Effect of pressure, temperature and time on supercritical fluid extraction of citrate and benzoate plasticisers from poly (vinyl chloride)

Supercritical Fluid Extraction (SFE) has been demonstrated as a useful tool in the analysis of polymeric materials. This paper describes the off-line SFE followed by Gas Chromatography determination of some citrate and benzoate plasticisers used in poly (vinyl chloride) (PVC). Experimental factors affecting SFE with carbon dioxide have been studied by gravimetric analysis. Recoveries of analytes were calculated with the use of a Gas Chromatograph with a flame ionisation detector. The extraction process can be kinetically controlled by the solubility of plasticisers in the supercritical fluid or by their diffusion through the polymer depending on pressure and temperature conditions. Quantitative extractions (>99%) are obtained at 39.5 MPa, 100 °C and 20 min, while some losses in the collection of plasticisers in a liquid solvent (ranges from 85 to 95%) are observed.