Yi-Min Fang

Catalytic electrogenerated chemiluminescence and nitrate reduction at CdS nanotubes modified glassy carbon electrode.

Electrochemical and electrogenerated chemiluminescence (ECL) properties of a glassy carbon electrode modified with CdS nanotubes (CdS-GCE) are investigated in neutral media. The cyclic voltammogram (CV) shows two cathodic peaks (P(C1) and P(C2)) at -0.76 and -0.97 V and an anodic peak (P(A)) at -0.8 V, while two ECL peaks around -0.76 V are observed. Similar mechanisms of both ECLs are supposed and possibly related to the capture of an electron at a surface trap, that is, the surface sulfide vacancy (V(S)(2+)) of CdS nanotubes and its electrocatalytic reduction to H(2)O(2) generated from the dissolved oxygen. P(C2) and P(A) are ascribed to the two-electron redox at V(S)(2+). Moreover, electrocatalysis to nitrate reduction is also found at P(C2), with a good linear relationship between nitrate concentration and electrocatalytic peak current in CV.

Gold nanoparticles for highly sensitive and selective copper ions sensing—old materials with new tricks

We report a new application of gold nanoparticles for visual detection of copper ions with high sensitivity and selectivity based on the colorimetric difference due to the strong and specific inhibition of Cu(NH3)62+ to the corrosion of gold nanoparticles at low concentration.

Facile Electrochemical Preparation of Ag Nanothorns and Their Growth Mechanism

National Science Foundation of China [20775015, 211735002, 20975022]; National Basic Research Program of China [2010CB732403]; MOE [20070386005]; NCETTFJ [XSRC2007-02]; State Key Laboratory of Physical Chemistry of Solid Surfaces of Xiamen University

An extremely stable and sensitive end-column electrochemical detector based on heated copper microdisk electrode with direct current for CE and CE-Chip

A heated copper microdisk electrode (HCME) was fabricated and successfully applied to capillary electrophoresis (CE) and CE-Chip as an electrochemical detector (ECD) for the detection of three carbohydrates and shikimic acid (SA) in Illicium verum Hook F., respectively. The temperature of HCME was heated by twin-wire-wound coil with direct current to reduce the magnetic interference. Coupled with CE and CE-chip, this detector exhibits both extremely stable and sensitive performance at elevated temperature compared with that at room temperature. In successive detection of three carbohydrates and shikimic acid (SA), the HCME exhibits very stable response with RSD of ca. 2% with elevated temperature without renewing the electrode, while at room temperature, RSD of ca. 20% is obtained. This is very important in practical applications that tedious works, such as polishing and re-fixing the electrode at each detection, can be therefore avoided. In addition, the sensitivity is about 2-6 time increased, and the linear range is about an order wider at elevated temperature (ca. 60 degrees C) than that at room temperature (ca. 25 degrees C).

Study on the electrochemical catalytic properties of the topological insulator Bi2Se3

In this work, the electrochemical catalytic properties of the topological insulator bismuth selenide (Bi₂Se₃) were first studied. In the presence of Bi₂Se₃ the reduction current of dissolved O₂ could be significantly enhanced. The electron transfer resistivity (Rct) was greatly reduced at the Bi₂Se₃-PVP modified electrode as evidenced by the electrochemical impedance spectrometry, implying that the topological insulator Bi₂Se₃ could facilitate the electron transfer at the interface due to the excellent surface conductivity. Based on the high electrochemical catalytic activity for the reduction of dissolved O₂, the Bi₂Se₃-PVP modified electrode was used to detect glucose with the modification of glucose oxidase, and applied for the detection of glucose in human blood serum.

A Simple Approach to the Solution of the Diffusion Equation at the Microcylinder Electrode—an Inspiration from the Film Projector

Electrochemistry at microelectrodes has attracted great attention since the 1980s because of their unique features, such as a rapid mass transfer rate, reduced iR drop and fast electrochemical response. In the family of microelectrodes, the microcylinder, for example the carbon fiber electrode, is one of the favorites that is frequently used in in vivo measurements due to its wide potential range and high biocompatibility. Recently, microcylinder electrodes, such as Pt wires, Au wires and graphite cylinders, used as heated electrodes, are also well developed as a highly sensitive analytical method. Since the diffusion equation is similar to that in heat conduction, the mathematical solution to cylindrical diffusion has been established by employing it in the field of heat transfer by Jaeger, 16] and it has been applied to some electrochemical techniques, such as chronoamperometry and linear sweep voltammetry. However, the solving processes of the diffusion equations, that is, the partial differential equations, are relatively complicated. The chronoamperometric current is given by Equations (1) and (2):

Electrodeposition of bright gold—a green path using hypoxanthine as a complexing agent

A simple, low cost, stable and environmentally friendly gold plating electrolyte containing hypoxanthine as a complexing agent is introduced. Bright and compact gold deposits could be obtained by using PEI-1800 and SUNO (a compound that contains the element sulfur) as additives for electrodepositing gold on a nickel substrate.

Hot electron induced cathodic electrochemiluminescence at AuSb alloy electrode for fabricating immunosensor with self-assembled monolayers

Thin antimony oxide covered AuSb alloy electrode was firstly found to be an excellent cold cathode for generating hot electrons during cathodic pulse polarization. Owing to the injection of hot electrons and the subsequent generation of hydrated electrons, fluorescein iso-thiocyanate (FITC) that cannot be excited in common ECL was cathodically excited at the alloy electrode. Self-assembled thiol monolayers were formed on the electrode surface due to the presence of Au in the alloy, to which strepavidin was covalently bound, and then biotinylated antibody was immobilized through the strepavidin-biotin interaction. As a simple model, an immunosensor for the detection of human IgG (hIgG) using FITC as labeling agent was fabricated. ECL signals were responsive to the amount of hIgG bounded to the immunosensor. The ECL intensity was linearly changed with the logarithm of hIgG concentration in the range of 1.0-1000 ng mL(-1), and the detection limit was ca. 0.3 ng mL(-1) (S/N=3). The proposed immunosensor showed a broad linear range (three magnitudes), good reproducibility and stability, which is promising in detecting FITC-based labels in various types of bioaffinity assays.

Electrogenerated chemiluminescence emission from cadmium germanate nanoparticles

The ECL phenomenon of nano Cd2Ge2O6, both amorphous and crystallized, is described in this paper. This is the first report on the ECL of semiconductor nanocrystals involving three elements and also the first paper dealing with the amorphous nanomaterials, which shed some light on the exploration of new ECL nanomaterials. The ECL mechanism could be ascribed to the cadmium-rich surface state of amorphous Cd2Ge2O6. The ECL intensity linearly increased along with the square of the H2O2 concentration. Therefore, it was employed to detect hydrogen peroxide, and the linear range was 5.0 × 10−6 to 4.0 × 10−4 mol L−1.