Differential Pulse Stripping Voltammetric Research Articles

Determination of Total Antioxidant Capacities in Turkish and Filter Coffee Samples by Electrochemical Methods

In this study, cyclic (CV), square wave stripping (SWSV) and differential pulse stripping voltammetric (DPSV) methods were used to determine total antioxidant capacity (TAC) in Turkish and Filter coffees brewed with differently roasted coffee beans such as light, medium and dark. Voltammetric parameters were optimized in pH 4.0 Britton-Robinson buffer solution using carbon paste electrode (CPE). Electrochemical behavior of gallic acid and quercetin as standard antioxidant substances were investigated on CPE under optimum conditions by CV, SWSV and DPSV. With all three electrochemical techniques (CV, SWSV, DPSV), two oxidation peaks were observed for gallic acid approximately at 350 mV and 700 mV, while anodic peaks were obtained for quercetin at 340 mV, 725 mV and 1015 mV. However, anodic peak currents at 350 mV for both substances were preferred using CPE to determine total antioxidant capacities in coffee samples in terms of equivalent gallic acid and quercetin. It was found that coffee samples prepared by light roasted coffee beans showed maximum antioxidant capacity (TAC). TAC values for Turkish coffee prepared with less roasted coffee beans were calculated as 17.868±0.281 g/L and 65.165±1.024 g/L equivalent gallic acid and quercetin using CV method. Also, TAC values for filter coffee were 32.290±0.839 g/L and 118.471±3.529 g/L, respectively. Moreover, TAC values in all coffee samples were also analyzed with DPSV and SWSV as well as CV. As a result, TAC analysis is carried out directly on food samples with electrochemical methods, fast, cheap and without pre-treatment.

Electrochemical Sensor for Determination of Pb2+ Based on Gold Nanoparticles.

We report the formation of gold nanoparticles on indium tin oxide conducting glass (ITO) surface via electrodeposition method at room temperature. The prepared nano-Au electrodes has been fabricated for sensitive detection of Pb2+, and showed highly selective response toward Pb2+. The electrochemical detection of Pb2+ were determined by differential pulse stripping voltammetric (DPSV). The nano-Au electrochemical sensor could detect Pb2+ from 0.5 to 10 μM with detection limits of 0.06 μM (S/N= 3) and sensitivity of 0.27996 mA μM-1. The proposed sensor is simple, reliable, sensitive, selective, and low-cost, thus holds potential for practical application in Pb2+ detection.

Monitoring of triamterene and hydrochlorothiazide at carbonic materials modified electrode

Hydrochlorothiazide/triamterene, also known as co-triamterzide, is a combination medication of hydrochlorothiazide and triamterene. It is used to treat high blood pressure and swelling. Specifically it is used in those who develop low blood potassium when on only hydrochlorothiazide. Due to side effect, their measuring is very important. This report introduces a new sensor based on glassy carbon electrode (GCE) modified with a multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) hybrid nanocomposite for electrochemical determination of triamterene (TRM) and hydrochlorothiazide (HCT) simultaneously. Impedance spectroscopy and scanning electron microscopy (SEM) were used for electrode modification process. The differential pulse stripping voltammetric (DPSV) responses of HCT and TRM were in linear with their concentrations, ranging from 0.5 to120 μM and 1.5 to 120μM respectively with correlation coefficients >0.99. The synergistic influence of MWNTs and graphene contributes to the excellent performance for the sensor, in simultaneous determination of HCT and TRM in pharmaceutical combinations.

Sensitive Determination of Trace Pb2+ in Seawater Using Columnar Glassy Carbon Electrode

AbstractWe herein report a mercury‐free approach for the sensitive determination of trace Pb2+ in seawater using differential pulse stripping voltammetric (DPSV) method with a novel columnar glassy carbon electrode (CGCE). Compared with the conventional disk glassy carbon electrode with the same diameter, it has much larger electrochemical area (0.627 ± 0.003 cm2). The CGCE shows good accumulation ability and consequently acceptable behavior which makes it suitable as a working electrode in the DPSV determination of Pb2+ with the great advantage of the avoidance of harmful mercury. Using acidified artificial seawater as supporting electrolyte, there was a good linear relationship between the peak currents and the concentration of Pb2+ in the range of 0.6∼140.0 μg L‐1 with a detection limit of 0.3 μg/L (S/N = 3) when the accumulation time was 300 s. The method was employed to determine trace levels of Pb2+ in real seawater samples successfully.

Determination of iodide ions at poly(3-methylthiophene)-modified electrode by differential pulse stripping voltammetry

A voltammetric electrode based on a poly(3-methylthiophene) (PMT) film for the differential pulse stripping voltammetric (DPSV) determination of iodide was developed. Gold electrodes were first coated with PMT, and iodide was then doped into the polymer film by electrochemical oxidation of iodide at 0.75 V. The effects of various electrochemical parameters, such as electroyte type and its pH, deposition potential, deposition time, and precipitation time, were examined. Using DPSV, the PMT electrode was found to be suitable for the measurement of iodide concentrations above 1 × 10−9 M.

Mercury‐Free Detection of Europium (III) at a Glassy Carbon Electrode Modified with Carbon Nanotubes by Adsorptive Stripping Voltammetry

A multi‐wall carbon nanotubes (MWCNTs) and Nafion composite film‐modified glassy carbon electrode (GCE) is described for the detection of europium (III) by differential pulse adsorptive stripping voltammetry. In pH 4.2 NaAc–HAc buffer solution, Eu3+ is first exchanged by Nafion and absorbed on the surface of MWCNTs film. The accumulated Eu3+ then undergoes a one‐electron reduction around −0.7 V during the potential sweep from −0.1 to −1.0 V. The MWCNTs–Nafion film significantly improves the sensitivity of Eu3+ determination compared with a bare GCE and a Nafion‐coated GCE. The differential pulse stripping voltammetric (DPSV) signal changes linearly with the concentration of Eu3+ in a wide range from 4.0×10−8 to 1.0×10−4 M. The detection limit is estimated to be 10 nM for 60 s accumulation at −0.1 V. Lots of inorganic ions and all of the other rare earth ions do not give characteristic voltammetric responses in the developed operation. The sensitivity and stability of this MWCNTs–Nafion GCE has demonstrated its application for a rapid and mercury‐free detection of trace Eu3+ in NIES CRM No. 8 vehicle exhaust particulates.

Intercomparison Studies of Stripping Voltammetry and Atomic Absorption Spectrometry of Zn, Cd, Pb, Cu, Ni and Co in Baltic Sea Water

Abstract For the determinations of trace metals in natural waters precaution steps concerning sampling, storage, pretreatment and analysis are demonstrated. Differential pulse stripping voltammetric (DPSV) and atomic absorption spectrometric (AAS) techniques are compared. Zn, Cd, Pb and Cu are determined by differential pulse anodic stripping voltammetry (DPASV) using either a hanging mercury drop electrode (HMDE) or an in situ plated mercury film electrode (MFE). A gold disc electrode (GDE) is also applied to Cu-determination. Differential pulse cathodic stripping voltammetry (DPCSV) is used for the determination of Ni and Co. Electrothermal AAS-methods are used for Cd, Pb, Cu, Ni and Co, while the flame AAS-method is employed for Zn. Analysis of coastal Baltic Sea waters gives similar results using the different modes of DPSV and AAS.