Solvent extraction of UV stabilizers in plastics: A step towards methodology harmonization

The environmental pollution caused by plastics and their chemical additives has drawn global attention. UV stabilizers are among the major plastic additives that were used to protect against discoloration and degradation under sunlight. They are recognized as harmful due to its persistence, bioaccumulation, adverse effects, and potential for long-range environmental transport via plastics. However, non-harmonized methodology to analysis UV stabilizers in plastics has brought remarkable challenge to compile data across studies and conduct further risk assessment. Especially, the extraction solvent was diverse, whereas their extract efficiency was unknown. To address this knowledge gap, this study assessed the extraction efficiency of three commonly used organic solvents (dichloromethane (DCM), methanol (MeOH) and toluene (PhMe)) for UV stabilizers in different type of plastics, including foil-based polymer (Polyethylene, Polypropylene, Polystyrene, and Polyethylene terephthalate), bio-based plastics (Polylactic acid) and tire rubber. A total of 8 UV stabilizers were detected with a concentration range between 0.01 and 257.94 μg/g. OC had the highest detection rate (100%) and concentration (0.21–257.94 μg/g). The extraction performance of the three extractants was further evaluated, and it was found that not only the extraction performance but also the stability, DCM performed significantly better than MeOH and PhMe.