Fast synthesis of platinum nanopetals and nanospheres for highly-sensitive non-enzymatic detection of glucose and selective sensing of ions

Novel methods to obtain Pt nanostructured electrodes have raised particular interest due to their high performance in electrochemistry. Several nanostructuration methods proposed in the literature use costly and bulky equipment or are time-consuming due to the numerous steps they involve. Here, Pt nanostructures were produced for the first time by one-step template-free electrodeposition on Pt bare electrodes. The change in size and shape of the nanostructures is proven to be dependent on the deposition parameters and on the ratio between sulphuric acid and chloride-complexes (i.e., hexachloroplatinate or tetrachloroplatinate). To further improve the electrochemical properties of electrodes, depositions of Pt nanostructures on previously synthesised Pt nanostructures are also performed. The electroactive surface areas exhibit a two order of magnitude improvement when Pt nanostructures with the smallest size are used. All the biosensors based on Pt nanostructures and immobilised glucose oxidase display higher sensitivity as compared to bare Pt electrodes. Pt nanostructures retained an excellent electrocatalytic activity towards the direct oxidation of glucose. Finally, the nanodeposits were proven to be an excellent solid contact for ion measurements, significantly improving the time-stability of the potential. The use of these new nanostructured coatings in electrochemical sensors opens new perspectives for multipanel monitoring of human metabolism

Electrochemical Non-enzymatic Glucose Sensors: A Perspective and an Evaluation

An overview of glucose sensors is presented, with specific focus on the promise of non-enzymatic electrochemical glucose sensors. The review addresses their merits and shortfalls with respect to their commercially available enzymatic counterparts. The mechanisms for catalysis are evaluated, and the future of the systems discussed. © 2010 by ESG

Simultaneous Detection of Trace Cadmium(II) and Lead(II) Using an Unmodified Edge Plane Pyrolytic Graphite Electrode

We report the sensitive simultaneous detection of cadmium(II) and lead(II) using an unmodified edge plane pyrolytic graphite (EPPG) electrode via linear sweep anodic stripping voltammetry (LSASV). Simultaneous additions of the heavy metals gave two well separated stripping peaks observed over two linear ranges, 20 to 200μg L-1 and 2 to 20μg L-1. These gave detection limits of 0.3μg L-1 and 0.2μg L-1 for cadmium(II) and lead(II), respectively. The use of unmodified EPPG electrodes shows comparable performance to bismuth and mercury modified electrodes, and offers a simple and effective alternative to modified systems

Electroanalytical Determination of Antimony

Antimony is an element that is common in the environment owing to numerous industrial applications and, in places, natural occurrence. The toxicity of some antimony compounds ought to place the element at the focus of analytical determination. Electrochemical methods offer a simple approach to antimony analysis, most frequently by use of anodic stripping voltammetry. To-date however, a comprehensive review of the electroanalytical literature has not been reported. Herein electroanalytical determination of antimony is reviewed, along with relevant aspects of its speciation. © 2011 by ESG

Anodic stripping voltammetry of antimony at unmodified carbon electrodes

Antimony is an element of significant environmental concern, yet has been neglected relative to other heavy metals in electroanalysis. As such very little research has been reported on the electroanalytical determination of antimony at unmodified carbon electrodes. In this paper we report the electrochemical determination of Sb(III) in HCl solutions using unmodified carbon substrates, with focus on non-classical carbon materials namely edge plane pyrolytic graphite (EPPG), boron doped diamond (BDD) and screen-printed electrodes (SPE). Using differential pulse anodic stripping voltammetry, EPPG was found to give a considerably greater response towards antimony than other unmodified carbon electrodes, allowing highly linear ranges in nanomolar concentrations and a detection limit of 3.9 nM in 0.25 M HCl. Furthermore, the sensitivity of the response from EPPG was 100 times greater than for glassy carbon (GC). Unmodified GC gave a comparable response to previous results using the bare substrate, and BDD gave an improved, yet still very high limit of detection of 320 nM compared to previous analysis using an iridium oxide modified BDD electrode. SPEs gave a very poor response to antimony, even at high concentrations, observing no linearity from standard additions, as well as a major interference from the ink intrinsic to the working electrode carbon material. Owing to its superior performance relative to other carbon electrodes, the EPPG electrode was subjected to further analytical testing with antimony. The response of the electrode for a 40 nM concentration of Sb(III) was reproducible with a mean peak current of 1.07 μA and variation of 8.4% (n = 8). The effect of metals copper, bismuth and arsenic were investigated at the electrode, as they are common interferences for stripping analysis of antimony. © 2013 Copyright Taylor and Francis Group, LLC

The Fabrication and Characterization of a Nickel Nanoparticle Modified Boron Doped Diamond Electrode for Electrocatalysis of Primary Alcohol Oxidation

We report the fabrication of a Ni nanoparticle modified BDD electrode and its application in the electrocatalysis of primary alcohol electrooxidation. Modification was achieved via electrodeposition from Ni(NO3)2 dissolved in sodium acetate solution (pH 5). Characterization of the Ni-modified BDD (Ni-BDD) was performed using ex situ atomic force microscopy (AFM) and high resolution scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Large nanoparticles of nickel were observed on the BDD surface ranging 5 to 690 nm in height and 0.18 μm3 in volume, and an average number density of ca. 13 × 106 nanoparticles cm-2 was determined. The large range of sizes suggests progressive rather than instantaneous nucleation and growth. Electrocatalysis of ethanol and glycerol, was conducted in an alkaline medium using an unmodified BDD, Ni-BDD and a bulk Ni macro electrode. The Ni-BDD electrode gave the better electrocatalytic performance, with glycerol showing the greatest sensitivity. Linear calibration plots were obtained for the ethanol and glycerol additions over concentration ranges of 2.8 - 28.0 mM and 23 - 230 μM respectively. This gave an ethanol limit of detection of 1.7 mM and sensitivity of 0.31 mA/M, and the glycerol a limit of detection of 10.3 μM with a sensitivity of 35 mA/M. © 2009 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim

The Stripping Voltammetry of Hemispherical Deposits Under Electrochemically Irreversible Conditions: A Comparison of the Stripping Voltammetry of Bismuth on Boron-Doped Diamond and Au(111) Electrodes

A study of the stripping voltammetry of hemispherical deposits under electrochemically irreversible conditions is presented. Experiments show a difference in the stripping voltammetry of bismuth from a single crystal Au(111) electrode where the bismuth covers the surface in relatively flat film and a boron-doped diamond (BDD) electrode where the hemispherical deposits are seen on the surface. It is shown using mathematical modeling and numerical simulation that this difference cannot be accounted for by simply considering the different distributions of bismuth on the electrode surfaces. Rather, it is concluded that the difference in voltammetry is mainly due to the morphology/orientation of the deposits formed leading to differences in the kinetics and thermodynamics of the stripping process. © 2009 American Chemical Society

New electrochemical methods.

This review is predominantly focused upon articles dating from 2009 to 2011. The authors have attempted to highlight areas of recent and significant development, with the aim of providing the reader with a clear and concise view of the current state-of-the-art in areas ranging from fundamental electrochemistry to applied methods for biological analysis. Specific areas of interest include recent developments in surface analysis techniques, single-molecule and nanoparticle stochastic analysis, and nanopore technolog