A bismuth (II) selective modified carbon paste electrode with multi-walledcarbon nanotubes for potentiometric analysis in real samples

A novel modified carbon paste electrode with Amino-Functionalized multi-walled carbonnanotubes (F-MWCNT) based on -schiff base ( 2-thienyl pyridine ) was prepared forpotentiometric determination trace amounts of bismuth (III) in real solution. This sensor showedexcellent sensivity, highly selectivity to Bi (III) compared with other cations and very lowdetection limit. The uniqe physicochemical properties of carbon nanotubes (CNTs) improvedsensing and performance of bismuth sensor [1]. Central composite chemometrics design (CCD)and response surface methodology (RSM) was applied to evaluate the effects of significant andindependent parameters, multivariate optimization and to gain better results [2]. Four factorscontaining ionophore, F-MWCNT, graphite powder and pH were investigate in twenty eightcompletely randomized trials CCD. So, the optimized bismuth sensor with the best amounts ofingredients in the optimal condition exhibits a nernestian slope of 19.325 mv/decade in the lineardynamic range of 1 × 10-10 to 1× 10-3 with detection limit of 1.057 × 10-10 The optimizedelectrode shows a fast response time less than 10s and applicable for 8 consecutive weeks withoutany change in PH range 3.8 - 10.0. The molecular geometric optimization and vibrationalfrequencies of synthesized ionophore and complex ( ionophore-Bi (III) ) in the ground state havebeen calculated by using B3LYP with 6-31G ( d , p ) basic set in solution phase [3].

Keywords:

Carbon Paste , Potentiometric , Carbon Nanotubes (CNTs) , Schiff Base , Sensor