Gold Nanoparticles Modified Indium Tin Research Articles

L-Cysteine self-assembled Au(1 1 1)-like nanoparticles modified indium tin oxide electrode for determination of dopamine in the present of uric acid

A novel L-Cysteine self-assembled gold nanoparticles modified indium tin oxide electrode (ITO/Au/L-Cys) was fabricated by facile steps of electro-deposition and immersion in solution. The as-prepared ITO/Au/L-Cys electrode is investigated as a potential electrochemical sensor for dopamine (DA) in the interference of Uric Acid (UA). It combines the catalytic advantages of the Au(111)-like nanoparticles array with self-assembled L-Cysteine. The biosensor displays a highly sensitive and selective behavior for DA in the present of UA. The peak currents response to DA is linear with their concentrations in the range of 2 μM ∼ 400 μM. In addition, a limit of detection reaches up to 0.6 μM (S/N = 3). Consequently, the high sensitivity, stability and excellent biocompatibility of ITO/Au/L-Cys electrode made it as a promising DA sensor.

Rapid detection of carbamate pesticide residues using microchip electrophoresis combining amperometric detection

The long-term consumption of food with pesticide residues has harmful effects on human health and the demand for pesticide detection technology tends to be miniaturized and instant. To this end, we demonstrated the first application of indirectly detecting two carbamate pesticides, metolcarb and carbaryl, by gold nanoparticle-modified indium tin oxide electrode in dual-channel microchip electrophoresis and amperometric detection (ME-AD) system. m-Cresol and α-naphthol were obtained after pesticide hydrolysis in alkaline solution, and then separated and detected by ME-AD. Parameters including the detection potential and running buffer concentration and pH were optimized to improve the detection sensitivity and separation efficiency. Under the optimal conditions, the two analytes were completely separated within 80s. m-Cresol and α-naphthol presented a wide linear range from 1 to 100μM, with limits of detection of 0.16μM and 0.34μM, respectively (S/N = 3). Moreover, the reliability of this system was demonstrated by analyzing metolcarb and carbaryl in spiked vegetable samples.

Electrochemical detection of Hg(II) ions based on nanoporous gold nanoparticles modified indium tin oxide electrode

Nanoporous gold nanoparticles (np-Au NPs), dispersed on the indium tin oxide film coated glass, were firstly employed to fabricate Hg(II) sensing platform in differential pulse anodic stripping voltammetry (DPASV). The np-Au NPs integrated the features of highly porous nanoparticles and the high affinity of gold nanomaterials for mercury, which endowed the sensing platform with high sensitivity and good reproducibility. Following optimization of the method, a calibration curve from 0.1 to 10μg/L Hg(II) was obtained in HCl solution. The detection limit was 0.03μg/L (0.15nM) at a signal-to noise ratio of 3. The interference from other heavy metal ions associated with Hg(II) detection could be effectively avoided. The performance of the proposed electrode was also applied in the detection of trace Hg(II) in different real samples with satisfactory results.

Progress in Fabrication and Application of Gold Nanoparticles Modified Indium Tin Oxide Glass

Gold nanoparticles coated on indium tin oxide substrate have been attracting great attention due to their excellent optical, electronic, electrocatalytic and biosensing application in recent years. In this paper, recent research progress in the preparation methods of gold nanoparticles on indium tin oxide substrate surface such as assembling with polymer, seed-mediated growth method and electrodeposition are presented. The applications of gold nanoparticles modified indium tin oxide substrate are also reviewed in electrode, catalyst, sensors and biochemical analysis.

A seed-mediated growth process for the fabrication of a novel gold nanoparticles-attached NH2+ ions implantation-modified indium tin oxide electrode and its electrocatalytic activity

A new type of gold nanoparticles-attached NH2+ ions implantation-modified indium tin oxide electrode (AuNPs/NH2/ITO) was fabricated with a seed-mediated growth method. Amino ion implantation was performed at the energy of 80keV with fluence of 2×1016ionscm−2 for ITO film coated glass, forming the electrode NH2/ITO. The existence of amino groups on the electrode was verified by Fourier transform infrared (FT-IR) spectrometry and X-ray photoelectron spectra (XPS). The attachment of AuNPs onto the surface of the NH2/ITO electrode was exhibited by using the scanning electron microscopy (SEM). Comparing with the gold nanoparticles modified indium tin oxide (AuNPs/ITO), we found that ion implantation approach provided a useful strategy to attach AuNPs on the NH2/ITO surface with higher density. Cyclic voltammetric results indicated that the AuNPs/NH2/ITO electrode showed excellent electrochemical properties and electrocatalytic effects toward some small biomolecules such as uric acid. The current response was increased linearly with increasing uric acid concentration in the range of 1.6×10−5M to 2.6×10−4M and the detection limit was found to be 4.8×10−6M (S/N=3). Thus this material is expected to have widely potential applications in electrochemical analysis and biosensors.

Direct electrochemistry and electrocatalysis of hemoglobin on a gold ion implantation-modified indium tin oxide electrode

In this paper, a gold nanoparticle-modified indium tin oxide electrode (Au/ITO) was prepared without the use of any cross-linker or stabilizer reagent. The prepared Au/ITO was used as a new platform to achieve the direct electron transfer between Hb and the modified electrode. The proposed electrode exhibited a pair of well-defined redox peaks with a formal potential of −0.073 V (vs. Ag/AgCl). The immobilized Hb showed excellent electrocatalytic activity toward H2O2 and the electrocatalytic current values were linear with the increasing concentration of H2O2 ranging from 1.0 × 10−6 M to 7.0 × 10−4 M. The detection limit was 2.0 × 10−7 M (S/N = 3) and the Michaelis–Menten constant was calculated to be 0.2 mM. The proposed electrode also showed high selectivity, long-term stability, and good reproducibility.

Electrochromic properties of WO3 thin film onto gold nanoparticles modified indium tin oxide electrodes

Gold nanoparticles (GNPs) thin films, electrochemically deposited from hydrogen tetrachloroaurate onto transparent indium tin oxide (ITO) thin film coated glass, have different color prepared by variation of the deposition condition. The color of GNP film can vary from pale red to blue due to different particle size and their interaction. The characteristic of GNPs modified ITO electrodes was studied by UV–vis spectroscopy, scanning electron microscope (SEM) images and cyclic voltammetry. WO3 thin films were fabricated by sol–gel method onto the surface of GNPs modified electrode to form the WO3/GNPs composite films. The electrochromic properties of WO3/GNPs composite modified ITO electrode were investigated by UV–vis spectroscopy and cyclic voltammetry. It was found that the electrochromic performance of WO3/GNPs composite films was improved in comparison with a single component system of WO3.

Lack of nano size effect on electrochemistry of dopamine at a gold nanoparticle modified indium tin oxide electrode

Nanometer sized materials have been shown to possess excellent chemical and electrochemical catalytic properties. In this work, a gold nanoparticle (AuNP) modified indium tin oxide (ITO) electrode was employed for investigating its electro-catalytic property. AuNP was deposited on the 3-aminopropyltriethoxysilane (APTES) modified ITO electrode by self-assembly, and was characterized by scanning electron microscopy and cyclic voltammetry. Although the electrochemical reaction of dopamine was very sluggish on the ITO/APTES electrode, it was significantly enhanced after AuNP deposition. The cyclic voltammogram exhibited apparent dependence on the surface coverage of 11 nm AuNPs, which could be rationalized by different modes of mass diffusion. Among the different sizes of AuNP investigated, the lowest anodic peak potential was observed on 11 nm AuNP. However, the potential was still about 50 mV more positive than that obtained on a bulk gold electrode of similar geometry. It is therefore concluded that there is no nanometer size effect of AuNP modified ITO on the electrochemistry of dopamine.

Fullerene C 60 modified gold electrode and nanogold modified indium tin oxide electrode for prednisolone determination

The electrochemical determination of prednisolone has been investigated at fullerene-C 60-modified gold (C 60/Au) electrode and gold nanoparticles modified indium tin oxide (nano Au/ITO) electrode in phosphate buffer solution (PBS) of pH 7.2. During oxidation of prednisolone, an anodic peak with peak potential ( E p) at 570 mV and 400 mV appeared at nano Au/ITO and C 60/Au electrode, respectively. The experimental results revealed that gold nanoparticles as well as fullerene (C 60) promote the rate of prednisolone oxidation by increasing the peak current ( i p) and oxidizing at lower peak potentials as compared to the respective bare electrodes due to their electrocatalytic effect. The linear concentration range at both the electrodes was in the range of 1 μM to 0.10 mM. The detection limit obtained at C 60/Au electrode was 26 nM, while at nano Au/ITO electrode the detection limit was 90 nM. The applicability of the method to direct assays of human urine and whole blood sample is described to use the method for testing cases of doping by athletes.

Sensors for 5-hydroxytryptamine and 5-hydroxyindole acetic acid based on nanomaterial modified electrodes

Abstract Simultaneous voltammetric determination of serotonin and 5-hydroxyindole acetic acid has been described at single walled carbon nanotube modified glassy carbon electrode and gold nanoparticles modified indium tin oxide electrode. The method described is fast, simple, accurate with detection limits as low as 32 nM for 5-hydroxytryptamine (5-HT) at single-walled carbon nanotube modified glassy carbon electrode and 27 nM for 5-hydroxyindole acetic acid (5-HIAA) at gold nanoparticles modified indium tin oxide electrode. Linear variation of peak current with change in concentration was observed in the concentration range 0.1–100 μM for 5-HT and 5-HIAA. Application of the method for non-invasive determination of the compounds in urine samples has also been described. The inter- and intra-day stability of the electrodes were also determined and electrodes were found to be sufficiently stable for 1 week.

Electrochemical Behavior and Application of Pirarubicin at Gold Nanoparticles–Modified Indium Tin Oxide Electrode

A new type of gold nanoparticles–attached indium tin oxide electrode was made. By SEM and EDS, the as‐prepared gold nanoparticles–modified ITO electrode was characterized. This modified electrode has been used for the determination of pirarubicin (THP) in urine by cyclic voltammetry. Compared to a bare ITO electrode, the modified electrode exhibited a marked enhancement in the current response. Liner calibration curves are obtained in the range 5×10−9mol/L∼1.5×10−6 mol/L with a detection limit of 1×10−9 mol/L. The percentage of the recoveries ranged from 99.3% to 106.3%. The practical analytic utility of the method is illustrated by quantitative determination of THP in urine.

Determination of methylprednisolone acetate in biological fluids at gold nanoparticles modified ITO electrode

The electrochemical behavior of a corticosteroid methylprednisolone (MP), used for doping, has been studied at gold nanoparticles modified indium tin oxide (nanoAu/ITO) electrode. The nanoAu/ITO electrode exhibited an effective catalytic response towards its oxidation and lowered its oxidation potential by ∼127 mV when compared with bare ITO electrode. Oxidation of MP has been carried out in phosphate containing electrolyte in the pH range 2.13–10.00 and a well-defined oxidation peak was noticed. Linear concentration curves are obtained over the concentration range 0.01–1.0 μM with a detection limit of 2.68 × 10 −7 M at nanoAu/ITO electrode. A diffusion coefficient of 2.36 × 10 −6 cm 2/s is calculated for MP using chronoamperometry. The proposed method is effectively applied to detect the concentration of MP in pharmaceutical formulations and human blood plasma and urine samples. A comparison of MP concentration determined in blood plasma and urine by the proposed method and GC/MS indicated that the results are essentially similar. It is believed that the method will be useful in determining this drug in case of doping.

Gold nanoparticles modified indium tin oxide electrode for the simultaneous determination of dopamine and serotonin: Application in pharmaceutical formulations and biological fluids

A new rapid, convenient and sensitive electrochemical method based on a gold nanoparticles modified ITO (Au/ITO) electrode is described for the detection of dopamine and serotonin in the presence of a high concentration of ascorbic acid. The electrocatalytic response was evaluated by differential pulse voltammetry (DPV) and the modified electrode exhibited good electrocatalytic properties towards dopamine and serotonin oxidation with a peak potential of 70 mV and 240 mV lower than that at the bare ITO electrode, respectively. The selective sensing of dopamine is further improved by applying square wave voltammetry (SWV) which leads to the lowering of its detection limit. A similar effect on the detection limit of serotonin was observed on using SWV. Linear calibration curves are obtained in the range 1.0 × 10 −9–5.0 × 10 −4 M and 1.0 × 10 −8–2.5 × 10 −4 M with a detection limit of 0.5 nM and 3.0 nM for dopamine and serotonin, respectively. The Au/ITO electrode efficiently determines both the biomolecules simultaneously, even in the presence of a large excess of ascorbic acid. The adequacy of the developed method was evaluated by applying it to the determination of the content of dopamine in dopamine hydrochloride injections. The proposed procedure was also successfully applied to simultaneously detect dopamine and serotonin in human serum and urine.

Voltammetric determination of anabolic steroid nandrolone at gold nanoparticles modified ITO electrode in biological fluids

The electrochemical behavior of nandrolone decanoate (ND) at gold nanoparticles modified indium tin oxide (ITO) electrode was investigated. Oxidation of ND has been carried out in phosphate containing supporting electrolyte in the pH range 2.1–9.2 and a well-defined oxidation peak was noticed. The peak potential ( E p) of the oxidation peak decreases linearly with increasing pH. Linear calibration curve is obtained over the nandrolone decanoate concentration range of 50 nM to 1.5 μM at pH 7.2 with a detection limit of 1.36 × 10 −7 M. The proposed method is effectively applied to detect the concentration of ND in human blood serum and urine samples after 24 and 72 h of intramuscular injection. The method is rapid and does not require any pre-treatment.

Simultaneous determination of guanosine and guanosine-5′-triphosphate in biological sample using gold nanoparticles modified indium tin oxide electrode

A nanogold modified indium tin oxide (ITO) electrode was used for the simultaneous determination of guanosine and GTP at pH 7.2. The electrode exhibited an effective catalytic response towards their oxidation and lowered the oxidation potential of guanosine by ∼120 mV and GTP by ∼183 mV. Linear concentration curves were obtained for guanosine with a detection limit of 9.8 × 10 −8 M and 5.5 × 10 −8 M for GTP. The concentration of guanosine and GTP were also estimated in the human blood plasma samples using gold nanoparticles modified ITO electrode with good reproducibility.

Direct Electrodeposition of Gold Nanoparticles onto Indium Tin Oxide Film Coated Glass: Application to the Detection of Arsenic(III)

Gold nanoparticle modified indium tin oxide (ITO) film coated glass electrodes were prepared for the first time through direct electrochemical deposition from 0.5 M H2SO4 containing 0.1 mM HAuCl4. The resulting electrode surfaces were characterized with AFM. Cyclic voltammetry and linear sweep voltammetry (LSV) of arsenic(III) on the modified electrodes were performed. After optimization, a LOD of 5 +/- 0.2 ppb was obtained with 60 s deposition at -0.6 V (vs. SCE) in 1 M HNO3 using LSV.

Differential pulse voltammetric determination of atenolol in pharmaceutical formulations and urine using nanogold modified indium tin oxide electrode

A gold nanoparticles modified indium tin oxide (ITO) electrode has been used for the determination of atenolol (ATN) in drug formulations and urine by differential pulse voltammetry (DPV). Compared to a bare ITO electrode, the nanogold modified electrode exhibited an apparent shift of the oxidation potential in the less positive direction and a marked enhancement in the current response for ATN. Linear calibration curve was obtained in the range 0.5 μM to 1.0 mM in 1.0 M phosphate buffer solution (pH 7.2) with a correlation coefficient of 0.9965. The detection limit of atenolol in the standard solution (pH 7.2) is estimated to be 0.13 μM. The percentage recoveries ranged from 95.7% to 105.2%. The practical analytical utility of the method is illustrated by quantitative determination of ATN in several commercially available pharmaceutical formulations and urine, without any preliminary treatment.