A NEW SIMPLE AND RAPID HPLC METHOD FOR DETERMINATION OF DEHP IN PVC PACKAGING AND RELEASING STUDIES

A new simple, rapid and sensitive reverse-phase liquid chromatographic technique for the determination of di-2-ethylhexyl phthalate (DEHP), the major plasticizer of most PVC materials, is proposed. The proposed method is characterised by a single liquid/liquid hexane extraction procedure which can be used either for direct DEHP determination in PVC raw material or for the analysis of leached DEHP in the infusion bags during the perfusion process. The detection of DEHP is performed based on UV absorbance at 270 nm after direct injection of the hexane extract in a miscible eluent consisting of an acetonitrile/methanol mixture (9:1, v:v). The chromatographic process takes place on a classical C-18 stationary phase. Linearity of the method is assumed from 0.25 to 5 ppm of DEHP with an acceptable repeatibility and reproducibility (RSD lower than 1.5 and 2.5%, respectively). Trace analysis is shown to be possible with respect to the limit of detection of 0.05 ppm. Moreover, the interesting possibility of using a reduced internal diameter column (2.1 mm) is underlined with respect to the resulting increase in sensitivity (0.01 ppm detectable). Some practical pharmaceutical applications are presented in order to demonstrate the reliability of the proposed method for the determination of DEHP in PVC packaging, as well as for traces of DEHP leached in infusion bags.