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

Abstract

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.

Cost‐effective and Facile Production of a Phosphorus‐doped Graphite Electrode for the Electrochemical Determination of Pyridoxine

“…As the pH goes from 3.0 to 8.0, the peak current decreases, and a peak shape deterioration is observed. Py has two pKa values which are pKa 1 = 5.0 and pKa 2 = 8.96 [35]. Pyridoxine is expected to be in an anionic form only in strong basic solution (pH > pKa 2 ) due to the deprotonation of the À OH group bonded to the pyridinic ring and the cationic form in acidic solutions (pH < pKa 1 ) the pyridinic nitrogen is protonated.…”

Recent Advances in the Use of CoPc-MWCNTs Nanocomposites as Electrochemical Sensing Materials

“…Porto and his group [ 72 ] developed a sensor to determine pyridoxine by modifying a pyrolytic graphite electrode (PGE) with CoPcMWCNTs composite. The mechanism of the pyridoxine oxidation on the surface of the CoPcMWCNT/PGE is illustrated in Scheme 7 below.…”

Recent advances in electroanalytical drug detection by porphyrin/phthalocyanine macrocycles: developments and future perspectives

“…In another study, Porto et al 2 developed and validated the determination of pyridoxine (vitamin B 6 , Fig. 7A) employing CMEs based on a pyrolytic graphite electrode (PGE), CoPc and MWCNT composite designed as PGE − MWCNT/CoPc by DPV.…”