg in liquid drinks, corn flakes, and soya sauce, respectively. The levels of preservatives were found to be within the regulated limits in all tested items. The outlined QuEChERS along with PLS1 calibration of spectroscopic data is proved to be a suitable alternative for liquid chromatography to monitor different types of preservatives in complex food matrices. The validity of the proposed method was checked against standard liquid chromatography.