Determination of plastic monomers in water by solid-phase microextraction coupled with liquid chromatography

A method is presented for the determination of 2 major plastic monomers, terephthalic acid and vinyl acetate, which are widely used to manufacture plastics that come in contact with foods. The analytes are extracted from aqueous solution by using solid-phase microextraction, followed by quantitation by liquid chromatography (LC) with UV detection. Multivariate optimization was applied and is described. The optimized method has linear ranges of 5-150 mug/g for terephthalic acid and 7.5-100 mug/g for vinyl acetate. Coefficients of variation at a spiking level of 20 mug/g were 13.6% for terephthalic acid and 3.1% for vinyl acetate; detection and quantitation limits were 0.59 and 1.99 mug/g, respectively, for terephthalic acid and 1.56 and 5.20 mug/g, respectively, for vinyl acetate. The characteristics of both the extraction technique and its coupling with LC are described and discussed.