Rapid electrochemical platform for nicotine sensing in cigarettes and chewing gums

A novel protocol for the simple and rapid determination of nicotine using square-wave voltammetry at boron-doped diamond electrode was developed. The effect of pH of supporting electrolyte, scan rate and square-wave voltammetric parameters was examined. Behavior study revealed that nicotine provided two irreversible oxidation peaks, the first one well-shaped at +1.14 V and the second one poorly-defined at +1.61 V vs. Ag/AgCl electrode in the presence of phosphate buffer (pH 9.0). Under optimal experimental conditions (modulation amplitude of 40 mV, frequency of 50 Hz and scan rate of 0.225 V · s^-1), the current response of nicotine was proportionally linear in the concentration range from 9.9 × 10^-6 to 1.7 × 10^-4 mol · L^-1 (R² = 0.996) with the detection limit of 6.1 × 10^-6 mol · L^-1 (0.989 mg · L^-1) and the relative standard deviation of 8.8 % (number of measurements n = 10, 5.7 × 10^-5 mol · L^-1 nicotine). The proposed procedure was applied to the quantification of nicotine in cigarettes and chewing gums with the determined values in good agreement with those declared by producer. In this respect, the developed protocol could represent an effective and rapid alternative to chemically modified electrodes in analysis of alkaloids.