Study and optimization of the necessary conditions for the sensitive determination of the lead ion by a modified carbon paste electrode in environmental water samples

Rapid and facile preparation of the cheap modified electrode materials is an important parameter in development of the efficient electrochemical sensor for industrial scale production and mass-market usage. In the present work, the carbon paste electrode modified with multi-walled carbon nanotubes (MWCNTs) was prepared for sensitive determination of lead (Pb) ion in the presence of bismuth (Bi) ion due to synergetic effect of carbon nano-materials and Bi on the voltammetric response. Investigations showed that in presence of Bi ion degassing of the test solution is not needed. Supporting electrolyte, required Bi concentration and accumulation time and potential were optimized for differential pulsed anodic stripping voltammetric tests. Under optimized conditions, modified carbon paste electrode showed sensitive voltammetric response in the range of 0.1-10 μM toward Pb ion. Moreover, efficiency of the developed method was evaluated for the determination of Pb ion in several water samples. The obtained recovery results of 92-97 % revealed good agreement between responses of this sensor and common spectroscopies techniques for the Pb ion analysis. The optimized system has high efficiency in reproducibility and repeatability of the results and applicability for the analysis of the various environmental water samples.