Determination of Contaminants in Polyolefin Recyclates by High-Performance Liquid Chromatography - Mass Spectrometry (HPLC-MS)

Plastic recycling is necessary to reduce pollution. However, the impurities in recycled plastics restrict their applications. Potential contaminants in recycled plastics were investigated by untargeted and targeted liquid chromatography-mass spectrometry (LC-MS). More than 2000 features were screened by comparing the recycled plastics with food contact polyolefin materials. A total of 126 substances was identified using the mzCloud database. In order to assess the risk of recycled plastics, Cramer rules were applied to predict the safety levels of the identified compounds. 23 identified Cramer class III compounds were assigned, including plasticizers, antioxidants, and flame retardants. Six more commonly identified toxic compounds were further characterized by standards using tandem mass spectrometry. These results suggested that the identification of contaminants in recycled plastics by LC-MS and mzCloud match was reliable. Additionally, their concentrations were determined by LC-MS to estimate the potential risk of recycled plastics. The results show that the organic additives in recycled plastics and food contact polyolefins are significantly different. Recycled plastics may present a safety risk and should be assessed before use in some applications.

Automated summary

Plastic recycling is necessary to reduce pollution, but impurities in recycled plastics restrict their applications. This study identified potential contaminants in recycled plastics using LC-MS and mzCloud matching, and assessed their safety. The results showed significant differences in organic additives between recycled plastics and food contact polyolefins, indicating a potential safety risk.