Using an optimized relative response factor database to simplify a pyrolyzer/thermal desorption-gas chromatography-mass spectrometry method of screening for phthalate esters, polybrominated diphenyl ethers, and polybrominated biphenyls in polymers

Abstract

The international analytical standard IEC 62321–3–3 describes a method for the screening analysis of phthalate esters, polybrominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) in polymers by pyrolyzer/thermal desorption-gas chromatography-mass spectrometry (Py/TD-GC/MS). The IEC 62321–3–3 method uses a database of relative response factors (RRFs) (calculated by dividing the response factor (RF) for a target compound by the RF value for a substitute compound (SC) selected from among all target compounds) to quantitate each targeted analyte. A drawback of this method is that a separate RRF database must be created from expensive standard solutions that contain each targeted compound for each instrument, which is a labor-intensive task. In this study, we have developed a “ready-to-use” RRF database that can be used on multiple different instruments. This method eliminates the need to create an RRF database for each instrument and greatly simplifies the screening workflow described in the IEC 62321–3–3 standard. Because it only requires a mixed n-alkane solution and polymer reference materials, which are generally easy to procure and easy to use, the method is highly convenient and suitable for general-purpose use. Assigning tetra-BDE, penta-BDE, deca-BDE, or deca-BB as the SC for each PBDE and PBB analyte allowed the variance in RRFs between instruments to be reduced to a degree suitable for screening analysis. When this method was applied, recovery rates of individual PBDEs and PBBs remained within the range of 74–130 % over an extended period of 54 months. Simultaneous analysis of phthalate esters, PBDEs, and PBBs in various polymer reference materials was also performed with the optimized method on four different instruments and recovery rates of each targeted compound were evaluated. The recovery rates for each phthalate ester, total PBDEs, and total PBBs were within the range of around 100 ± 30 % for all tested samples.