Identification of unknown plasticizers in polyvinyl chloride toys

Abstract

In our previous study, three unknown plasticizers were detected in five polyvinyl chloride (PVC) toys on the Japanese market. In this study, we isolated these three plasticizers (1–3), and their structures were determined using accurate mass and nuclear magnetic resonance (NMR) spectral data. One of the plasticizers was identified as bis(2-propylheptyl) phthalate (DPHP). The others were assumed to be (4-methyl-2-propylhexyl)(2-propylheptyl) phthalate and bis(4-methyl-2-propylhexyl) phthalate. This is the first study to detect these phthalic acid esters in PVC toys in Japan. Isolated DPHP was subjected to quantitative NMR (qNMR). Using the NMR solution with the absolute concentration as a calibrant, the DPHP concentration in five PVC toys was then determined by GC/MS. The amount of DPHP ranged from 14.5–21.9wt%, whereas the DPHP level in one of the PVC toys was below the quantification limit (0.05wt%).