Spectrophotometric determination of carbon tetrachloride based on a photoactivated colour reaction

Abstract

A simple, rapid, and practical spectrophotometric method for the determination of carbon tetrachloride at the parts per million (ppm) level is presented. The method is based on the photochemical formation of the coloured complex (maximum wavelength, λ_max= 516 nm; molar absorptivity, ε= 0.57 × 10^–2 m² mol^–1) of carbon tetrachloride (CCl₄) with diphenylamine (DPA). The proposed method has a relative standard deviation of <7%, and a Sandell sensitivity of 2.7 × 10^–3µg cm^–2. The 95% confidence limit (10 determinations) for 500 ppm of CCl₄ is 500 ± 17 ppm. A sample can be analysed in less than 30 min. The effects of solvent, irradiation time, reagent concentration, etc., are discussed.