Electrode GCE

Experimental details on the anodic stripping analysis of metals such as Bi, Pb, Cd, Zn, Mn, Sb and Sn in Cu at the HMDE, and Ag in Cd at a glassy carbon electrode (GCE), have been given by Verbeek and co-workers122. 

Figure 1. Cyclic voltammograms in MeCN(0.1M tetra-ethylammonium perchlorate) for the oxidation of (a) a copper electrode, (b) 3 mM "OH at a glassy carbon electrode, (c) 0.5 mM "OH at a copper electrode, and (d) 3 mM "OH at a copper electrode. Scan rate, 0. IV s"1 electrode area, 0.08 cm2 copper electrode prepared by electroplating Cu(C104) onto a glassy carbon electrode (GCE). ...

Corresponding to a cyclic voltammogram (CV), recorded at a glassy carbon electrode (GCE) immersed into a 1.0 mM Cu + solution in acetic acid/sodium acetate... 

Figure 8.1 Cyclic voltammetry (a) and Osteryoung square wave voltammetry (b) of Cgo (acetonitrile/toluene + 0.1 M ( -Bu)4NPF6), using a glassy carbon electrode (GCE) working and ferrocene/ferrocenium (Fc/Fc +) couple as an internal reference. Reprinted with Permission from Ref. 4. Copyright 1992 American Chemical Society.

A nitrate-selective potentiometric MIP chemosensor has been devised [197, 198]. For preparation of this chemosensor, a polypyrrole film was deposited by pyrrole electropolymerization on a glassy carbon electrode (GCE) in aqueous solution of the nitrate template. Potentiostatic conditions of electropolymerization used were optimized for enhanced affinity of the resulting MIP film towards this template. In effect, selectivity of the chemosensor towards nitrate was much higher than that to the interfering perchlorate ( o3 cio4 = 5.7 x 10-2) or iodide ( N03, r = x 10 2) anion. Moreover, with the use of this MIP chemosensor the selectivity of the nitrate detection has been improved, as compared to those of commercial ISEs, by four orders of magnitude at the linear concentration range of 50 pM to 0.5 M and LOD for nitrate of (20 10) pM [197]. 

The potential danger associated with mercury has led to the development of other strategies that avoid the use of a mercury solution. These strategies use glassy carbon electrodes (GCE) coated with a mercury film modified with Nafion [3,4], cellulose acetate [5], naphthol derivative [6], etc., where mercury is generated in situ and this way avoiding the manipulation of mercury solutions as done previously. Composite electrode containing HgO as a built-in mercury precursor, which supply mercury-film formation, has even been reported to avoid the use of mercury solution [7]. 

Cai et al. [28] have synthesised AuNPs-labelled ssDNA as a probe to be hybridised with their complementary strand on chitosan-modified glassy carbon electrode (GCE). In their experiments, SH-ssDNA was self-assembled onto an AuNP (16 nm in diameter) (details given previously in Ref. [54]). After hybridisation, the AuNPs tags were detected by differential pulse voltammetry (DPV). The detection limit was 1.0 x 10-9 mol L 1 of 32-base synthesised complementary oligonucleotide. 

MCPE = magnet carbon paste electrode, SWASV = square wave anodic stripping voltammetry, ASV = anodic stripping voltammetry, PSA = potentiometric stripping analysis, SPEs = screen-printed electrodes, TFGE = thick-film graphite electrode, GCE = glassy carbon electrode. 

The electrochemical study of the in situ interaction of quercetin, adriamycin, DETA/NO and their metabolites with double-stranded DNA (dsDNA) immobilized on a glassy carbon electrode (GCE) surface. 

Sp a, anodic peak potential PtC, cathodic peak potential. Glassy-carbon electrode (GCE) scan rate 0.1 V s-1. 

Figure 10.2 Cyclic voltammograms for (a) 1 mM [Cun(MeCN)4](C104)2 (b, a) plus 3 equiv of bpy (c, a) plus 2 equiv of typ and (d, a) plus 3 equiv of PA in MeCN [0.1 M (E NJCIOJ. Scan rate 0.1 V s l glassy-carbon electrode (GCE) (0.9 cm2) SCE versus NHE, +0.244 V.

The success of the polymerization depends on the solvent used for the process. Most studies of electropolymerized MPc have concentrated on the electrochemical polymerization of MPc(NH2)4 complexes [89-93], The polymerization process of these complexes involves the oxidation of the amino group forming radicals which attack phenyl rings of neighboring molecules [93], The formation of the polymers of (OH)MnPc(NH2)4 and OTiPc(NH2)4 on glassy carbon electrode (GCE) was successfully achieved via electropolymerisation of these complexes in DMF by repetitive scanning at a constant scan rate of 0.1 Vs-1. Simple adsorption of the monomer onto carbon electrodes (using MnPc derivatives) has been reported [94],... 

Acetylcholineesterase and choline oxidase A glassy carbon electrode (GCE) modified by electrodepositing sub pm Pt-black particles on the surface. ACh and Ch. micro biosensor arrays were fabricated based on immobilization of AChE—ChO or ChO by cross linking with gentar-aldehyde on Pt-black GCE. Significant enhancement in the performance of these biosensors was achieved. The chronoamperometric response of 1 p biosensor array was linear from 29 to 1200 pM with detection limit of 8.7 pM acetylcholine. [109]... 

Fig. 5.31. Cyclic voltammograms of PCBM, azafulleroid 5 and ketolactam 6. Experimental conditions were as follows V vs. Ag wire, working electrode GCE, supporting electrolyte Bu4NPF6 (0.1 M), solvent ODCB/MeCN (4/1), scan rate 100 mV/s...

In one case [50] the electrode was prepared by casting a polished and clean glassy carbon electrode GCE with 10 pL of a solution obtained by dispersion of MWCNTs in concentrated sulfuric acid (1 mg/mL) followed by drying at 200 °C for 3h and careful rinsing. 

Cephalexin, cefazolin/human synthetic serum DPV Working electrode GCE Reference electrode Ag/Ag/Cl Supporting electrolyte 0.1 M phosphate buffer solution (pH 3.0) Dissolving in the supporting electrolyte LOD 1 X lO" M LOQ n/a [83]... 

Propranolol, 4 -hydroxypropranolol, 4 -hy droxypropranolol sulfate/urine DPV Working electrode GCE, MWCNT-GCE Reference electrode Ag/Ag/Cl Supporting electrolyte Britton-Robinson buffer (pH 3) Extraction SPE/column Oasis HLB/elution MeOH LOD 1.10-1.37 pmol/L LOQ 3.31. 11 pmol/L [85]... 

Abbreviations GOx-glucose oxidase HRP-horse radish peroxidase PAMAM-poly(arnidoamine) Gn - generation number CPE-carbon paste electrode GCE-glassy carbon electrode ITO-indium-tin oxide CoHCF-cobalt hexacyanoferrate K M - apparent Michaelis-Menten constant LbL-layer-by-layer SAM-self-assembled monolayer... 

ZnO nanoparticles dispersed CH composite films deposited onto glassy carbon electrode (GCE) have been used for immobilization of tyrosinase enzyme for phenol detection. This biosensor shows 95% of steady-state current within 10s, sensitivity as 182 pA mmol"1 L with a detection limit of 5.0 x 10"8 mol/L, exhibits maximum response at 50°C and retains 91% current after about 20 days [39], A sol-gel derived ZnO matrix has been used to immobilize tyrosinase for determination of phenol concentration from 1.5 x 10"7 to 4.0 x 10"5 mol L"1 with detection limit of 8.0 x 10 s mol L"1 and sensitivity of 168 pA mmol L"1. This biosensor shows 95% of steady-state current within 15s after 2 weeks [40], Chen et al. have immobilized mushroom tyrosinase oxidase onto ZnO nanorods for the phenol and catechol detection. The linear concentration ranges have been obtained from 0.02 to 0.1 mM and 0.01 to 0.4 mM, for phenol and catechol, respectively. The apparent Km has been estimated as 0.24 mM for phenol and 1.75 mM for catechol [59],... 

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