New SPME-based method for on-site measurement of gas-phase concentration of phthalates and alternatives at the surface of PVC floorings

Abstract

Phthalates are part of the semi-volatile organic compounds. They are widely used as plasticizers in polyvinyl chloride (PVC) floorings and are ubiquitous indoor pollutants. Some of them are even classified as carcinogenic, mutagenic, reprotoxic (CMR), and as we spend more time indoors, it is necessary to develop methods to assess emission strength of indoor materials. One of the key parameters to measure this potential is the concentration at the source material surface (y0). To measure directly this parameter, an in-situ sampling method using solid-phase microextraction (SPME) into an emission cell was developed. The main challenge with this method is calibration. Firstly, based on the headspace analysis of seven floorings, four samples were identified as sources of diisobutyl phthalate (DiBP), dibutyl terephthalate (DBTP) and benzoate esters. Secondly, an atmosphere generation system using a flooring sample as source of compounds and coupled with an active sampling with Tenax tubes was developed to perform an external calibration of the SPME based-MOSEC cell method suitable for y0 measurement. Calibration curves were set up on a wide range of exposure doses extending up to 96 µg min/m3 for DiBP and 184 µg min/m3 for DBTP. Low detection limits, 0.46 µg/m3 for DiBP and 1.50 µg/m3 for DBTP were determined considering an extraction time of 15 min. The principal limitation in the sampling conditions was identified as the 288 h required to reach steady state in the emission cell before the extraction step. Finally, y0 measured at the surface of PVC floorings ranged from 2.2 to 5.5 µg/m3 for DiBP and from 6.1 to 13.5 µg/m3 for DBTP.

Keywords

• Indoor air quality
• Semi volatile organic compounds (SVOCs)
• PVC flooring
• Emission cell coupled to SPME
• Calibration method