Direct Ascorbic Acid detection with ferritin immobilized on single-walled carbon nanotubes

Ferritin protein was noncovalently immobilized onto single-walled carbon nanotubes (SWNTs). This SWNT/ferritin composite was characterized using cyclic voltammetry, UV-visible spectroscopy, Raman spectroscopy, and high-resolution transmission electron microscopy. The use of the SWNT/ferritin film as an amperometric biosensor was demonstrated by sensing ascorbic acid in phosphate-buffered saline solution with a sensitivity of 767 uAmg. It demonstrated that ferritin protein bound to SWNTs enhances the oxidation reaction of ascorbic acid over 11-fold

An Environmentally Friendly Compact Microfluidic Hydrodynamic Sequential Injection System Using Curcuma putii Maknoi & Jenjitt. Extract as a Natural Reagent for Colorimetric Determination of Total Iron in Water Samples

The miniaturization of analytical systems and the utilization of nontoxic natural extract from plants play significant roles for green analytical chemistry methodology. In this work, the microfluidic hydrodynamic sequential injection (HSI) with the LED-phototransistor colorimetric detection system has been proposed to create an ecofriendly and low-cost miniaturized analytical system for online determination of iron in water samples using Curcuma putii Maknoi & Jenjitt. extracts as high stability and good selectivity of a natural reagent. The proposed method was designed for online solution mixing and colorimetric detection on a microfluidic platform. The Curcuma putii Maknoi & Jenjitt. extracts and standard/samples were sequentially aspirated to fill the channel before entering the built-in flow cell. The intensity of iron-Curcuma putii Maknoi & Jenjitt. extract complex was monitored under the optimum conditions of flow rate, sample volume, mixing zone length, and aspiration sequences, by altering the gain control of the colorimetric detector to achieve good sensitivity. The results demonstrated a good performance of the green analytical systems. A linear calibration graph in the range of 0.5–6.0 mg L−1 was obtained with a limit of detection at an adequate level of 0.11 mg L−1 for water samples with a sample throughput of 30 h−1. The precise and accurate measurement results were achieved with relative standard deviations in the range of 1.61–1.72%, and percent recoveries were found in the range of 90.6–113.4. The proposed method offers cost-effective, easy operation over an appropriate analysis time (2 min/injection) with good sensitivity and is environmentally friendly with low consumption of solutions and the use of high stability and good selectivity of nontoxic reagents. The achieved method was demonstrated to be a good choice for routine analysis

Folia ethnographica : supplementum ad Acta Musei Moraviae, Scientiae sociales

Titanium dioxide/single-walled carbon nanotube TiO2/SWNT composites were prepared for photocatalytic applications. Thecomposites were characterized using UV-visible and Raman spectroscopy, zeta-potential measurements, cyclic voltammetrycoupled with a photoreactor, scanning electron microscopy, and transmission electron microscopy coupled with energy dispersiveX-ray spectroscopy. The photocatalytic activity of TiO2 and the TiO2/SWNT composite was investigated using the photo-oxidationof methanol in sulfuric acid as supporting electrolyte. The results indicate that the TiO2/SWNT composite enhances the photocatalyticactivity compared to TiO2 alone. Electrochemical studies of the TiO2/SWNT composite were also carried out in varioussupporting electrolytes and the presence of SWNTs was shown to increase the current achieved in voltammetric measurements

Direct growth of carbon nanotubes onto titanium dioxide nanoparticles.

Multi-wall carbon nanotubes (MWNTs) were successfully deposited on a TiO2 nanoparticle film via thermal chemical vapour deposition (CVD) using iron(III) as the catalyst, which was loaded into the titanium isopropoxide precursor solution. The properties of the TiO2/MWNTs nanocomposite was characterized using Raman spectroscopy, scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), 4-point probe conductivity measurements and cyclic voltammetry. Preliminary investigations on this TiO2/MWNTs nanocomposite as an anode material for Li-ion batteries shows a high reversible capacity of 268 mAh g(-1) with improved cycling stability compared with a mechanically blended composite