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Pyridoxine (vitamin B 6 , VB 6) was detected in pharmaceutical preparation and human urine samples by employing differential pulse voltammetry (DPV) at unmodified boron doped electrode. In Britton-Robinson buffer solution (BRBS) at pH 6 VB 6 provides well defined oxidation peak at around +1.05 V vs. Ag/AgCl (3M KCl). The influence of most of the interferents present in real samples, supporting electrolyte and DPV parameters were investigated. A VB 6 sensor with and linear range from 7 to 47 and a detection limit of 3.76 was obtain after optimization. Repeatability of the proposed procedure calculated after 7 measurements of 9 and 30 µM of VB 6 were 3.6 and 2.4 %, respectively. Proposed methodology was successfully applied for the determination of VB 6 in real samples, and from obtained results it can be concluded that proposed analytical procedure can be inexpensive alternative to the widely used separation methods.

A carbon paste electrode bulk was modified with MnO2 and investigated for use as an electrochemical sensor for riboflavin (vitamin B2) using differential pulse voltammetry (DPV). Riboflavin displays a well expressed oxidation peak at −0.15 V (versus Ag/AgCl) in solutions with a pH value of 2. Effects of pH value, pulse amplitude and pulse time were optimized by employing DPV. The signals obtained are linearly related to the concentrations of riboflavin in the range from 0.02 to 9 μM. Other features include a 15 nM detection limit, and good reproducibility (±3 %) and repeatability (±2 %). Interferences by common compounds were tested, and the method was successfully applied to the determination of riboflavin in pharmaceutical formulations where is gave recoveries in the range from 95 to 97 %.Graphical abstractManganese(IV) oxide was used as a modifier for the carbon paste electrode (MnO2/CPE) for improving its performance toward riboflavin oxidation. Cyclic voltammetry and differential voltammetry were used for characterization and determination of riboflavin, respectively.