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Ruthenium Hexacyanoferrate (III) Modified Glassy Carbon Electrode for Determination of Captopril
Author(s) -
Dias I. A. R. B.,
Costa W. M.,
Cervini P.,
Cavalheiro E. T. G.,
Marques A. L. B.
Publication year - 2016
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201600107
Subject(s) - differential pulse voltammetry , redox , detection limit , chemistry , glassy carbon , ruthenium , analyte , captopril , analytical chemistry (journal) , electrode , cyclic voltammetry , electrolyte , supporting electrolyte , electrochemistry , inorganic chemistry , chromatography , organic chemistry , catalysis , medicine , blood pressure , radiology
A glassy carbon electrode modified with a ruthenium (III) hexacyanoferrate film was investigated for the determination of captopril in pharmaceutical formulations. The RuOHCF film was deposited on the surface of the electrode after applying 50 successive cycles and subsequent stabilization in a mixture of NaNO 3 0.50 mol L −1 +HCl 0.050 mol L −1 used as supporting electrolyte. The main processes responsible for the redox electrode response are attributed to the system Ru II /Ru III/ Ru IV , and appeared at −0.080, 0.86 and 1.01 V ( vs . SCE). The redox process at −0.080 V was selected for the determination of captopril in the present study, once it provided higher sensibility and occurs in a lower potential than the other ones which can prevent interferences. The experimental parameters used in the determination of the analyte, using differential pulse voltammetry were optimized: pulse amplitude: 50 mV, scan rate: 5 mV s −1 and potential window: −0.5 to 0.2 V ( vs . SCE). The analytical application of the sensor in real samples demonstrated a linear range between 0.060 and 0.80 µmol L −1 (r=0.998) with a detection limit of 0.047 µmol L −1 . A mechanism based on co‐precipitation of captopril and the Ru (III) complex in the film is presented once the signal of the Ru II/III redox couple decreases with increasing the analyte concentration. Recoveries of 99 to 100 % were achieved in pharmaceutical samples and the proposed procedure agreed with the HPLC official method within 95 % confidence level, according to the t‐Student test.