Prescreening of Phthalic Esters Contained in PVC Products by FTIR

Introduction

Phthalic esters are used as plasticizers for polyvinyl chloride (PVC) and other plastic products, but are a suspected cause of endocrine disruption in the human body. In the revised RoHS Directive (RoHS2.0), the four types of phthalic esters shown in Fig. 1 were added to the list of regulated substances, in addition to the original RoHS 6 substances (lead, mercury, cadmium, hexavalent chromium, PBB, PBDE). Under RoHS2.0, the maximum allowable contents of these four phthalic esters in all electrical and electronic devices except medical equipment and monitoring/control devices is 0.1% (1,000 ppm). Therefore, gas chromatograph-mass spectrometer (GC-MS) is generally used in analyses to determine compliance with the RoHS Directive. However, soft PVCs and certain other products include materials with high concentrations of phthalic esters, which may place an excessive load on the column used in GC-MS analyses of those materials. Because the Fourier transform infrared spectrophotometer (FTIR) does not require pretreatment and enables spectrum measurement in a short time of about 1 min, it is suitable for prescreening of phthalic esters in samples. If samples with high concentrations of phthalic esters can be prescreened in advance by FTIR, carryover of high-concentration analytes to subsequent analyses in the GC-MS analysis process can be reduced, resulting in more efficient analysis. This article introduces a prescreening analysis technique for phthalic esters in PVC products using FTIR for efficient GC-MS analysis.

November 1, 2019 GMT