Boron-doped diamond electrochemical sensor for sensitive determination of nicotine in tobacco products and anti-smoking pharmaceuticals

A sensitive, selective and reliable electrochemical method for the determination of nicotine using differential pulse voltammetry on a bare boron-doped diamond electrode has been developed. Nicotine yielded a single oxidation peak at a highly positive potential of +1.45 V (vs. Ag/AgCl/3 M KCl) in Britton-Robinson buffer solution at pH 8. The influence of supporting electrolyte, pH and scan rate on the current response of NIC was investigated. At optimized experimental conditions, a linear relation between peak current and concentration of nicotine was found for the range from 0.5 to 200 mu M (0.08-32.9 mg L-1) with a detection limit of 0.3 mu M (0.05 mg L-1) and a good repeatability (relative standard deviation of 2.1% at 25 mu M concentration level, n = 10) was achieved without any electrode surface modification. The practical usefulness of the developed procedure was successfully demonstrated with the determination of nicotine in tobacco products and anti-smoking pharmaceuticals with results similar to those obtained by a high-performance liquid chromatography and to the contents declared by the manufacturer, respectively. Prior to analysis, the sample pretreatment includes only sonication and/or simple liquid-liquid extraction. The proposed sensor represents an effective electrochemical tool and a promising alternative for quality control analysis of products in tobacco and pharmaceutical industry. (C) 2013 Elsevier B.V. All rights reserved.