Permeation sampling of phthalate esters in water

A method for sampling the six phthalate esters considered priority pollutants by the United States EPA has been developed. The sampling device utilizes a silicone polycarbonate membrane (SSP-M213) through which the analytes permeate and are collected onto an adsorbent, Amberlite XAD-16. After a known period, the samplers were removed from the water and the analytes were extracted from the adsorbent using dichloromethane/hexane (50:50, v/v), with the resulting solution analyzed using gas chromatography with flame ionization detection. Time-weighted average (TWA) concentrations of the phthalates in the water were determined by creating plots of amount of analyte collected versus the product of concentration and time (ppm. hr) for each phthalate. A linear correlation between the amount of analyte collected and the product of concentration and time was seen for each phthalate. Effects of temperature, stirring rate and the presence of potential interferents on the rate of permeation were also studied. The obtained and minimal amounts of solvent are used for sample preparation and injection into the gas chromatograph.