Bismuth doped carbon xerogel nanocomposite incorporated in chitosan matrix for ultrasensitive voltammetric detection of Pb(II) and Cd(II)

A new modified electrode based on a modified electrode incorporating Bi doped mesoporous carbon xerogel (Bi-CX), confined in a chitosan matrix (Chi) and deposited on a glassy carbon (GC), was elaborated and investigated for Pb(II) and Cd(II) voltammetric trace detection. Bi-CX was prepared by sol-gel method, coupled with drying under ambient conditions and followed by thermal pyrolysis. The morpho-structural characteristics of the new nano-material material such as specific surface area, pore size distribution, pore volume, phase composition and crystallite mean size were examined by using from N2 adsorption/desorption isotherms, TEM, SEM and XRD measurements. The electrochemical behavior of the GC/Chi-(Bi-CX) modified electrode as well as its relevance for Pb(II) and Cd(II) trace detection were investigated by cyclic voltammetry and square wave anodic stripping voltammetry. The linear range, sensitivity, and detection limit of the new sensor were estimated as (0.2-2) ppb, 5.6 A/ppm and 0.07 ppb, for Pb(II), and (11.2-124) ppm, 22.7 nA/ppm and 5.06 ppm, for Cd(II), respectively. The excellent analytical parameters for Pb(II) detection were exploited for the determination of the Pb(II) concentration in drilled well water samples. The results were found in good agreement with those obtained by atomic absorption spectrophotometry.