Microchemical Journal | 2019
Effective preconcentration of volatile organic compounds from aqueous solutions with polydimethylsiloxane-coated filter paper
Abstract
Abstract This study explored a click method of using filter paper (FP) and a polydimethylsiloxane (PDMS) polymer coating solution to prepare a cost-effective volatile organic compound (VOC) preconcentrating sampler. This is the first report of successfully cross-linking a hydrophobic polymer with cellulose in filter paper via a sol-gel method and its application to the preconcentration of headspace VOCs. Our Fourier transform infrared spectroscopy analysis results of the PDMS-coated filter paper (FP-PDMS) showed that the spectral intensity of the alcoholic O H stretch from FP or PDMS was reduced by the addition of trifluoroacetic acid to the PDMS solution, which indicated that an alcohol group in PDMS underwent cross-linking with another alcohol group in the cellulose or PDMS. Scanning electron microscopy (SEM) images of FP-PDMS revealed that the fibrous structure of the FP surface was partially compromised by the PDMS coating, but the porous structure of FP is partially preserved. The addition of the PDMS coating to the FP increased the efficiency of the preconcentration of headspace VOCs evaporated from water. Three types of carbon additives, activated carbon, graphite, and fullerene, were tested in order to evaluate their effects on headspace VOC preconcentration efficiency for FP-PDMS, with the addition of activated carbon found to provide the largest increase in preconcentration efficiency. The extent of the enhancement of the preconcentration efficiency provided by the carbon additives varied with the VOC compounds, as well the type of carbon additive. The FP-PDMS both with and without activated carbon can be used to successfully preconcentrate benzene, toluene, ethylbenzene, and m-xylene from sub-ppb water samples with the headspace gas sampling method.