Determination of THMs in soft drink by solid-phase microextraction and gas chromatography

In this study, a simple and fast method was developed for the analysis of trihalomethanes (THMs) in soft drink samples using headspace solid-phase microextraction coupled with gas chromatography (HS-SPME–GC). The influence of factors, such as, extraction temperature, extraction time, addition of sodium chloride and agitation speed on extraction yield was studied through an univariate experimental design strategy. Satisfactory recoveries (⩾90%) and precision, calculated as the relative standard deviations (RSD ⩽ 11%), were obtained. The limit of detection (LOD) between 0.22 and 0.46 μg L−1 was achieved for THMs along with a wide linear range of concentrations. The applicability of the proposed method was demonstrated by analysing 74 real soft-drink samples. Since no matrix effects were observed, quantification could readily be carried out by external calibration with deionized water standards.