Determination of styrene and styrene additives using cylindrical microelectrodes in acetone

Abstract

Cylindrical carbon fibre microelectrodes (CFMEs) (8 mm in diameter, 8 mm in length) were used to develop voltammetric methods for the determination of the antioxidant 4-tert-butylcatechol (TBC) in styrene, and of styrene in polystyrene samples. Acetone, containing 0.01 mol l⁻¹ sodium perchlorate as supporting electrolyte, was selected as a suitable working medium. A good adjustment of the voltammetric responses to that predicted by the theory was found. Reproducible electroanalytical responses were obtained with no need of applying cleaning treatments to the CFME. Using square-wave voltammetry (SWV), linear calibration graphs were obtained for TBC and styrene in the 1.0 × 10⁻⁶–1.0 × 10⁻⁴ mol l⁻¹ range, with detection limits of 4.3 × 10⁻⁷ mol l⁻¹ and 4.0 × 10⁻⁷ mol l⁻¹, respectively. The sensitivity of the method for styrene was around four orders of magnitude better than that reported for another microelectrode-based electroanalytical method. Voltammograms from mixtures of TBC and styrene showed two well-defined oxidation peaks with a difference between the peak potentials of 600 mV. Commercial styrene samples containing 0.005% of TBC were analyzed with good results. In addition, the method was applied to the determination of styrene in spiked polystyrene yoghurt packagings.