Development of a screening method for phthalate esters in polymers using a quantitative database in combination with pyrolyzer/thermal desorption gas chromatography mass spectrometry.

Seven phthalate esters (di-isobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), di-isononyl phthalate (DINP) and di-isodecyl phthalate (DIDP)) were analyzed by pyrolyzer/thermal desorption-gas chromatography/mass spectrometry (Py/TD-GC/MS), the retention index and relative response factor (RRF) relative to DEHP was calculated for each compound and used to construct a quantitative database (qDB). This qDB enables normalization of the retention time and response factor of each phthalate ester between any laboratory simply by analyzing an n-alkane solution and DEHP standard material. This allows for easy calculation of the phthalate ester content of samples without preparation of calibration curves. The efficacy of this qDB method was verified by performing a quantitative analysis of phthalate esters at 4 different laboratories that showed actual retention times were within ±0.012 min of the estimated retention times for all compounds at all laboratories. Similarly, the mean recovery rate (n = 6) at each laboratory was within 79-113%. Quantitative analysis was also performed on 30 real samples using both the qDB method and the Py/TD-GC/MS method set forth in IEC62321-8, which involves the preparation of 1-point calibrations to perform quantitative analysis. The difference in quantitative results between the methods was approximately within ±200 mg/kg for compounds in the concentration region of <2000 mg/kg.

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