Electrochemical characterization and analytical application of arsenopyrite mineral in non-aqueous solutions by voltammetry and potentiometry

Abstract

Based on the cyclic voltammetric method, in the present study we have employed carbon paste for arsenopyrite mineral characterization in non-aqueous solution. Arsenopyrite yields well-defined cyclic voltammetric responses with well-defined oxidation (in the potential region from −0.7 to 0.7V, versus Ag/AgCl) and reduction (from −1.0 to 0.8V) peaks using this electrode. In addition, arsenopyrite mineral was studied as a new indicator electrode for the potentiometric titrations of acids (benzoic, anthranilic and salicylic acids) and bases (N,N′-diphenylguanidine, tributylamine and collidine) in acetonitrile and propionitrile. Potassium hydroxide, tetrabutylammonium hydroxide (TBAH) and perchloric acid proved to be very suitable titrating agents for these titrations.The investigated electrode showed a linear dynamic response for p-toluenesulfonic acid concentrations in the range 0.1–0.001M, with a Nernstian slope of 38.5mV in acetonitrile and 44.6mV in propionitrile. The electrode showed a relatively fast response time and can be used without any time limit or without considerable divergence in potentials. The response time of the electrode was less than 10s in both solvents. The standard deviation of the determination of the investigated acids and bases was less than 0.6% from those obtained with a glass electrode.The advantages of the electrodes are long-term stability, fast response and reproducibility, while the sensors are easy to prepare and are of low cost.