Simultaneous Screening of 33 Restricted Substances in Polymer Materials Using Pyrolysis/Thermal Desorption Gas Chromatography–Mass Spectrometry

Abstract

The purpose of this study was to offer a quick and efficient method to screen for multiple restricted additives in polymer materials. A solvent-free pyrolysis gas chromatography–mass spectrometry method was developed to simultaneously screen 33 restricted substances, comprising 7 phthalates, 15 bromine flame retardants, 4 phosphorus flame retardants, 4 ultraviolet stabilizers, and 3 bisphenols. The pyrolysis technique and temperatures affecting additive desorption were studied. Under optimized conditions, the detection limits of the method were between 100 and 300 mg/kg. The linear range was between 100 and 1000 mg/kg in 16 compounds, and in the others it was between 300 and 1200 mg/kg. In this study, in-house reference materials, certified reference materials, and capability verification samples were used for method verification. The relative standard deviation of this method was less than 15%, and recoveries ranged from 75.9 to 107.1% for most of the compounds, with a few exceeding 120%. More importantly, the screening method was verified with 170 recycling plastic samples and original plastic samples. The experimental results showed that phthalates were the main additives in original plastics, and among 170 recycling plastics, 14 samples were found to contain restricted additives. The main additives in recycling plastics were bis(2-ethylhexyl) phthalate, di-iso-decyl phthalate, di-iso-nonyl phthalate, hexabromocyclododecane, and 2,2’,3,3’,4,4’,5,5’,6,6’-decabromodiphenyl ether. Compared with traditional methods, an important advantage is that this method tests for 33 additives, covering a variety of additives limited by laws and regulations, and therefore can provide more comprehensive and thorough inspections.

Keywords: Polymer materials, Additive, Pyrolysis gas chromatography mass spectrometry, Simultaneous screening