Electrochemical detection of hydrogen peroxide using an edge-plane pyrolytic-graphite electrode (EPPG), a glassy carbon (GC) electrode, and a silver nanoparticle-modified GC electrode is reported. It is shown, in phosphate buffer (0.05 mol L(-1), pH 7.4), that hydrogen peroxide cannot be detected directly on either the EPPG or GC electrodes. However, reduction can be facilitated by modification of the glassy-carbon surface with nanosized silver assemblies. The optimum conditions for modification of the GC electrode with silver nanoparticles were found to be deposition for 1 min at -0.5 V vs. Ag from 5 mmol L(-1) AgNO3/0.1 mol L(-1) TBAP/MeCN, followed by stripping for 2 min at +0.5 V vs. Ag in the same solution. A wave, due to the reduction of hydrogen peroxide on the silver nanoparticles is observed at -0.68 V vs. SCE. The limit of detection for this modified nanosilver electrode was 2.0 x 10(-6) mol L(-1) for hydrogen peroxide in phosphate buffer (0.05 mol L(-1), pH 7.4) with a sensitivity which is five times higher than that observed at a silver macro-electrode. Also observed is a shoulder on the voltammetric wave corresponding to the reduction of oxygen, which is produced by silver-catalysed chemical decomposition of hydrogen peroxide to water and oxygen then oxygen reduction at the surface of the glassy-carbon electrode.

Silver nanoparticle assemblies supported on glassy-carbon electrodes for the electro-analytical detection of hydrogen peroxide.

Enzyme microsensor for glucose with an electrochemically synthesized enzyme-polyaniline film

A method for estimation of hydrogen peroxide based on mediated electron transfer reactions of peroxidases at electrodes

The term “biosensor” has become a fashionable buzzword in recent analytical literature. While scientists have used the word to describe any number of innovative devices and instrumental systems, we believe that the two most widely accepted definitions are as follows:

Recent advances in the development and analytical applications of biosensing probes

Gold nanoparticles (GNPs) were electrochemically deposited on the graphene and chitosan modified glassy carbon electrode and characterized by scanning electron microscope and cyclic voltammetry, respectively. A simple non-enzymatic H 2 O 2 sensor was developed based on the direct electrochemistry of H 2 O 2 in the presence of GNPs. Under the optimized conditions, the fabricated electrode displayed a linear response in the H 2 O 2 concentration range from 5.0 μM to 35 mM with a detection limit of 1.6 μM estimated at a signal-to-noise ratio of 3. The proposed sensor presented some advantages including simple operation procedure, wide linear range, low detection limit, fast response time as well as good anti-interference performance, stability and reproducibility, which indicate it can act as a promising electrochemical platform for H 2 O 2 detection.

A simple non-enzymatic hydrogen peroxide sensor using gold nanoparticles-graphene-chitosan modified electrode

A novel biosensor, biophotodiode, is proposed for the determination of substances of biochemical and clinical importance. The biophotodiode is a unique combination of a photodiode and matrix-bound peroxidase. Since the enzyme catalyzes the luminescent reaction of the luminol-H2O2 system, this assembly is effective on the determination of hydrogen peroxide. The photocurrent of the sensor is correlated with the hydrogen peroxide concentration ranging from 1mM to 10 mM. A biophotodiode for glucose is also constructed by assembling a glucose oxidase-peroxidase bienzyme membrane and a photodiode.

M. Aizawa

Papers

Photovoltaic Determination of Hydrogen Peroxide with A Biophotodiode