Abstract: A method has been developed to determine 55 plastic additives including antioxidants, plasticizers, ultraviolet light absorbers in yogurt by solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS). Samples were extracted with acetonitrile and the extract was then cleaned up on an HLB SPE column. The UPLC system equipped with a ACQUITY UPLC BEH C18 analytical column (2.1 mm × 50 mm, 1.7 μm) was operated utilizing methanol-0.1% formic acid as the mobile phase in gradient elution mode. Electrospray ionization in positive ion mode (ESI+) with multiple reaction monitoring (MRM) was used, and the analytes were quantified by the external standard method. The calibration curves displayed good linearity in a wide concentration range with a correlation coefficient of over 0.97. The average recoveries from spiked yogurt at three concentrations ranged from 62.4% to 93.5% with relative standard deviations (RSD) varying from 2.4% to 13.4%. The limits of detection (LOD) were 0.2–40 μg/kg. Twenty-three plastic additives at concentrations from 7.0 to 39 μg/kg were detected in 20 samples by the proposed method. This method can simultaneously identify and quantify a wide variety of plastic additive compounds with distinctive physicochemical properties in yogurt with high sensitivity.

Key words: plastic additives, ultra performance liquid chromatography-tandem mass spectrometry, high throughput detection, yogurt