title: Evaluation of the electrochemical behavior and analytical potentialities of a carbon paste electrode modified with a ruthenium (III) piperidinedithiocarbamate complex.
abstract: The preparation and electrochemical characterization of a carbon paste electrode modified with bis(N,N-piperidinedithiocarbamate)-mu-tris(N,N-piperidinedithiocarbamate)diruthenium(III) complex, alpha-[Ru2(Pip)5]Cl are described. The best voltammetric response was obtained for a 10% (m/m) alpha-[Ru2(Pip)5]Cl content in the paste, potassium acid phthalate solution pH 4.0 as supporting electrolyte and scan rate of 100 mV s-1. The analytical potentialities of the electrode have been evaluated using L-ascorbic acid (vitamin C) as a probe. A sensitive linear voltammetric response for L-ascorbic acid was obtained in the concentration range 4.50-113x10(-5) mol l-1 (7.92-200 mg l-1) with a slope of 1.12x10(4) microA mol-1, and a detection limit (3sigma/slope) of 7.00x10(-6) mol l-1 using cyclic voltammetry. The concentrations of L-ascorbic acid in pharmaceutical formulations (tablets and liquid) were determined using the modified electrode and compared with an iodimetric procedure with good agreement at the 95% confidence and relative error lower than 1%.
authors.affiliation: Departamento de Química e Física Molecular, Instituto de Química de São Carlos, USP Caixa Postal 780, CEP 13560-970, São Carlos, SP, Brazil.
authors.forename: Luiz Antônio
authors.initials: LA
authors.lastname: Ramos
authors.forename: Eder Tadeu Gomes
authors.initials: ET
authors.lastname: Cavalheiro
authors.forename: Gilberto Orivaldo
authors.initials: GO
authors.lastname: Chierice
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002244:Carbon / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D004364:Pharmaceutical Preparations / Q000737:chemistry; D010880:Piperidines / Q000737:chemistry*; D011199:Potentiometry; D015203:Reproducibility of Results; D012428:Ruthenium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013859:Thiocarbamates / Q000737:chemistry*
chemical_list: D004364:Pharmaceutical Preparations; D010880:Piperidines; D013859:Thiocarbamates; D002244:Carbon; D012428:Ruthenium; D001205:Ascorbic Acid