Separation and analysis of low molecular weight plasticizers in poly(vinyl chloride) tubes

The separation of plasticizers in polyvinyl chloride (PVC) tubes used in medical applications was carried out in different solvents and compared by studying the remaining PVC after separation using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), as well as by studying the extracted low molecular weight plasticizers by gas chromatography/mass spectroscopy (GC/MS) and GC. It was found that the simple room temperature extraction in chloroform showed the best separation of plasticizers from the PVC matrix. Close results on extracted diisooctyl phthalate (DOP) concentration were obtained from different methods. Analysis on one kind of the used tubes showed that 64-67% of DOP migrated to the patient, but bis(2-ethylhexyl) adipate (DOA) was 70-100% retained.