title: Differential pulse adsorptive stripping voltammetric determination of nanomolar levels of atorvastatin calcium in pharmaceutical and biological samples using a vertically aligned carbon nanotube/graphene oxide electrode.
abstract: A novel vertically aligned carbon nanotube/graphene oxide (VACNT-GO) electrode is proposed, and its ability to determine atorvastatin calcium (ATOR) in pharmaceutical and biological samples by differential pulse adsorptive stripping voltammetry (DPAdSV) is evaluated. VACNT films were prepared on a Ti substrate by a microwave plasma chemical vapour deposition method and then treated with oxygen plasma to produce the VACNT-GO electrode. The oxygen plasma treatment exfoliates the carbon nanotube tips exposing graphene foils and inserting oxygen functional groups, these effects improved the VACNT wettability (super-hydrophobic) which is crucial for its electrochemical application. The electrochemical behaviour of ATOR on the VACNT-GO electrode was studied by cyclic voltammetry, which showed that it underwent an irreversible oxidation process at a potential of +1.08 V in pHcond 2.0 (0.2 mol L(-1) buffer phosphate solution). By applying DPAdSV under optimized experimental conditions the analytical curve was found to be linear in the ATOR concentration range of 90 to 3.81 × 10(3) nmol L(-1) with a limit of detection of 9.4 nmol L(-1). The proposed DPAdSV method was successfully applied in the determination of ATOR in pharmaceutical and biological samples, and the results were in close agreement with those obtained by a comparative spectrophotometric method at a confidence level of 95%.
authors.affiliation: Department of Chemistry, Federal University of São Carlos, Rod. Washington Luís km 235, P. O. Box 676, São Carlos, CEP: 13560-970, SP, Brazil. bello@ufscar.br.
authors.forename: Tiago Almeida
authors.initials: TA
authors.lastname: Silva
authors.forename: Hudson
authors.initials: H
authors.lastname: Zanin
authors.forename: Fernando Campanhã
authors.initials: FC
authors.lastname: Vicentini
authors.forename: Evaldo José
authors.initials: EJ
authors.lastname: Corat
authors.forename: Orlando
authors.initials: O
authors.lastname: Fatibello-Filho
mesh_terms: D000327:Adsorption; D000069059:Atorvastatin; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D006538:Heptanoic Acids / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon; D010087:Oxides / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry; D011758:Pyrroles / Q000032:analysis*
chemical_list: D006538:Heptanoic Acids; D037742:Nanotubes, Carbon; D010087:Oxides; D004364:Pharmaceutical Preparations; D011758:Pyrroles; D006108:Graphite; D000069059:Atorvastatin