Communication—Selective Electrochemical Detection of Catechin Compounds in Herbal Medicines

Most electrochemical sensors reported for catechin determination in herbal medicines actually involve the detection of not only catechins but also other flavonoids. This work proposes a strategy to selectively detect and quantify flavan-3-ol, known as catechins, in the presence of other flavonoids by complexation with AlCl3. Flavonoids (e.g.,rutin, quercetin) form stable complex with AlCl3 which affect the electrooxidation of these molecules. Hence, the electrochemical oxidation of catechin is free from the interference of other flavonoids as shown by differential-pulse voltammetry using glassy-carbon electrode. The approach was applied to herbal medicines and mass-spectrometry confirmed the presence of catechins in such samples.

Cloud point extraction associated with differential pulse voltammetry: preconcentration and determination of trace uranyl in natural water

A procedure for electroanalytical determination of the uranyl ions pre-concentrated from natural water by cloud point extraction (CPE) was developed in this work. The CPE parameters, such as surfactant concentration,...

Electrochemical determination of tramadol using modified screen printed electrode

The detection of tramadol using a screen printed electrode modified with La3+/ZnO nano-flowers and multi-walled carbon nanotubes (La3+/ZnO NFs-MWCNTs/SPE) is reported in this work. In order to examine tramadol electrochemical oxidation, the modified electrode was implemented with the utilization of differential pulse voltammetry, chronoamperometry and cyclic voltammetry as diagnostic techniques. The proposed electrode displays favorable electrocatalytic behavior concerning tramadol oxidation with an approximately 330 mV potential shift to a lesser positive potential. In the 0.5 to 800.0 μM range for tramadol, differential pulse voltammetry displays linear dynamic activity. Tramadol detection limit of 0.08 μM was derived within optimized testing conditions for this simple construction sensor. Lastly, this fabricated sensor was utilized with desirable results to determine tramadol in tramadol samples and urine samples.

Differential Pulse Voltammetry as an Alternative Method for Tracking Hydrochlorothiazide Electrolytic Degradation

This study aims to compare differential pulse voltammetry as a tracking method with chromatography and photometry. The three methods were used to track the degradation of the model compound hydrochlorothiazide (HCT) where 250ml of 0.50mM HCT solution (pH of 3.50 and ionic strength of 0.010M) was electrolyzed with 50.0mAmp constant current. The degradation process demonstrated great fit (R2 >0.99) with pseudo-first-order kinetics when the three tracking methods were utilized. However, different rate constants were reported for these methods: 0.032min-1, 0.016 min-1, and 0.0052min-1 for the chromatographic, photometric, and voltammetric techniques, respectively. The observed variation was attributed to the nature of the utilized probing methods. The differential pulse voltammetry is promising as an electrolytic decomposition tracking method; however, the working probe to target pollutants needs to be improved.