Electrochemical Sensor Based on Multi‐walled Carbon Nanotubes and Cobalt Phthalocyanine Composite for Pyridoxine Determination

• Published in: Electroanalysis (New York, N.Y.) N.Y.), 2019-05, Vol.31 (5), p.820-828
• Main Authors: Porto, Laís Sales, da Silva, Daniela Nunes, Silva, Maria Cristina, Pereira, Arnaldo César
• Format: Article
• Language: English
• Subjects: cobalt phthalocyanine; multi-walled carbon nanotubes; pyridoxine; Pyrolytic graphite electrode
• ISSN: 1040-0397; 1521-4109
• DOI: 10.1002/elan.201800789

In this work, an electrochemical sensor based on pyrolytic graphite electrode (PGE), cobalt phthalocyanine (CoPc) and multiwalled carbon nanotube (MWCNT) composite designed as PGE‐MWCNT/CoPc was developed and validated for pyridoxine (vitamin B6) determination employing Differential Pulse Voltammetry (DPV). The electrochemical behaviour of pyridoxine at the PGE‐MWCNT/CoPc has been evaluated and the charge transfer coefficient, α, and the charge transfer rate constant, κ, were calculated as 0.30 and 11.67±0.43 s−1, respectively, which indicates that, although this system is irreversible, it is viable kinetically to be used as a sensor. The optimized experimental conditions were pH 5.5 in 0.30 mol L−1 phosphate buffer. The linear range found was 10 to 400 μmol L−1 of pyridoxine, with r=0.9987. The limits of detection and quantification were 0.50 and 1.67 μmol L−1, respectively, showing the good sensitivity of the method. The method was successfully applied for the pyridoxine determination in real samples of pharmaceutical formulation with RSD% lower than 5 % indicating that it can be used for routine quality control pharmaceutical formulations containing pyridoxine. Furthermore, it has the advantages of a fast response, a low detection limit and low cost.