Carbon nanotube-loaded Nafion film electrochemical sensor for metal ions: europium.

A Nafion film loaded with novel catalyst-free multiwalled carbon nanotubes (MWCNTs) was used to modify a glassy carbon (GC) electrode to detect trace concentrations of metal ions, with europium ion (Eu(3+)) as a model. The interaction between the sidewalls of MWCNTs and the hydrophobic backbone of Nafion allows the MWCNTs to be dispersed in Nafion, which was then coated as a thin film on the GC electrode surface. The electrochemical response to Eu(3+) was found to be ∼10 times improved by MWCNT concentrations between 0.

The Application of Nafion Metal Catalyst Free Carbon Nanotube Modified Gold Electrode: Voltammetric Zinc Detection in Serum.

Metal catalyst free carbon nanotube (MCFCNT) whiskers were first used as an electrode modification material on a gold electrode surface for zinc voltammetric measurements. A composite film of Nafion and MCFCNT whiskers was applied to a gold electrode surface to form a mechanically stable sensor. The sensor was then used for zinc detection in both acetate buffer solution and extracted bovine serum solution.

Manganese Detection with a Metal Catalyst Free Carbon Nanotube Electrode: Anodic versus Cathodic Stripping Voltammetry.

Anodic stripping voltammetry (ASV) and cathodic stripping voltammetry (CSV) were used to determine Mn concentration using metal catalyst free carbon nanotube (MCFCNT) electrodes and square wave stripping voltammetry (SWSV). The MCFCNTs are synthesized using a Carbo Thermal Carbide Conversion method which results in a material that does not contain residual transition metals. Detection limits of 120 nM and 93 nM were achieved for ASV and CSV, respectively, with a deposition time of 60 s.

Simplified nitrate-reductase-based nitrate detection by a hybrid thin-layer controlled potential coulometry/spectroscopy technique.

A novel method for the detection of nitrate was developed using simplified nitrate reductase (SNaR) that was produced by genetic recombination techniques. The SNaR consists of the fragments of the Mo-molybdopterin (MO-MPT) binding site and nitrate reduction active site and has high activity for nitrate reduction. The method is based on a unique combination of the enzyme-catalyzed reduction of nitrate to nitrite by thin-layer coulometry followed by spectroscopic measurement of the colored product generated from the reaction of nitrite with Griess reagents.

Use of high-purity metal-catalyst-free multiwalled carbon nanotubes to avoid potential experimental misinterpretations.

Carbon nanotubes, even after extensive posttreatment, contain metallic impurities which may produce misleading results, giving rise to false claims of the properties of carbon nanotubes. To overcome this, we report on high-purity catalyst-free multiwalled carbon nanotubes which have been explored with transmission electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry using the electrochemical oxidations of hydrazine and potassium ferrocyanide. The multiwalled carbon nanotubes are approximately 150 nm in length and consist of 6-10 graphite layers.