Determination of Phthalates in Beverages by Headspace SPME-GC Using Calix[6]arene Fiber

A headspace solid-phase microextraction, in conjunction with gas chromatography using a novel sol-gel calix[6]arene-contained fiber for the determination of phthalate acid esters in non-alcoholic beverages is described for the first time. A Taguchi's L-25 (5(6)) orthogonal array experimental design was introduced to optimize the extraction parameters such as extraction temperature, extraction time, salt concentration and stirring speed. Under the optimized conditions, the method showed linear response of three to five orders of magnitude with correlation coefficients (r) better than 0.995. Owing to the good selectivity and high sensitivity of this fiber to phthalate acid esters, the extraction was carried out in real beverage matrix and low detection limits of 0.015-0.298 mu g L-1 were achieved. The recoveries of standard addition tests amounted to 87.9-108.3% and the relative standard deviation values varied from 9.62 to 15.2%. The method was applied to the analysis of 12 kinds of beverages and bis-2-ethylhexyl phthalate was the sole analyte detected in these samples.