Phthalates Impurity Analysis of PVC Resin Made with Alternative Plasticizers
Product: JMS-Q1500GC GC/MS System
Introduction
The phthalates used as plasticizers in polymer resins are endocrine-disrupting substances that are a risk to human health. Therefore, the use of phthalates is limited by various government agencies. In the field of electrical equipment manufacturing, diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), and di-2-ethylhexyl phthalate (DEHP) are regulated by the European Union’s Restriction of Hazardous Substances (RoHS) Directive. The use of DBP, BBP, DEHP, di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP) in toys and baby care products is regulated in Europe, the United States, China, and Japan. Phthalates subject to regulation are being replaced with alternative substances. However, it is known that phthalates tend to contaminate the manufacturing process and storage areas. Some alternative materials (e.g., tris-2-ethylhexyl trimellitate [TOTM]) may contain regulated components (e.g., DEHP) as impurities. In this report, PVC cables for commercial products using alternative substances as plasticizers were analyzed by the pyrolysis/thermal desorption–gas chromatography–mass spectrometry (Py/TD-GC-MS) method described in IEC 62321-8: 2017 [1]. Any phthalates discovered were quantified, and spectral information was collected for other detected compounds.
Experiment
About 0.5 mg sample of PVC electrical conduit without metal conducting wire was measured by Py/TD-GC-MS. NIMJ CRM 8152-a is a PVC pellet containing about 1000 ppm of DIBP, DBP, BBP, DEHP, and DNOP, and is certified as a standard substance manufactured by the National Institute of Advanced Industrial Science and Technology. The standard sample was dissolved in tetrahydrofuran (THF) and adjusted to a concentration of 50 mg/mL. Next, 10 μL of THF solution was dispensed into a sample cup using a micropipette, and 5 μL of n-hexane solution containing 0.1 mg/mL of DINP and DIDP was added. The measurement conditions of the sample and the standard sample are shown in Table 1.