A comparative study on carbon paste electrodes modified with hybrid mesoporous materials for voltammetric analysis of lead (II)

En el siguiente artículo se estudia el análisis voltamperométrico del plomo (II) mediante electrodos de pasta de carbono modificados con materiales híbridos mesoporosos. Se tratra de un voltamperometría de redisolución-adsorción.



We have chem. functionalized four types of ordered mesoporous silicas (referred to as MPS1-MPS4) with 5-mercapto-1-methyltetrazole (MTTZ), and have incorporated these materials into carbon paste electrodes (CPEs) to obtain sensors for the detn. of Pb(II) ion in aq. media by adsorptive stripping voltammetry.  Materials and MPS1-MPS4, were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction, transmission electron microscopy, SEM and elemental anal.  The effect of the mesostructure of the MPS on the performance of the sensors was evaluated with respect to linear ranges, sensitivities, selectivities, precision and limits of detection.  The CPE modified with MPS1 (a silica with mesopores of 37 Å in diam. and pseudo-spherical particle morphol.) exhibited the best inter-electrode reproducibility and sensitivity, a linear range between 1 and 30 ppb and a limit of detection of 0.8 ppb.  The CPE modified with MPS4 (a silica with hexagonal mesopores of 58 Å in diam., cylindrical particle morphol. and bigger size) exhibited the poorest inter-electrode reproducibility and sensitivity, a linear range between 5 and 100 ppb, and a limit of detection of 2.6 ppb.  The differences in the voltammetric responses to Pb(II) therefore appear to result from differences in the coating of the inner surface with MTTZ, the pore diam., and the particle morphol. as well as the size of the hybrid MPS.  As consequence of its highest inter-electrode reproducibility and sensitivity, good linear range and low limit of detection, MPS1 can be selected as the better material to prep. modified CPE for Pb(II) detn. in aq. media by adsorptive stripping voltammetry.

Sanchez, Alfredo; Morante-Zarcero, Sonia; Perez-Quintanilla, Damian; del Hierro, Isabel; Sierra, Isabel Journal of Electroanalytical Chemistry (2013), 689, 76-82