50673-96-6Relevant articles and documents
Mechanistic insights into phenol oxidation by a copper(II) complex of a pyridine- And amide-containing copolymer in an aqueous medium
Lykourinou, Vasiliki,Ming, Li-June
, p. 375 - 381 (2015)
A CuII complex of a pyridine- and amide-containing copolymer (Cu-P1) exhibits effective activity toward phenol hydroxylation in 50% aqueous methanol solution at apparent pH 8.0 and 25°C. The complex shows significant first-order rate accelerations of 4.2 × 105 and 1.4 × 105 relative to phenol autoxidation in air and in the presence of 20 mM H2O2, respectively. The reaction mechanisms with H2O2 and air are different on the basis of (a) the different activity profiles for Cu binding, (b) the different deuterium kinetic isotope effects (2.8 in 20 mM H2O2 and 1.2 aerobically), and (c) the formation of a dinuclear substrate-(Cu-P1) complex with H2O2 but a mononuclear one aerobically. The mechanism in the presence of H2O2 is consistent with that of the type-3 dicopper tyrosinase. Although oxidized di-CuII tyrosinase can only use H2O2 for phenol hydroxylation, CuII-P1 can use either air or H2O2 for this process. The studies herein introduce a versatile chemical system for the further exploration of Cu-oxygen chemistry and other types of metal-centered chemistry and for the aerobic degradation of aromatic compounds in environmental and green chemistry.
Carbon supported olivine type phosphate framework: A promising electrocatalyst for sensitive detection of dopamine
Nehru, Raja,Chen, Shen-Ming
, p. 27775 - 27785 (2018)
In this study, a layered olivine-type LiMnPO4/functionalized-multiwall carbon nanotube (f-MWCNTs) composite is used as an electrochemically active material for the real-time detection of dopamine. A wet-chemical ultrasonication process is used to combine LiMnPO4 with f-MWCNTs at room temperature. The composite was subjected to various structural, morphological and electrochemical studies. The blending of olivine-type LiMnPO4 into the f-MWCNTs is revealed by TEM analysis. The electrochemical activities of the LiMnPO4/f-MWCNTs composite are systematically investigated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) for the real-time detection of dopamine. Furthermore, the applicability of the as prepared LiMnPO4/f-MWCNTs composite was extended for the detection of human serum (E48) and rat brain-serum (C7) samples with satisfactory recoveries for the real-time applications. All these studies revealed that the layered olivine-type LiMnPO4/f-MWCNTs composite is a potential candidate in the field of electrochemical sensing.
The effect of the buffering capacity of the supporting electrolyte on the electrochemical oxidation of dopamine and 4-methylcatechol in aqueous and nonaqueous solvents
Chen, Shanshan,Tai, Kah Yieng,Webster, Richard D.
, p. 1492 - 1499 (2011)
Dopamine was electrochemically oxidized in aqueous solutions and in the organic solvents N,N-dimethyl-formamide and dimethylsulfoxide containing varying amounts of supporting electrolyte and water, to form dopamine ortho-quinone. It was found that the electrochemical oxidation mechanism in water and in organic solvents was strongly influenced by the buffering properties of the supporting electrolyte. In aqueous solutions close to pH 7, where buffers were not used, the protons released during the oxidation process were able to sufficiently change the localized pH at the electrode surface to reduce the deprotonation rate of dopamine ortho-quinone, thereby slowing the conversion into leucoaminochrome. In N,N-dimethylformamide and dimethylsulfoxide solutions, in the absence of buffers, dopamine was oxidized to dopamine ortho-quinone that survived without further reaction for several minutes at 25 °C. The voltammetric data obtained in the organic solvents were made more complicated by the presence of HCl in commercial sources of dopamine, which also underwent an oxidation process. Copyright
Magnetic Flower-like Fe-Doped CoO Nanocomposites with Dual Enzyme-like Activities for Facile and Sensitive Determination of H2O2and Dopamine
Lian, Jiajia,He, Yanlei,Li, Ning,Liu, Pei,Liu, Zhenxue,Liu, Qingyun
, p. 1893 - 1901 (2021)
Herein, a new series of magnetic Fe-doped CoO nanocomposites (Fe-CoO NCs) with dual enzyme-like activities (peroxidase and oxidase) were successfully synthesized. The molar ratio of Fe3+/Co2+ salts during the solvothermal process determined the morphology and catalytic activity of the NCs. Among them, the flower-like 0.15Fe-CoO NCs showed high peroxidase-mimicking activity over a wider pH range of 4-5 and a temperature range of 30-50 °C. Such nanozymes were applied for constructing a facile and sensitive colorimetric sensor to detect H2O2 and dopamine (DA) in the linear ranges of 6-20 and 2-10 μM with limits of detection (LODs) of 4.40 and 1.99 μM, respectively. The excellent magnetic separation performance and successful DA detection in human urine samples validated the promising application of CoO-based nanozymes in medical diagnosis. The superior catalytic behaviors of 0.15Fe-CoO NCs could be ascribed to the high surface area, open mesoporous structure, increased surface active species, and the facile redox of Fe3+/Fe2+ and Co3+/Co2+. Based on the results of the fluorescent probe and radical trapping tests, the possible mechanism that Fe doping promoted the decomposition of H2O2 to produce hydroxyl radical (.OH) and superoxide radical (.O2-) was proposed.
Carbon-doped h-BN for the enhanced electrochemical determination of dopamine
Ouyang, Huiying,Li, Weifeng,Long, Yumei
, (2021)
Since dopamine (DA) is one of the central neurotransmitters and plays an important role in the human metabolism, its accurate detection is crucial for the diagnosis of DA-linked diseases. Herein, we demonstrated a novel electrochemical sensor for DA detection based on carbon-doped hexagonal boron nitrogen (C-hBN). C-hBN was prepared via a thermal polymerization process using melamine borate as a precursor. The successful C-doping was evidenced by fourier transform infrared (FTIR), photoluminescent (PL) and x-ray photoelectron spectroscopy (XPS). The carbon-doping can increase reactive sites and facilitate electrons transfer in h-BN, which was confirmed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The C-hBN modified glassy carbon electrode (C-hBN/GCE) exhibited the enhanced electrocatalytic activity toward DA redox, whose CV peak current is 2.8 and 4.3 times higher than those of pure h-BN modified and bare GCEs, respectively. Based on CV method, the C-hBN/GCE presented a low detection limit of 5.8 nM (S/N = 3) and a sensitivity of 2037 μA?mM?cm?2. The linear response ranges were over the DA concentrations of 0.01–40 μM and 40–300 μM, respectively. In addition, the sensor was applied to detect DA in real samples including human serum and urine, and satisfactory results were achieved. The results suggested that the defect-engineered h-BN holds great potential for the development of electroanalytical devices with high-performance.
Simultaneous determination of dopamine and uric acid in the presence of high ascorbic acid concentration using cetyltrimethylammonium bromide-polyaniline/activated charcoal composite
Govindasamy, Mani,Chen, Shen-Ming,Mani, Veerappan,Sathiyan, Anandaraj,Merlin, Johnson Princy,Al-Hemaid, Fahad M. A.,Ali, M. Ajmal
, p. 100605 - 100613 (2016)
We describe a simple, low-cost and mass producible composite made up of cetyltrimethylammonium bromide (CTAB) functionalized polyaniline (PANI) and activated charcoal (CTAB-PANI/AC) for simultaneous determination of dopamine (DA) and uric acid (UA). The composite formation was verified through scanning electron microscopy, electrochemical impedance spectroscopy and electrochemical methods. The CTAB-PANI/AC composite was used to modify a glassy carbon electrode (GCE) and the resulting modified electrode displayed excellent electrocatalytic activity to DA and UA and successfully separates their overlapped voltammetric peaks. The composite completely inhibits the AA signal and does not produce any voltammetric signal for AA up to 2 mM. The DA and UA can be selectively detectable up to detection limits of 0.06 (±0.006) μM and 0.20 (±0.008) μM, respectively. The effects of kinetics, analyte concentration and pH of the supporting electrolyte were investigated and optimized. The modified electrode has appreciable stability, repeatability and reproducibility. Besides, the practical feasibility of the sensor is demonstrated in biological samples, which delivered satisfactory recovery results.
Simple approach for the immobilization of horseradish peroxidase on poly-L-histidine modified reduced graphene oxide for amperometric determination of dopamine and H2O2
Vilian, A. T. Ezhil,Chen, Shen-Ming
, p. 55867 - 55876 (2014)
In this work, immobilization of horseradish peroxidase (HRP) on poly-L-histidine (P-L-His) modified reduced graphene oxide (RGO) was demonstrated. The HRP/P-L-His-RGO bio-nanocomposite film was prepared through layer-by-layer (LBL) assembly. Scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and UV-Vis spectroscopy were adopted to monitor the uniformity of the LBL assembly of the HRP/P-L-His-RGO bio-nanocomposite film. The immobilized HRP exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2). The catalysis currents showed a linear relationship with H2O2 concentration, ranging from 0.2 to 5000 μM. The detection limit (S/N = 3) of H2O2 was 0.05 μM. The apparent Michaelis-Menten constant (Km) was calculated to be 1.2 mM. Moreover, the modified electrode displayed a rapid response (5 s) to H2O2 with good stability and reproducibility. Based on the HRP/P-L-His-RGO bio-nanocomposite film, a third-generation reagentless biosensor was constructed for the determination of H2O2.
A new electrochemical sensor based on a nitrogen-doped graphene/CuCo2O4 nanocomposite for simultaneous determination of dopamine, melatonin and tryptophan
Tadayon,Sepehri
, p. 65560 - 65568 (2015)
A new nanocomposite based on nitrogen-doped graphene nanosheets/CuCo2O4 nanoparticles was prepared and used as an electrode material for simultaneous determination of dopamine, melatonin and tryptophan. For this purpose, CuCo2O4 nanoparticles were supported on porous nitrogen-doped graphene nanosheets by a simple method. The nanocomposite was characterized by transmission electron microscopy and X-ray diffraction spectroscopy. Incorporation of the prepared nanocomposite in a carbon paste electrode (CPE) increased the oxidation peak currents and reduced the overpotential of dopamine, melatonin and tryptophan. The new developed sensor was then employed for the simultaneous determination of target analytes with linear ranges of 0.010-3.0 μM, using differential pulse voltammetry. Detection limits of 0.0033, 0.0049 and 0.0041 μM were achieved for dopamine, melatonin and tryptophan, respectively. The selectivity of the method was studied and the results showed that the fabricated sensor is free from interference of organic compounds especially uric acid and ascorbic acid. Finally, the proposed electrochemical sensor was employed to determine analytes in urine, serum and pharmaceutical samples.
A novel ionic liquid functionalized graphene oxide supported gold nanoparticle composite film for sensitive electrochemical detection of dopamine
Li, Jianbo,Wang, Yanhui,Sun, Yuanling,Ding, Chaofan,Lin, Yanna,Sun, Weiyan,Luo, Chuannan
, p. 2315 - 2322 (2017)
A simple and sensitive electrochemical sensor for detection of dopamine has been developed based on ionic liquid functionalized graphene oxide supported gold nanoparticles (GO-IL-AuNPs) coated onto a glassy carbon electrode. The prepared graphene oxide, ionic liquid functionalized graphene oxide and GO-IL-AuNPs were characterized in detail by scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The electrochemical properties of the hybrid nanomaterials were evaluated through cyclic voltammetry and electrochemical impedance spectroscopy. Meanwhile, the activities of hybrid nanomaterials toward the oxidation of dopamine were analyzed via cyclic voltammetry and differential pulse voltammetry. The resulting sensor showed excellent electrocatalytic activity towards dopamine. Under the optimum conditions, differential pulse voltammetry was employed to detect ultra-trace amounts of dopamine, for which a wide linear range of 7 nM to 5 μM and a limit of detection 2.3 nM (S/N = 3) were obtained. The proposed sensor exhibited excellent accuracy and precision and the relative standard deviation (RSD) was less than 5%. The highly sensitive sensor was successfully used for accurate determination of the content of dopamine in practical samples.
One step facile synthesis of silver nanoparticles for the simultaneous electrochemical determination of dopamine and ascorbic acid
Vidya,Kumara Swamy,Schell, Mark
, p. 298 - 305 (2016)
A silver nanoparticles modified carbon paste electrode (MCPE) was developed for the detection of dopamine using voltammetric techniques. The silver nanoparticles (AgNPs) were synthesized through a biological method by using leaf extract act as a reducing agent. The prepared AgNPs were characterized by X-ray diffraction (XRD) and UV-visible absorption spectroscopy (UV-vis). AgNPs are ideally suited for implementation in electrochemical applications due to their high electrical conductivity, high heterogeneous electron transfer rate, and low production cost. The electrochemical response of dopamine at a MCPE prepared with AgNPs is compared with the response of surfactant assisted synthesized AgNPs (S-AgNPs). The effect of pH suggests that an equal number of protons and electrons are involved in the electrochemical oxidation of dopamine. Differential pulse voltammetric technique (DPV) was used for the simultaneous determination of dopamine (DA), ascorbic acid (AA) and uric acid (UA). The peak potential separations for DA-AA and DA-UA were about 181 mV and 168 mV respectively, and the detection limit was 0.085 μM for DA. This work presents a simple approach to the determination of DA in the presence of AA and UA.
Characterization of products from the reactions of dopamine quinone with N-acetylcysteine
Xu, Rongda,Huang, Xin,Kramer, Karl J.,Hawley, M. Dale
, p. 110 - 126 (1996)
The reactions between electrochemically prepared dopamine (DA) quinone and N-cetylcysteine (NACγSH), a protein model nucleophile, have been investigated at pH 7 and pH 2. Major products were purified by semipreparative reversed-phase liquid chromatography and identified by mass spectrometry and nuclear magnetic resonance spectroscopy to be nucleophilic addition products of the quinone with NACγSH. The principal product is the monoaddition adduct of the quinone at C(5) of the ring, 5-5-(N-acetylcysteinyl)dopamine. The diaddition adduct of the quinone at C(2) and C(5) of the ring, 2,5-S,S'-di(N-acetylcysteinyl)dopamine, and the monoaddition product at C(2) of the ring, 2-S-(N-acetylcysteinyl)dopamine, are produced to lesser extents. The relative molar ratio of 2-S-(N-acetylcysteinyl)dopamine, 5-S-(N-acetylcysteinyl)dopamine, and 2,5-S,S'-di-(N-acetylcysteinyl)dopamine produced at pH 7 is approximately 8:59:33, whereas at pH 2 the ratio is 10:89:1. The uv/vis spectroscopic analysis shows that the two monoaddition products have maxima at 258 and 294 nm, whereas the diaddition product has a maximum at 276 nm and a shoulder at 302 nm. Cyclic voltammetry and chronoamperometry demonstrate that these adducts are oxidized more readily than DA, which causes the anodic current for the oxidation of DA in the presence of NACγSH to be kinetically controlled by the rates of the addition reactions. A reaction scheme is proposed for the formation of these products.
Detection of the neurotransmitter dopamine by a glassy carbon electrode modified with self-assembled perovskite LaFeO3 microspheres made up of nanospheres
Thirumalairajan,Girija,Mastelaro, Valmor R.,Ganesh,Ponpandian
, p. 25957 - 25962 (2014)
In this paper we report the detection of the neurotransmitter dopamine by an LaFeO3 microsphere-modified electrode in which the microspheres are made up of nanospheres. The morphology, structure and composition of the prepared nanostructure were characterized using SEM, TEM, XRD and XPS, and the electrocatalytic properties were investigated using cyclic voltammetry and amperometric studies. The modified electrodes markedly increased the efficiency of the electrocatalytic oxidation of dopamine. The biosensor exhibited high sensitivity at a low detection limit of 59 nM and wide linear range from 2 × 10-8 to 1.6 × 10-6 M (R = 0.9983). More importantly, the sensor effectively avoids the interference of ascorbic acid and uric acid. A possible electrocatalytic mechanism has been proposed. The LaFeO3 microspheres are highly promising for the detection of dopamine because of their high selectivity, fast response and good sensitivity. the Partner Organisations 2014.
A copper hexacyanocobaltate nanocubes based dopamine sensor in the presence of ascorbic acid
Karikalan,Velmurugan,Chen,Chelladurai
, p. 48523 - 48529 (2016)
A novel copper hexacyanocobaltate based sensor was developed and its electrocatalytic behavior towards the oxidation of dopamine (DA) was demonstrated. Among the Prussian blue analogues, copper hexacyanocobaltate (CuHCC) exhibits unique electrochemical responses due to its bimetallic combination of copper and cobalt. As-prepared CuHCC shows a well-defined cubic structure with an average size of around 252 nm, which was confirmed by XRD and FE-SEM. Raman spectroscopy confirmed the coordination behavior of both the metal and ligand in CuHCC, which existed as CoIII-CN-CuII and CoII-CN-CuIII. The as-prepared CuHCC was used for the first time in DA detection and provided a better platform as a DA sensor. The electrocatalytic activity of CuHCC towards dopamine was examined by cyclic and differential pulse voltammetry. The CuHCC fabricated sensor shows a wide linear range from 0.1 to 350 μmol L-1 and low detection limit of 19 nmol L-1. The sensor reported herein displays excellent sensitivity, high stability and appreciable reproducibility for DA oxidation.
Voltammetric resolution of dopamine in the presence of ascorbic acid and uric acid at poly (calmagite) film coated carbon paste electrode
Chandra, Umesh,Kumara Swamy,Gilbert, Ongera,Sherigara
, p. 7166 - 7174 (2010)
The poly (calmagite) film was synthesized on the surface of carbon paste electrode by electrochemical method. The synthesized polymer film coated electrode exhibits excellent electrocatalytic activity towards the detection of dopamine at neutral pH. The scan rate effect was found to be adsorption controlled electrode process. The concentration effect of dopamine was studied. The redox peak potentials of dopamine were depend on pH. This polymer film coated electrode was very good at simultaneous study of dopamine in the presence of high concentrated ascorbic acid and uric acid. The incorporation study was done by varying the concentration of one species while other two are kept constant. The proposed method was applied to the detection of dopamine in injection samples.
GdTiO3 perovskite modified graphene composite for electrochemical simultaneous sensing of Acetaminophen and Dopamine
Anancia Grace, Arockiajawahar,Dharuman, Venkataraman,Hahn, Jong Hoon
, (2021/08/03)
A novel electrochemical biosensor was developed using GdTiO3 (GTO) perovskite prepared by sol-ge l(S) and hydrothermal (H) methods and decorated on few layered graphene for simultaneous sensing and quantification of dopamine (DA) and acetaminophen (ACE). The physical and structural characterization of the perovskites and composites were done using XRD, Raman, FTIR, XPS, and TEM analysis. Electrochemical characterization indicates higher activity for the GTO(S)-Gr composite modified electrode than the individual graphene, GTO(S) and GTO(H) component modified electrodes towards DA and ACE sensing. Simultaneous sensing in physiological buffer under optimized conditions exhibited wide linear ranges from 72 nM to 1.5 μM with lowest detection limit (LOD) 96.89 nM for DA and 50 nM to 1.5 μM with LOD 58.85 nM for ACE. The estimated sensitivity values are 3.357 × 10?5 A/nM and 2.177 × 10?5 A/nM, respectively for DA and ACE being higher than that of the literature reported for the graphene based metal oxide and perovskite sensors. The sensor showed high selectivity towards DA and ACE in the presence of co-interfering components like ascorbic acid, uric acid which may oxidize at the same potential.The binary composite was validated for DA and ACE sensing in practical applications using blood serum, tablet and urine samples and observed good signal recovery. The fabricated sensor was stable and showed good reproducibility.
