Zhi-jie Lin

Nonenzymatic amperometric sensing of glucose by using palladium nanoparticles supported on functional carbon nanotubes

A nonenzymatic electrochemical method was developed for glucose detection using an electrode modified with palladium nanoparticles (PdNPs)-functional carbon nanotubes (FCNTs). PdNPs were homogeneously modified on FCNTs through a facile spontaneous redox reaction and characterized by transmission electron microscopy. Based on the voltammetric and amperometric results, PdNPs efficiently catalyzed the oxidation of glucose at 0.40 V in the presence of 0.2M NaCl and showed excellent resistance towards poisoning from such interfering species as ascorbic acid, uric acid, and p-acetamidophenol. This anti-poisoning ability was investigated using analysis of the electrocatalytic products by in situ subtractively normalized interfacial Fourier transform infrared reflection spectroscopy, and the results indicated that no strongly adsorbed CO(ad) species could be found in the oxidation products, which was obviously different from the results obtained using Pt-based electrodes. In order to verify the sensor reliability, it was applied to the determination of glucose in urine samples. The results indicated that the proposed approach provided a highly sensitive, wide linear range, more facile method with good reproducibility for glucose determination, promising the development of Pd-based material in nonenzymatic glucose sensing.

A novel non-enzymatic ECL sensor for glucose using palladium nanoparticles supported on functional carbon nanotubes

A novel non-enzymatic electrochemiluminescence (ECL) sensor based on palladium nanoparticles (PdNPs)-functional carbon nanotubes (FCNTs) was discovered for glucose detection. PdNPs were homogeneously modified on FCNTs using a facile spontaneous redox reaction method. Their morphologies were characterized by transmission electron microscopy (TEM). Based on ECL experimental results, the PdNPs-FCNTs-Nafion film modified electrode displayed high electrocatalytic activity towards the oxidation of glucose. The free radicals generated by the glucose oxidation reacted with the luminol anion (LH(-)), and enhanced the ECL signal. Under the optimized conditions, the linear response of ECL intensity to glucose concentration was valid in the range from 0.5 to 40 micromol L(-1) (r(2)=0.9974) with a detection limit (S/N=3) of 0.09 micromol L(-1). In addition, the modified electrode presented high resistance towards the poisoning of chloride ion, high selectivity and long-term stability. In order to verify the sensor reliability, it was applied to the determination of glucose in glucose injection samples. The results indicated that the proposed approach provided a highly sensitive, more facile method with good reproducibility for glucose determination, promising the development of a non-enzymatic ECL glucose sensor.

A facile synthesis of palladium nanoparticles supported on functional carbon nanotubes and its novel catalysis for ethanol electrooxidation

In this study, a novel material, palladium nanoparticles-carboxylic functional carbon nanotubes (PdNPs-CFCNTs), based on PdNPs supported on CFCNTs was synthesized by a facile spontaneous redox method. The material reveals high electrochemical activity and excellent catalytic characteristic for alcohol electrooxidation on a glassy carbon electrode (GCE) in an alkaline medium. The preparation mechanism was studied by the galvanic cell effect between PdCl(4)(2-) and functional defect sites on CFCNTs. Results from UV-visible absorption spectroscopy and electrochemical impedance spectroscopy revealed that the reduction of PdCl(4)(2-) to metallic Pd was successfully achieved. Morphologies of PdNPs supporting on CFCNTs (PdNPs-CFCNTs) were also characterized by transmission electron micrograph. PdNPs-CFCNTs with the best electrocatalytic characteristics were obtained under the condition as: the weight ratio of Pd to CFCNTs was kept at 2:1, the temperature was kept at 70 degrees C in the synthesis, and the scan rate of the applied potential was selected at 60 mV s(-1). The results indicate that PdNPs-CFCNTs could be a great potential material in direct ethanol fuel cells and ethanol sensors.

Fabrication of a Colorimetric Electrochemiluminescence Sensor

A colorimetric electrochemiluminescence (ECL) sensor was fabricated for the first time, based on a dual-color system including a strong red Ru(bpy)(3)(2+) ECL and a green reference light from a light emitting diode. Traditional ECL intensity information can be easily transformed into a color variation with this sensor, and the color variation can be directly monitored using the naked eye or a commercial CCD camera. The sensor has been successfully used to determine the concentration of tripropylamine, proline (enhancing system), and dopamine (quenching system). The results indicated that the color variation obtained corresponded to the concentration of target analytes. This sensor has potential application in rapid and semiquantitative ECL analysis.

Electrogenerated chemiluminescence ethanol biosensor based on alcohol dehydrogenase functionalized Ru(bpy)32+ doped silica nanoparticles

An ethanol biosensor, based on the electrogenerated chemiluminescence of Ru(bpy)(3)(2+)-doped silica nanoparticles (RuSiNPs), was investigated in this study. The biosensor was a modified glassy carbon electrode, where alcohol dehydrogenase was crosslinked to RuSiNPs, and then immobilized on the electrode surface using chitosan. The results indicated that the biosensor exhibited excellent performance during ethanol determination with a wide linear range (10(-7) to 10(-2) M), low detection limit (5.0x10(-8) M) and good stability.

Electrochemiluminescence detection of dichlorvos pesticide in luminol-CTAB medium

A simple, novel electrochemiluminescence (ECL) method for the detection of dichlorvos pesticide (DDVP) with high sensitivity was discovered. Detection was carried out in a static ECL system, in which a glassy carbon electrode was selected as the working electrode. ECL parameters, including the concentrations of cetyrltrimethylammonium bromide and luminol, the solution pH, and the scan rate of the applied potential, were optimized. Under these optimal conditions, the linear response of ECL-emission versus DDVP concentration was valid in the range 5-8000 ng/L (r(2)=0.9982) with a relative standard deviation of 4.3% at 2000 ng/L (n=10), yielding a detection limit (S/N=3) of 0.42 ng/L. The ECL emission was caused by a radical reaction process, in which the dissolved oxygen in the luminol solution reacted with the DDVP and generated free radicals. The free radicals reacted with the luminol anion and yielded the luminol radical. The approach presented was successfully applied to the determination of DDVP residues in vegetable samples.

Encoding electrochemiluminescence using Ru(bpy)(3)(2+) and fluorescein isothiocyanate co-doped silica nanoparticles

In this paper, an electrochemiluminescence (ECL) encoding method was developed for the first time, based on a dual-dye system including Ru(bpy)(3)(2+) as an ECL emitter and fluorescein isothiocyanate (FITC) as a coding dye.

Electrochemiluminescence of 9,10-diphenylanthracene doped polystyrene beads in aqueous media

In order to use a water soluble organic electrochemiluminescence (ECL) reagent in an aqueous medium, a simple one-pot method was developed to synthesize 9,10-diphenylanthracene (9,10-DPA) doped polystyrene beads based on dispersion polymerization. The bead size was around 3 μm and they were well dispersed. Fluorescence experiments showed that the polystyrene beads were successfully doped in 9,10-DPA. The 9,10-DPA doped beads were then used in ECL studies, and they retained their ECL activity well. The results imply that polystyrene beads could be a suitable platform leading to the application of hydrophobic ECL reagents in aqueous media.