Quantification of Poly(vinyl chloride) Microplastics via Pressurized Liquid Extraction and Combustion Ion Chromatography

A reliable analytical method has been developed to quantify poly(vinyl chloride) (PVC) in environmental samples. Quantification was conducted via combustion ion chromatography (C-IC). Hydrogen chloride (HCl) was quantitatively released from PVC during thermal decomposition and trapped in an absorption solution. Selectivity of the marker HCl in complex environmental samples was ensured using cleanup via pressurized liquid extraction (PLE) with methanol at 100 degrees C (discarded) and tetrahydrofuran at 185 degrees C (collected). Using this method, recoveries of 85.5 +/- 11.5% and a limit of quantification down to 8.3 mu g/g were achieved. A variety of hard and soft PVC products could be successfully analyzed via C-IC with recoveries exceeding >95%. Furthermore, no measurable overdetermination was found for various organic and inorganic matrix ingredients, such as sodium chloride, sucralose, hydroxychloroquine, diclofenac, chloramphenicol, triclosan, or polychlorinated biphenyls. In addition, sediments and suspended particular matter showed PVC concentrations ranging up to 16.0 and 220 mu g/g, respectively. However, the gap between determined polymer mass and particle masses could be significant since soft PVC products contain plasticizers up to 50 wt %. Hence, the results of the described method represent a sum of all chlorine containing polymers, which are extractable under the chosen conditions.

Automated summary

A reliable method using combustion ion chromatography (C-IC) was developed to quantify poly(vinyl chloride) (PVC) in environmental samples. The method allowed for the selective quantification of hydrogen chloride (HCl) released from PVC during thermal decomposition. Various hard and soft PVC products were successfully analyzed using this method. The results represent the sum of all chlorine-containing polymers extractable under the chosen conditions.