Shortening the Analysis Time of a “Ready-To-Use” Relative Response Factor Database-Coupled Pyrolyzer/Thermal Desorption–Gas Chromatography–Mass Spectrometry Method of Screening for Phthalate Esters, Polybrominated Diphenyl Ethers, and Polybrominated Biphenyls in Polymers

Abstract

The European Union RoHS Directive restricts the presence of phthalate esters, polybrominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) in electrotechnical products. The international standard IEC 62321-3-3 describes a method of screening for these chemicals using gas chromatography–mass spectrometry with a pyrolyzer/thermal desorption accessory (Py/TD-GC/MS). Although the IEC 62321-3-3 method is effective at determining levels of these restricted compounds in polymers, applying this method in RoHS testing poses two issues: it requires the preparation of a relative response factor (RRF) database from expensive standard mixed solutions, and it has a long analysis time (30 min). In a previous report, we described a method based on a “ready-to-use” RRF database that eliminates preparation of the RRF database. In this report, we resolved the remaining issue by improving the analytical throughput of the IEC 62321-3-3 method. By optimizing the Py/TD and GC/MS conditions, we almost halved the analysis time to 16 min while maintaining analytical accuracy. These optimized conditions were then combined with the above-mentioned “ready-to-use” RRF database to create a new method that resolves both of the issues with the IEC 62321-3-3 method. This new method demonstrated good sensitivity with a lower limit of detection of under 30 mg/kg for each target compound. We also assessed the analytical accuracy of this new method by analyzing various standard polymer materials on two different analytical instruments. On both instruments, the mean recovery rate was within 100 ± 30% for seven phthalate esters and for combined concentrations of PBDE and PBB congeners, which demonstrated that the quantitative accuracy of the new method is sufficient for RoHS testing. The new method resolves the issues with the IEC 62321-3-3 method and offers rapid, simple, and reliable screening that can be adopted for RoHS testing.