Determination of effect of pH and storage temperature on leaching of phthalate esters from plastic containers by ultrasound-assisted dispersive liquid-liquid micro-extraction

Phthalate esters (PEs) are consistently used plasticizers in the manufacture of plastic-based products. The over usage and dependency on PEs had made it as one of the substantial source for being classified as endocrine disrupting chemical. Drinking water (Dw) and beverages (Bv) are common food products available in plastic containers and consumed worldwide irrespective of age. During storage, these products are more prone to PE leaching from containers and continuous consumption of these may result in exceeding the minimal risk limit. In the present study, influence of pH and storage temperature (37 and 4 degrees C) on leaching of PEs from plastic container into the medium was studied by ultrasound-assisted dispersive liquid-liquid micro-extraction. Simultaneous detection of 14 PEs regulated in food products were optimised based on experimental design. Extraction solvents and operational conditions were determined to be 925 mu L chloroform, 1.6 mL ethanol and 4.4 min of ultra-sonication for Dw sample and 600 mu L chloroform, 2.0 mL ethanol and 3.0 min of ultra-sonication for Bv sample. Limit of detection and limit of quantification for PEs extracted from Dw and Bv samples were determined to be 0.1 and 0.50 mu g mL(-1). Three PEs: diethyl phthalate, dibutyl phthalate and diethylhexyl phthalate were detected in Dw and Bv samples stored at 37 and 4 degrees C. Concentration of PEs in Dw ranged from 0.004 to 1.096 mu g L-1 and in Bv sample ranged from 0.008 to 1.612 mu g mL(-1). Thus, the study would serve as surveillance to initiate awareness on food products stored in plastic containers.