Tin Oxide Coated Glass Electrode Research Articles

Towards Molecularly Imprinted Polypyrrole-Based Sensor for the Detection of Methylene Blue

This study is dedicated to molecularly imprinted polymer-based sensor development for methylene blue detection. The sensor was designed by molecular imprinting of polypyrrole with phenothiazine derivative methylene blue (MB) as a template molecule. The molecularly imprinted polymer (MIP) was deposited directly on the surface of the indium tin oxide-coated glass electrode by potential cycling. Different deposition conditions, the layer’s durability, and thickness impact were analysed. The working electrodes were coated with molecularly imprinted and non-imprinted polymer layers. Potential pulse chronoamperometry and cyclic voltammetry were used to study these layers. Scanning electron microscopy was used to determine the surface morphology of the polymer layers. The change in optical absorption was used as an analytical tool to evaluate the capability of the MIP layer to adsorb MB. Selectivity was monitored by tracking the optical absorption changes in the presence of Azure A. In the case of MB adsorption, linearity was observed at all evaluated calibration plots in the concentration range from 0.1 μM to 10 mM. The novelty of this article is based on the methodology in the fabrication process of the sensors for MB, where MB retains its native (non-polymerised) form during the deposition of the MIP composite.

Investigation of Peptides for Molecular Recognition of C-Reactive Protein-Theoretical and Experimental Studies.

We investigate the interactions between C-reactive protein (CRP) and new CRP-binding peptide materials using experimental (biological and physicochemical) methods with the support of theoretical simulations (computational modeling analysis). Three specific CRP-binding peptides (P2, P3, and P9) derived from an M13 bacteriophage have been identified using phage-display technology. The binding efficiency of the peptides exposed on phages toward the CRP protein was demonstrated via biological methods. Fibers of the selected phages/peptides interact differently due to different compositions of amino acid sequences on the exposed peptides, which was confirmed by transmission electron microscopy. Numerical and experimental studies consistently showed that the P3 peptide is the best CRP binder. A combination of theoretical and experimental methods demonstrates that identifying the best binder can be performed simply, cheaply, and fast. Such an approach has not been reported previously for peptide screening and demonstrates a new trend in science where calculations can replace or support laborious experimental techniques. Finally, the best CRP binder─the P3 peptide─was used for CRP recognition on silicate-modified indium tin oxide-coated glass electrodes. The obtained electrodes exhibit a wide range of operation (1.0-100 μg mL-1) with a detection limit (LOD = 3σ/S) of 0.34 μg mL-1. Moreover, the dissociation constant Kd of 4.2 ± 0.144 μg mL-1 (35 ± 1.2 nM) was evaluated from the change in the current. The selectivity of the obtained electrode was demonstrated in the presence of three interfering proteins. These results prove that the presented P3 peptide is a potential candidate as a receptor for CRP, which can replace specific antibodies.

Fabrication of Au nano particles/Fluorine doped Tin Oxide coated glass electrodes via electrophoretic deposition for high-sensitive arsenic (III) detection

Nowadays, one of global environment issues is arsenic pollution. Consequently, developing the effective detection techniques to detect the levels of arsenic-contamination in various mediums is necessary. This work aimed to fabricate the gold nano particles/Fluorine doped Tin Oxide coated glass (FTO) electrode using the electrophoretic technique for highly sensitive As(III) detection . The gold nanoparticles (AuNPs) that synthesized from HAuCl4 via ascorbic acid as a reducing agent, were electrophoretically deposited on FTO electrodes at 3 V; UV-Vis spectroscopy of AuNPs/FTO electrodes showed the characteristic peak of AuNPs at 530.5-539.5 nm, that confirmed the deposition of AuNPs on FTO. The field emission scanning electron microscope images illustrated the uniform AuNPs on the surface of the electrodes in the range of 25-40 nm. The linear sweep voltammetry and cyclic voltammetry curves confirmed that the superior electrochemical performance was belonged to AuNPs/FTO electrodes preparing at 3 V for 120 minutes. The AuNPs/FTO electrodes were employed for As(III) detection using anodic stripping voltammetry technique and exhibited a linear responses (R2 = 0.98) in the range of 1-50 ppb with limit of detection of 0.81 ppb As(III). Our work confirmed that an electrophoretic deposition of nanomaterials as a simple and promising technique to prepare working electrodes for various electrochemical analyses.

A Microporous Bifunctional Electrochromic Energy‐Storage Polymer of Thiophene, Triphenylamine, and Thienothiophene

The novel monomer, 4‐(2‐(4‐(bis(4‐(thiophen‐2‐yl)phenyl)amino)phenyl)‐5‐(thiophen‐2‐yl)thieno[3,2‐b]thiophen‐3‐yl)benzonitrile, is synthesized by applying Suzuki coupling reaction and electropolymerized directly onto indium tin oxide coated glass electrode surface to obtain a conjugated microporous polymer of [Th3CNTT–TPA] (P[Th3CNTT–TPA]). The morphology and structure of the polymer film are characterized by atomic force microscopy, Fourier transform infrared, and UV–visible spectroscopies. Electrochemical properties are studied using cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic charge–discharge, and chronoamperometric measurements. Its gravimetric capacity and capacitance values are measured to be 65 and 235 F g−1 at a current density of 3 A g−1, respectively. It shows high energy and power densities of 65 and 32.5 kWh kg−1, respectively, and exhibits high coloration efficiency of 513 C−1 cm2 in visible region, switching between yellow and grey colors. Three different electrochromic–supercapacitor devices, that is, one symmetrical (energy storage device (ESD)1) and two asymmetrical, using poly(3,4‐ethylendioxythiophen) (ESD2) and poly(3,4‐propylenedioxypyrrole) (ESD3) as counter electrodes, are fabricated. The asymmetrical device, ESD3, demonstrats better capacity and stability. Regarding the cyclic stability and electrochromic‐energy‐storage properties, P[Th3CNTT–TPA] can be considered as a good candidate for multifunctional applications.

Fabrication of a label-free electrochemical cell-based biosensor for toxicity assessment of thiram

Thiram has been widely used in agriculture and may invades the food chain, posing a threat to human health. In this research, a label-free electrochemical cell-based biosensor was presented for in vitro toxicity assessment of thiram. HepG2 cells were cultured on poly-l-lysine@gold nano-flowers functionalized indium tin oxide coated glass electrode (PLL@AuNFs/ITO) to serve as biorecognition elements. AuNFs were electrodeposited on ITO to provide an enlarged specific surface area and benefited the output signal amplification. PLL was selected as an effective biocompatible coating material to facilitate cell adhesion and proliferation, thereby realizing one-step recording of electrochemical signals from thiram-treated cells. With the aid of the differential pulse voltammetry method, the fabricated biosensor was applied to assess the cytotoxicity of thiram. Results showed that the cytotoxicity measured by the fabricated biosensor exhibited a linear relationship related to thiram concentration ranging from 5 to 50 μM with a detection limit of 2.23 μM. The IC50 of thiram obtained by the biosensor was 29.5 μM, which was close to that of conventional MTT assay (30.8 μM). The effects of thiram on HepG2 cells were also investigated via SEM and flow cytometry. Meanwhile, the proposed biosensor was used to evaluate the toxicity of thiram in fruit samples. Results indicated that the toxicity of thiram cannot be ignored even at a low residual concentration in food (≤5 mg/kg). In conclusion, the developed sensor showed excellent sensitivity, stability, and reliability, which provided a great capacity for the convenient toxicity evaluation of thiram residue in food.

Genome-Scale Mutational Analysis of Cathode-Oxidizing Thioclava electrotropha ElOx9T.

Extracellular electron transfer (EET) – the process by which microorganisms transfer electrons across their membrane(s) to/from solid-phase materials – has implications for a wide range of biogeochemically important processes in marine environments. Though EET is thought to play an important role in the oxidation of inorganic minerals by lithotrophic organisms, the mechanisms involved in the oxidation of solid particles are poorly understood. To explore the genetic basis of oxidative EET, we utilized genomic analyses and transposon insertion mutagenesis screens (Tn-seq) in the metabolically flexible, lithotrophic Alphaproteobacterium Thioclava electrotropha ElOx9T. The finished genome of this strain is 4.3 MB, and consists of 4,139 predicted ORFs, 54 contain heme binding motifs, and 33 of those 54 are predicted to localize to the cell envelope or have unknown localizations. To begin to understand the genetic basis of oxidative EET in ElOx9T, we constructed a transposon mutant library in semi-rich media which was comprised of >91,000 individual mutants encompassing >69,000 unique TA dinucleotide insertion sites. The library was subjected to heterotrophic growth on minimal media with acetate and autotrophic oxidative EET conditions on indium tin oxide coated glass electrodes poised at –278 mV vs. SHE or un-poised in an open circuit condition. We identified 528 genes classified as essential under these growth conditions. With respect to electrochemical conditions, 25 genes were essential under oxidative EET conditions, and 29 genes were essential in both the open circuit control and oxidative EET conditions. Though many of the genes identified under electrochemical conditions are predicted to be localized in the cytoplasm and lack heme binding motifs and/or homology to known EET proteins, we identified several hypothetical proteins and poorly characterized oxidoreductases that implicate a novel mechanism(s) for EET that warrants further study. Our results provide a starting point to explore the genetic basis of novel oxidative EET in this marine sediment microbe.

Synthesis, characterization, electrochemical, spectroelectrochemical and dye-sensitized solar cell properties of Phthalocyanines Containing Carboxylic Acid Anchoring Groups as photosensitizer

Peripherally tetra-4-carboxyethylphenoxy substituted oxotitanium (IV), cobalt(II), zinc(II) and metal free phthalocyanines were synthesized to research the sensitizing abilities of these dye molecules in standard dye-sensitized solar cells (DSSCs). All the synthesized phthalocyanine complexes have been characterized by using elemental analyses, UV–Vis, FT-IR, 1H NMR and MALDI-TOF MS spectroscopic techniques. Electrochemistry of metallo phthalocyanines (MPcs) were studied with electrochemical and in-situ spectroelectrochemical measurements. H2Pc (7) and ZnPc (5) illustrated similar Pc based electron transfer reactions. Differently, CoPc (6) and TiOPc (4) illustrated metal based redox reactions, which enhanced the redox functionality of these complexes. Metal based reductions for CoPc (6) and TiOPc (4) were recorded in addition to the Pc based one. In-situ spectroelectrochemical measurements supported the proposed voltametric mechanism. Moreover, the color and spectra of the electrogenerated species were determined with the in-situ spectroelectrochemical analyses to predict possible optoelectrochemical application of the complexes. Pronounced optical and color changes during the electrolysis of the complexes indicated electrooptical and possible solid state electrochemical functionality of the complexes. TiO2 semiconductor on the fluoride doped indium tin oxide coated glass electrode (FTO) was decorated with H2Pc (7) and TiOPc (4) bearing four carboxyl anchoring groups and they were first of all tested as possible dye for the DSSC. H2Pc (7), TiOPc (4), CoPc (6) and ZnPc (5) dyes used in DSSCs showed 2.9%, 3.3%, 1.02% and 2.2% of power conversion efficiencies respectively.

Size-Dependent Ripening of Gold Nanoparticles through Repetitive Electrochemical Surface Oxidation-Reduction Cycling

Here we describe the electrochemical size stability of 1.6, 4.1, and 15.1 nm diameter Au nanoparticles (NPs) supported on indium tin oxide-coated glass electrodes (glass/ITO). Anodic stripping voltammetry (ASV) and the electrochemically-measured total surface area-to-volume ratio (SA/V) provide the NP size following surface oxidation-reduction cycling from −0.2 to 1.6 V (vs Ag wire) in 0.1 M HClO4. After 1000 oxidation-reduction cyclic voltammetry (CV) scans, the relative size increases by a factor of 12, 7, and 2 for the 1.6, 4.1, and 15.1 nm diameter Au NPs, respectively. The relative size increase is largest for the smallest NPs, also confirmed by electron microscopy, indicating their lower size stability towards surface oxidation-reduction cycling. The size increase is fastest within the first 200 cycles, which decreases with a further increase in the number of cycles until the Au NP diameter stabilizes. The size transformation is more dramatic at higher Au NP electrode coverage and 30%–100% of the Au dissolves during cycling, depending on the coverage and NP size. Various potential cycling and holding profiles show that the Au NP size increases during reduction of the oxide layer, consistent with an electrochemical Ostwald ripening mechanism.

A Bilayer Structure Composed of Mg|Co-MnO2 Deposited on a Co(OH)2 Film to Realize Selective Oxygen Evolution from Chloride-Containing Water.

A fluorine-doped tin oxide-coated glass electrode modified with a bilayer film of underlying α-Co(OH)2 and overlying Mg-intercalated and Co-doped δ-type (layered) MnO2 (Mg|Co-MnO2) preferentially yielded oxygen with a Faradaic efficiency as high as 79% in the presence of chloride ions at high concentration (0.5 M). This noble metal-free electrode was fabricated by cathodic electrolysis of aqueous Co(NO3)2 followed by anodic electrolysis of a mixture of Mn2+, Co2+, and cetyltrimethylammonium (CTA+) ions in water. The CTA+ ions accommodated in the interlayer spaces of Co-doped δ-MnO2 were replaced with Mg2+ by ion exchange. The upper Mg|Co-MnO2 could effectively block the permeation of Cl- ions and allow only H2O and O2, while the under α-Co(OH)2 acted as an oxidation catalyst for the H2O penetrated through the upper coating. Thus, the oxygen evolution reaction (OER) was preferred to the chlorine evolution reaction (CER). In artificial seawater (pH 8.3), the blocking effect against Cl- decreased because of ion exchange of the intercalated Mg2+ ions with Na+ in solution, but the OER efficiency still remained at 57%, much higher than that (28%) without the upper Mg|Co-MnO2. This demonstrates that the interlayer spaces between MnO2 layers acted as pathways for H2O molecules to reach the active sites of the underlying Co(OH)2. Density functional theory (DFT) calculations revealed that the most stable structure of hydrated Mg2+ ion, in which a part of coordinated H2O molecules is hydrolyzed, has less affinity toward Cl- ion than that of hydrated Na+ ion.

Electrochemistry, electropolymerization and electrochromism of novel phthalocyanines bearing morpholine groups

In this work, 4-(4-((4-morpholinophenylimino)methyl)phenoxy)phthalonitrile (3) and it’s peripherally tetra substituted metal-free (4), zinc(II) (5), copper(II) (6) and nickel(II) (7) phthalocyanines were synthesized for the first time. The structural characterization of these novel compounds were performed with FT-IR, 1H NMR, 13C NMR, UV–Vis and mass spectroscopy. Electrochemical and spectroelectrochemical characterizations of phthalocyanines (4–7) showed that while all phthalocyanines went to characteristics phthalocyanine ring and/or metal based reduction processes during the negative potential scans, all complexes were coated on the working electrode during the oxidation processes due to the cationic electropolymerizations of the 4-(4-((4-morpholinophenylimino)methyl)phenoxy) substituents. Changing the metal centers of phthalocyanine ring influenced the redox processes due to the different redox activities and effective nuclear charges of the metal centers. In addition to the electropolymerization ability of 4-(4-((4-morpholinophenylimino)methyl)phenoxy) substituent slightly affected the reversibility and peak positions of the redox processes. Indium tin oxide coated glass electrode (ITO) was coated with electropolymerized films of phthalocyanines to construct ITO/Poly-Phthalocyanine and these electrodes were tested as a potential electrochromic material. ITO/Poly-Phthalocyanine provided color change between green and blue with 1.2 s switching time, 18% optical contrast and 100% optical stability with 50 cronoamperometric (CA) cycles. These studies indicated possible usage of the electropolymerized films of phthalocyanines as possible building blocks for advanced electrochromic devices needing green-blue color change.

Electrochemical Detection of Dopamine in Real Samples by an Indium Tin Oxide-Coated Glass Electrode Modified with Carbon Nanotubes

Electrochemical Detection of Dopamine in Real Samples by an Indium Tin Oxide-Coated Glass Electrode Modified with Carbon Nanotubes

Electrochemical sensor for detection of mercury (II) ions in water using nanostructured bismuth hexagons

This study presents a systematic observation of the ability of bismuth nanostructures to detect trace amounts of mercury. Nanostructured hexagons of bismuth were synthesized using electrochemical deposition with potentiostatic mode on indium tin oxide-coated glass electrodes. Regular hexagons composed of nano-sized hexagonal building blocks (edge length $$\approx 80$$ to 700 nm) with well-defined edges were observed in scanning electron microscopy studies. X-ray diffraction pattern indicates the presence of polycrystalline bismuth and bismuth oxide in rhombohedral and cubic phases, respectively. X-ray photoelectron spectroscopy was done to analyze the chemical structure of the prepared nanostructures. Square wave anodic stripping voltammetry technique confirms that these nanostructured electrodes are highly sensitive to $$Hg^{2+}$$ ions down to concentrations as low as 0.74 ppb.

Experimental and Theoretical Investigations of an Electrochromic Azobenzene and 3,4‐Ethylenedioxythiophene‐based Electrochemically Formed Polymeric Semiconductor

An electrochromic material based on azobenzene and 3,4-ethylenedioxythiophene (EDOT) semiconducting layer was electrochemically deposited on an indium tin oxide coated glass electrode. Chemical synthesis of the azobenzene and EDOT-based chromophore (DAE) and electrochemical formation of its corresponding polymer (pDAE) are reported. The electrochromic properties of the synthesized polymer pDAE were investigated by electrochemical and spectroelectrochemical methods. pDAE exhibited an optical bandgap of 1.82 eV and three distinct colored states in its reduced, neutral, and oxidized forms. The pDAE polymer showed 44 % optical contrast at 710 nm between its reduced and oxidized states and a fast electrochromic switching time of 1.0 s. The frontier molecular orbitals, Raman shifts, and semiconducting properties of this electrochromic polymer were evaluated by density functional theory calculations. The optical absorption bands of the polymer charged states were assigned and investigated.

Voltammetric determination of copper and zinc in water using a Ruthenium bipyridyl/Nafion-modified indium tin oxide-coated glass electrode

Chemically-modified Indium Tin Oxide (ITO) coated glass substrates were fabricated by depositing Nafion thin films doped with tris (2,2’-bipyridyl) ruthenium(II) dichloride hexahydrate via drop coating deposition technique. The Nafion volume concentration in the film is 1% (v/v) and the mediator concentration is 5 mg per 1 mL Nafion. The chemically-modified electrodes were characterized by cyclic voltammetry (CV) and were used as working electrodes to detect varying concentrations of copper (Cu2+) and zinc (Zn2+) in a 0.1 M NaCl supporting electrolyte solution via Anodic Stripping Voltammetry (ASV). Cu2+ and Zn2+ ions were successfully determined by ASV. The limits of detection for Cu2+ and Zn2+ were 0.1 ppm and 0.7 ppm, respectively. The modified electrodes were used to determine the presence of Cu2+ and Zn2+ in different real water samples. The presence of Cu2+ was successfully determined in deep well, lake, and tap water samples, while the presence of Zn2+ was successfully determined in sea and tap water samples. Atomic Absorption Spectroscopy (AAS) results confirm the presence of Cu2+ and Zn2+ in the samples.

Luminescent Thin Films Composed of Nanosized Europium Coordination Polymers on Glass Electrodes.

Luminescent thin films composed of thermostable lanthanide coordination polymers on glass electrodes were prepared using a novel combination of micelle reactions and electrochemical deposition techniques. The micelle-encapsulated luminescent polymers were obtained by the polymerization of [Eu(hfa)3 ] (hfa=hexafluoroacetylacetonate) with bridging phosphine oxide ligands in micelles using a redox-active ferrocenyl-containing surfactant in water. Films were electrochemically deposited on indium tin oxide coated glass electrodes by potentiostatic polarization of micelle-encapsulated EuIII coordination polymers. The luminescence properties of the electrochemically deposited films were characterized by measuring their emission spectra, emission lifetimes and emission quantum yields.

ChemInform Abstract: Identification of a Nonanuclear {CoII9} Polyoxometalate Cluster as a Homogeneous Catalyst for Water Oxidation.

AbstractIn the presence of the polyanion {Co9(H2O)6(OH)3 (HPO4)2 (PW9O34)3}16‐ catalytic water electrolysis in a sodium phosphate buffer solution at neutral pH occurs on fluorine‐doped tin oxide coated glass electrodes at reasonable low overpotentials.

Electrochemical, electrochromic behaviour and effects of supporting electrolyte on nano-thin film of poly (3,4-ethylenedioxy thiophene)

3,4-Ethylenedioxy thiophene is polymerized electrochemically in p-toluene sulphonic acid (a), phosphate buffer (b) and borax buffer (c) on glassy carbon and Indium tin oxide (ITO) surface. The scan rate dependence studies of the polymer redox processes were carried out. A linear relationship was observed between the peak current and scan rate with good correlation, r2=0.998 indicating adsorption controlled behaviour of polymer film. The SEM photograph showed the differences in surface morphology of polymers modified electrode. The XRD studies revealed semi-crystalline nature of doped polymers. Spectroelectrochemical behaviors of Indium tin oxide coated glass electrode covered with thin film of poly-3,4-ethylenedioxythiophene a, b, c in 0.1M KCl were obtained at different electrode potentials between 1100 and 200nm. Poly-3,4-ethylenedioxythiophene-a, poly-3,4-ethylenedioxythiophene-b and poly-3,4-ethylenedioxythiophene-c film exhibits transparent clear blue, opaque violet and dark maroon colours respectively at reduced potential. Further probing the potential between 400mV and 800mV coated film shows greenish blue colour for poly-3,4-ethylenedioxythiophene-a, poly-3,4-ethylenedioxythiophene-b and poly-3,4-ethylenedioxythiophene -c shows opaque violet and yellowish maroon colours respectively. Increasing the applied potential between 1000mV and 1200mV over oxidation of polymer film shows dark greenish blue for poly-3,4-ethylenedioxythiophene -a, dark brown for poly-3,4-ethylenedioxythiophene-b and transparent red colour for poly-3,4-ethylenedioxythiophene-c. Electrochromic parameters such as colouration efficiency, response time and optical contrast were calculated for all three films.

Identification of a Nonanuclear {CoII9} Polyoxometalate Cluster as a Homogeneous Catalyst for Water Oxidation

The polyanion of formula {Co(9)(H(2)O)(6)(OH)(3)(HPO(4))(2)(PW(9)O(34))(3)}(16-) (Co(9)) contains a central nonacobalt core held together by hydroxo and hydrogen phosphate bridges and supported by three lacunary Keggin-type polyphosphotungstate ligands. Our data demonstrate that Co(9) is a homogeneous catalyst for water oxidation. Catalytic water electrolysis on fluorine-doped tin oxide coated glass electrodes occurs at reasonable low overpotentials and rates when Co(9) is present in a sodium phosphate buffer solution at neutral pH. We carried out our experiments with an excess of 2,2'-bipyridyl as the chelating agent for free aqueous Co(II) ions, in order to avoid the formation of a cobalt oxide film on the electrode, as observed for other polyoxometalate catalysts. In these conditions, no heterogeneous catalyst forms on the anode, and it does not show any deposited material or significant catalytic activity after a catalytic cycle. Co(9) is also an extremely robust catalyst for chemical water oxidation. It is able to continuously catalyze oxygen evolution during days from a buffered sodium hypochlorite solution, maintaining constant rates and efficiencies without any significant apparition of fatigue.

Oxidation of Highly Unstable <4 nm Diameter Gold Nanoparticles 850 mV Negative of the Bulk Oxidation Potential

Here we describe the oxidation of <4 nm diameter Au nanoparticles (NPs) attached to indium tin oxide-coated glass electrodes in Br(-) and Cl(-) solution. Borohydride reduction of AuCl(4)(-) in the presence of hexanethiol or trisodium citrate (15 min) led to Au NPs <4 nm in diameter. After electrochemical and ozone removal of the hexanthiolate ligands from the thiol-coated Au NPs, Au oxidation peaks appeared in the range 0-400 mV vs Ag/AgCl (1 M KCl), which is 850-450 mV negative of the bulk Au oxidation peak near 850 mV. The oxidation potential of citrate-coated Au NPs is in the 300-500 mV range and those of 4 and 12 nm diameter Au NPs in the 660-780 mV range. The large negative shift in potential agrees with theory for NPs in the 1-2 nm diameter range. The oxidation potential of Au in Cl(-) solution is positive of that in Br(-) solution, but the difference decreases dramatically as the NP size decreases, showing less dependence on the halide for smaller NPs.

Ionic liquid assisted synthesis of nano Pd–Au particles and application for the detection of epinephrine, dopamine and uric acid

Nano Pd–Au particles have been electrochemically fabricated utilizing ionic liquid as green electrolyte (1-Butyl-3-methylimidazolium tetrafluoroborate). Nano Pd–Au particles modified glassy carbon electrode (GCE) and indium tin oxide coated glass electrodes were examined using atomic force microscopy, field emission scanning electron microscope and X-ray diffraction studies. Electrodeposited nano Pd–Au particles' average diameter was found as 33nm. Nano Pd–Au particle modified GCE was electrochemically active and stable in various pH solutions. The proposed nano particle modified GCE reduces the over potential and shows the well defined oxidation peaks for the detection of epinephrine and simultaneous determination of dopamine and uric acid (in pH 7.0 phosphate buffer solution) using cyclic voltammetry and differential pulse voltammetry.