scholarly journals Utility of Activated Glassy Carbon and Pencil Graphite Electrodes for Voltammetric Determination of Nalbuphine Hydrochloride in Pharmaceutical and Biological Fluids

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hoda M. Elqudaby ◽  
Hassan A. M. Hendawy ◽  
Eglal R. Souaya ◽  
Gehad G. Mohamed ◽  
Ghada M. G. Eldin

This work compares voltammetric response of nalbuphine hydrochloride (NP·HCl) at both activated glassy carbon and pencil graphite electrodes. The electrochemical oxidation of the drug was studied using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV) techniques. For analytical purpose a well-resolved irreversible diffusion controlled voltammetric peak was established in Britton-Robinson (B-R) buffer solution of pH 6.00 using pencil graphite electrode (PGE). Using activated glassy carbon electrode (GCE) a well-resolved irreversible diffusion controlled voltammetric peak was obtained at pH 7.00 using the same buffer solution. According to the linear relationship between the peak current and NP·HCl concentration, DPV and SWV methods were developed for their quantitative determination in pharmaceutical and human biological fluids. The linear response was obtained in the range from1.6×10-5to1.5×10-4 mol L−1using PGE and from12.5×10-6to13.75×10-5 mol L−1using a GC electrode, respectively. Precision and accuracy of the developed method were checked by recovery studies.

2011 ◽  
Vol 64 (7) ◽  
pp. 965 ◽  
Author(s):  
Sabriye Percin Ozkorucuklu ◽  
Levent Ozcan ◽  
Yucel Sahin ◽  
Guleren Alsancak

The electrochemical behaviours of five sulfonamides (sulfanilamide, sulfadiazine, sulfamerazine, sulfamonomethoxine, sulfamethoxazole) were investigated with overoxidized polypyrrole (OPPy) modified pencil graphite electrodes. The performance of the OPPy electrode was evaluated by differential pulse voltammetry in Britton–Robinson buffer solutions prepared in different ratio of acetonitrile-water binary mixture, between pH 1.5 and 7.0. The highest anodic signals of sulfonamides were obtained in Britton–Robinson buffer solution prepared in 50% (v/v) acetonitrile-water at pH 2.5 and 3.0. The OPPy electrodes exhibited good performance for sulfonamides with wide linear ranges (≈10–5–10–3 M), highly reproducible responses (RSD% ≤0.92) and correlation coefficients (≥0.9990). The calculated limits of detection were ~10–6 or 10–7 M at 3σ. In order to verify the reliability of the OPPy electrode as a sensor, it is used for determination of sulfamethoxazole in a pharmaceutical tablet. The recovery was found as 95.96% with the RSD% of 0.68. The overoxidized polypyrrole modified pencil graphite electrode showed a stable and reproducible response without any influence of interferent commonly existing in pharmaceutical containing sulfamethoxazole.


2021 ◽  
Author(s):  
Yan Jin ◽  
Tong QI ◽  
Yuqing Ge ◽  
Jin Chen ◽  
Li juan Liang ◽  
...  

In this paper, ultrasensitive electrochemical determination of phosphate in water is achieved by hydrophilic TiO2 modified glassy carbon electrodes for the first time. Differential pulse voltammetry (DPV) method is proposed...


2011 ◽  
Vol 76 (5) ◽  
pp. 383-397 ◽  
Author(s):  
Ferenc T. Pastor ◽  
Hana Dejmková ◽  
Jiří Zima ◽  
Jiří Barek

The possibility of determination of chloramphenicol by differential pulse voltammetry at four different carbon paste electrodes, in the full pH range (2–12) of Britton–Robinson (BR) buffer was investigated. Electrodes were prepared by mixing spectroscopic graphite powder or glassy carbon microbeads with mineral oil (Nujol) or tricresyl phosphate. Under optimal conditions (BR buffer pH 12, the electrode prepared from glassy carbon microbeads and tricresyl phosphate), linear calibration graph was obtained only in 10–5 M chloramphenicol concentration range. Determination of lower concentrations of chloramphenicol was complicated by irreproducible peak of oxygen from the carbon paste which overlapped with peak of chloramphenicol. Addition of sodium sulfite removed the oxygen peak without influence on the peak of chloramphenicol. Under optimal conditions (electrode paste made from glassy carbon microbeads, BR buffer pH 10 and 0.5 M sodium sulfite), straight calibration line was obtained in the 10–6 and 10–5 M chloramphenicol concentration range. Limit of determination was 5 × 10–7 mol/l.


2020 ◽  
Vol 18 (4) ◽  
pp. 253-258
Author(s):  
Gamze Erdoğdu

A sensitive and simple modified sensor was prepared by electrodeposition of diphenylamine sulfonic acid (DPSA) to the glassy carbon electrode surface by cyclic voltammetry (CV) technique. The electrooxidation of epinephrine (EP) was accomplished by CV and differential pulse voltammetry at poly(DPSA) modified sensor. As a result of the findings, the current values were enhanced and both substances were separated at the modified sensor compared to the bare electrode. There was linearly between the oxidation current and concentration of EP from 0.2 to 100 μM in phosphate buffer solution at pH 7.0. The limit of detection was 5.0 nM and the sensitivity was 0.4205 μA/μM. The determination of EP was successfully and satisfactorily carried out in real samples such as human blood serum and urine at the poly(DPSA) sensor. To the best knowledge of this work, this is the first study that detect the EP in the presence of ascorbic acid at poly(DPSA) sensor in the literature.


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