A Glassy Carbon Electrode for The Determination of Linagliptin Antidiabetic Drug in Pure, tablets and some biological fluids by Adsorptive Stripping Voltammetry

Aim: The present work provides a fast, simple, accurate, and inexpensive analytical method for the determination of Linagliptin (anti-diabetic drug). Methods: Using a square wave adsorptive anodic stripping voltammetric technique (SWAASV) and glassy carbon electrode (GCE) as a working electrode. The experimental and instrumental parameters were studied and discussed to ensure the validity of the method. Results: The method has a very good linearity (R2 = 0.9984), wide concentration range (0.189 - 2.268) µg mL -1 ), low detection limit 0.052 µg mL -1 and low quantitation limit 0.172 µg mL -1 . Conclusion: Linagliptin was determined successfully in pharmaceutical form, spiked urine and plasma with 99.67, 91.96, and 92.78 % recovery respectively by using the proposed method, and the results obtained were compared with other reported methods.

Poly (Adenine) Modified Graphene-Based Voltammetric Sensor for the Electrochemical Determination of Catechol, Hydroquinone and Resorcinol

Objective: This paper presents the application of Poly (Adenine) Modified Graphene Paste Electrode (PAMGPE) for the analysis of Catechol (CC) with Resorcinol (RC) and Hydroquinone (HQ) by a voltammetric technique. Methods: Electropolymerization technique was utilized for the modification of the sensor surface. The electrode surface was characterized by Field Emission Scanning Electron Microscopy (FE-SEM). Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) were used to study the redox behavior of CC, RC and HQ. Results: Oxidation peak current of CC increased linearly with the concentration of CC in the range from 2×10-6- 8×10-6 M and 1×10-5-1.5 ×10-4 M with a detection limit of 2.4×10-7 M. The practical application of the developed sensor was verified as exact for the determination of CC in water sample. Conclusion: The stability, repeatability, and reproducibility of the developed electrode were studied and established good characteristics. Furthermore, the PAMGPE was examined for the simultaneous determination of CC, RC and HQ.

Electrochemical Characterization of Redox FeII/FeIII Mediated by ZrO2NPs/GCE Using Cyclic Voltammetry

In this article, experimental methods based on cyclic voltammetric technique were used to study the electrochemical analysis of a new modified electrode with zirconium dioxide molecules on the glassy carbon electrode (ZrO2NPs/GCE) to characterize iron ions K4[Fe(CN)6]. These methods also allowed the study of current peaks for oxidation reduction of Fe(II)/Fe(III) using potassium chloride (KCl) solution as electrolytes at different concentration, pH, scanning rates, and stability (reliability) of which these parameters are important in assessing oxidation properties. Also, the diffusion coefficient values of oxidation-reduction reaction for iron ions on the new sensor (ZrO2 NPs/GCE) was determined using Randles-Seveik equation as Dfa = 2.03 ×10-5 cm2 /sec and Dfc = 7.12 × 10-5 cm2 /sec, respectively. It was found the modified electrode ZrO2NPs/GCE acts as a good sensor with high detection limit of iron ions in electrolyte. It can be used the modified electrode in different electrochemical applications because of its higher conductivity.