No abstract

A simple and highly sensitive sensor has been used for the determination of oxomemazine hydrochloride (OXO) in presence of paracetamol (PAR) and guaifenesin (GU). Carbon paste electrode was modified with multiwalled carbon nanotube (MWCNT), alizarine red S (AZ) and chitosan (CH). Scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to characterize the nanostructure and performance of the sensor. Under the optimized experimental conditions OXO gave linear response over the range of 2.00×10−6–1.00×10−4 mol L−1. The detection limit was found to be 4.35×10−7 mol L−1. The practical application of the modified electrode was demonstrated by measuring the concentration of OXO in pharmaceutical samples and urine. This revealed that suggested sensor shows excellent analytical performance for the determination of OXO in terms of a very low detection limit, high sensitivity and selectivity.

The electrochemical oxidation of repaglinide has been carried out in Britton-Robinson buŠer at carbon paste and glassy carbon electrodes. Repaglinide exhibits a well-deˆned irreversible oxidation peak over the entire pH range (2 11). DiŠerential pulse voltammetry was used to determine repaglinide in pure form. The peak current varied linearly in the following ranges: 8.0×10 -7  3.2×10-6 M and 4.0×10 -7  4.0×10 -6 M in case of carbon paste electrode and glassy carbon electrode, respectively. In case of carbon paste electrode the limits of detection (LOD) and quantiˆcation (LOQ) were 1.348×10 -7 M and 4.494×10 -7 M, respectively. For glassy carbon electrode the LOD and LOQ were 1.062×10 -7 M and 3.54×10 -7 M, respectively. The percentage recoveries were found in the following ranges: 99.09 100.07％ and 99.0 100.50％ for carbon paste electrode and glassy carbon electrode, respectively. The relative standard deviations were found in the following ranges: 0.636 1.395％ and 0.431 1.104％ in case of carbon paste electrode and glassy carbon electrode, respectively. DiŠerential pulse voltammetry was successfully applied for the determination of repaglinide in tablets and human serum.

No abstract

No abstract