Fast voltammetric assay of water soluble phthalates in bottled and coolers water

Abstract

Detection of phthalic acid and phthalates esters is of growing interest due to their significant use and potential toxicity. A fast, simple and highly sensitive Square Wave Voltammetric (SWV) method developed for determination of total water soluble phthalates using a glassy carbon electrode (GCE) is demonstrated using di-n-butyl phthalate (95%) (DBP) as a test example. The study showed that 100 μmol L⁻¹ aqueous solution of DBP gives the best response with 0.05 mol L⁻¹ tetrabutylammonium bromide (TBAB), at stirring rate of 1400 rpm, deposition time, 20 s and pH 4.0 ± 0.1. The optimum frequency and scan rate was 100 Hz and 0.9 V s⁻¹ respectively. Voltammetric response was linear over 3 ranges, 70–110 μmol L⁻¹, 20–60 μmol L⁻¹ and 2–10 μmol L⁻¹ with regression coefficient of 0.9873, 0.9978 and 0.9935 respectively and limit of detection (LOD), 0.47 μmol L⁻¹ for total water soluble phthalates in aqueous medium. The method was successfully applied to the determination of total phthalates in water samples taken from sources of water stored in PVC coolers and plastic bottles.