Thiruppathi Murugan | National Taiwan University (original) (raw)
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Papers by Thiruppathi Murugan
Talanta, 2019
Simple aminophenol-based electrochemical probes for non-enzymatic, dual amperometric detection of... more Simple aminophenol-based electrochemical probes for non-enzymatic, dual amperometric detection of NADH and hydrogen peroxide, Talanta,
This thesis describes the oxygen, boronic acid functionalization of screen printed carbon electro... more This thesis describes the oxygen, boronic acid functionalization of screen printed carbon electrode (SPCE) and utilization of those functional moieties for versatile sensor applications. In-situ generated oxygen functionalities along with edge/defect sites of preanodized SPCE (SPCE*) is used for metal free oxidation of poly aromatic hydrocarbons (PAHs). In later sections, we report preparation of stimuli responsive boronic acid based probes on SPCE via both electrochemical as well as chemical routes. In the electrochemical method, 4-Aminophenylboronic acid (4-APBA) has been dimerized and polymerized on SPCE and SPCE* with or without fluoride. The dimer-modified electrode possesses dual functionalities (R-N=N-R' and -B(OH)2) which makes its suitable for selective detection of hypochlorite (i.e., free chlorine), fluoride and sugar molecules, respectively. In chemical method, a new approach for rapid oxidative polymerization of aminophenylboronic acid is described via reduction of ...
Electrochemistry Communications, 2016
Abstract We report here the application of “preanodized” screen printed carbon electrode without ... more Abstract We report here the application of “preanodized” screen printed carbon electrode without the need of adding catalysts for the adsorption and subsequent oxidation of polyaromatic hydrocarbons (PAHs). By suitably defining the preanodization condition, controlled amount of surface defects and oxygen functionalities are created to fulfill this purpose. Characterization of the modified electrodes and oxidized products specifies that both oxygen functionalities and edge/defect sites play a critical role in the adsorption of PAHs and their oxidation at lower overpotential. The results can assist in designing systems for efficient detection and toxicity degradation of a wide range of PAHs.
Microchimica Acta
AbstractThe authors report on the electrochemical process for the modification of a screen printe... more AbstractThe authors report on the electrochemical process for the modification of a screen printed carbon electrode (SPCE) with an azo-functionalized dimer of 4-amino phenylboronic acid. The dimer is prepared on the surface of the SPCE through the formation of azo bond, and the presence of the dimer is confirmed by cyclic voltammetry, X-ray photoelectron spectroscopy and functional group specific sensing studies. Specifically, this unique dimer-modified electrode possesses dual functionalities (R–N=N-R’ and –B(OH)2) which makes its suitable for selective detection of hypochlorite (i.e., free chlorine) and sugar molecules (demonstrated for glucose and fructose), respectively. The heterogeneous electron transfer rate constant is 7.89 s−1 which indicates a fast electron transfer process at the dimer-modified SPCE. The sensor, operated at a voltage of typically 0.05 V (vs. Ag/AgCl), gives a linear response in the 1 μM to 10 mM hypochlorite concentration range and has a sensitivity of 408.16 μA mM−1 cm−2 at neutral pH values. The catalytic rate constant is 49,872 M s−1 for free chlorine. By using hexacyanoferrate as an electrochemical probe and at a typical working voltage of 0.18 V (vs. Ag/AgCl), the sensor displays a linear response in the 1 to 500 μM fructose and glucose concentration range, with detection limits (for S/N = 3) of 0.24 μM for fructose and 0.36 μM for glucose. Graphical abstractSchematic of an electrochemically dimerized 4-aminophenylboronic acid through azo-functionalization route on preanodized screen printed carbon electrode (SPCE*). It was designed for voltammetric sensing of glucose, fructose and hypochlorite using boronic acid and azo moieties, respectively.
Talanta, 2019
Non enzymatic detection of NADH and H 2 O 2 is of practical significance for both environmental a... more Non enzymatic detection of NADH and H 2 O 2 is of practical significance for both environmental and biological prospective. However, there is no simple, straight forward electrochemical sensor available for sensing of them in real samples. Addressing this challenge, we report a simple stimuli responsive aminophenol, pre-anodized screen printed carbon electrode (SPCE*/AP) based electrochemical probes for dual detection of NADH and H 2 O 2. Aminophenol prepared and adsorbed on the electrode from aminophenylboronic acid via boronic acid depro-tection with H 2 O 2. The SPCE*/AP fabricated with this process was characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), Raman spectroscopy, UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). Amperometric detection results showed that SPCE*/AP electrodes exhibited linearity from 50 µM to 500 µM and from 200 µM to 2 mM with a detection limit (S/N = 3) of 4.2 µM and 28.9 µM for NADH and H 2 O 2 , respectively. Excellent reproducibility and selectivity for NADH and H 2 O 2 were observed for this electrochemical platform. In addition, the matrix effect was investigated further using the same technique to analyze NADH and H 2 O 2 in human urine samples, human serum samples, cell culture medium (containing 10% fetal bovine serum, FBS), and environmental water samples (tap water and rain water). Also, the present sensor demonstrated promising outcomes with living cells (normal cells and cancer cells).
In this work we report electrocatalytic oxidation and flow injection analysis of tuberculostatic ... more In this work we report electrocatalytic oxidation and flow injection analysis of tuberculostatic drug iso-niazid (INZ) based on a disposable and unmodified screen printed carbon electrode (SPCE). Instead of using chemically modified electrode to increase the sensitivity at low overpotential, the same purpose can be achieved simply by preanodization of a bare SPCE in a suitable electrolyte medium. Surface characterization of the as-preanodized electrode by X-ray photoelectron spectroscopy and Ram-an spectroscopy indicate that both oxygen functionalities and edge/defect sites effectively assist the INZ oxidation. Flow injection analysis extends its applicability with a wide linear range up to 1 mM and an enhanced sensitivity of 100 nA mM À1 with a low detection limit of 2.7 nM (S/ N = 3). These good analytical features accomplished with disposable and economical devices could make possible the implementation of this methodology for INZ on-line monitoring in pharmaceuticals.
The authors report on the electrochemical process for the modification of a screen printed carbon... more The authors report on the electrochemical process for the modification of a screen printed carbon electrode (SPCE) with an azo-functionalized dimer of 4-amino phenylboronic acid. The dimer is prepared on the surface of the SPCE through the formation of azo bond, and the presence of the dimer is confirmed by cyclic voltammetry, X-ray pho-toelectron spectroscopy and functional group specific sensing studies. Specifically, this unique dimer-modified electrode possesses dual functionalities (R–N=N-R' and –B(OH) 2) which makes its suitable for selective detection of hypochlo-rite (i.e., free chlorine) and sugar molecules (demonstrated for glucose and fructose), respectively. The heterogeneous electron transfer rate constant is 7.89 s −1 which indicates a fast electron transfer process at the dimer-modified SPCE. The sensor, operated at a voltage of typically 0.05 V (vs. Ag/ AgCl), gives a linear response in the 1 μM to 10 mM hypo-chlorite concentration range and has a sensitivity of 408.16 μA mM −1 cm −2 at neutral pH values. The catalytic rate constant is 49,872 M s −1 for free chlorine. By using hexacyanoferrate as an electrochemical probe and at a typical working voltage of 0.18 V (vs. Ag/AgCl), the sensor displays a linear response in the 1 to 500 μM fructose and glucose concentration range, with detection limits (for S/N = 3) of 0.24 μM for fructose and 0.36 μM for glucose.
We report here the application of " preanodized " screen printed carbon electrode without the nee... more We report here the application of " preanodized " screen printed carbon electrode without the need of adding catalysts for the adsorption and subsequent oxidation of polyaromatic hydrocarbons (PAHs). By suitably defining the preanodization condition, controlled amount of surface defects and oxygen functionalities are created to fulfill this purpose. Characterization of the modified electrodes and oxidized products specifies that both oxygen functionalities and edge/defect sites play a critical role in the adsorption of PAHs and their oxidation at lower overpotential. The results can assist in designing systems for efficient detection and toxicity degradation of a wide range of PAHs.
Talanta, 2019
Simple aminophenol-based electrochemical probes for non-enzymatic, dual amperometric detection of... more Simple aminophenol-based electrochemical probes for non-enzymatic, dual amperometric detection of NADH and hydrogen peroxide, Talanta,
This thesis describes the oxygen, boronic acid functionalization of screen printed carbon electro... more This thesis describes the oxygen, boronic acid functionalization of screen printed carbon electrode (SPCE) and utilization of those functional moieties for versatile sensor applications. In-situ generated oxygen functionalities along with edge/defect sites of preanodized SPCE (SPCE*) is used for metal free oxidation of poly aromatic hydrocarbons (PAHs). In later sections, we report preparation of stimuli responsive boronic acid based probes on SPCE via both electrochemical as well as chemical routes. In the electrochemical method, 4-Aminophenylboronic acid (4-APBA) has been dimerized and polymerized on SPCE and SPCE* with or without fluoride. The dimer-modified electrode possesses dual functionalities (R-N=N-R' and -B(OH)2) which makes its suitable for selective detection of hypochlorite (i.e., free chlorine), fluoride and sugar molecules, respectively. In chemical method, a new approach for rapid oxidative polymerization of aminophenylboronic acid is described via reduction of ...
Electrochemistry Communications, 2016
Abstract We report here the application of “preanodized” screen printed carbon electrode without ... more Abstract We report here the application of “preanodized” screen printed carbon electrode without the need of adding catalysts for the adsorption and subsequent oxidation of polyaromatic hydrocarbons (PAHs). By suitably defining the preanodization condition, controlled amount of surface defects and oxygen functionalities are created to fulfill this purpose. Characterization of the modified electrodes and oxidized products specifies that both oxygen functionalities and edge/defect sites play a critical role in the adsorption of PAHs and their oxidation at lower overpotential. The results can assist in designing systems for efficient detection and toxicity degradation of a wide range of PAHs.
Microchimica Acta
AbstractThe authors report on the electrochemical process for the modification of a screen printe... more AbstractThe authors report on the electrochemical process for the modification of a screen printed carbon electrode (SPCE) with an azo-functionalized dimer of 4-amino phenylboronic acid. The dimer is prepared on the surface of the SPCE through the formation of azo bond, and the presence of the dimer is confirmed by cyclic voltammetry, X-ray photoelectron spectroscopy and functional group specific sensing studies. Specifically, this unique dimer-modified electrode possesses dual functionalities (R–N=N-R’ and –B(OH)2) which makes its suitable for selective detection of hypochlorite (i.e., free chlorine) and sugar molecules (demonstrated for glucose and fructose), respectively. The heterogeneous electron transfer rate constant is 7.89 s−1 which indicates a fast electron transfer process at the dimer-modified SPCE. The sensor, operated at a voltage of typically 0.05 V (vs. Ag/AgCl), gives a linear response in the 1 μM to 10 mM hypochlorite concentration range and has a sensitivity of 408.16 μA mM−1 cm−2 at neutral pH values. The catalytic rate constant is 49,872 M s−1 for free chlorine. By using hexacyanoferrate as an electrochemical probe and at a typical working voltage of 0.18 V (vs. Ag/AgCl), the sensor displays a linear response in the 1 to 500 μM fructose and glucose concentration range, with detection limits (for S/N = 3) of 0.24 μM for fructose and 0.36 μM for glucose. Graphical abstractSchematic of an electrochemically dimerized 4-aminophenylboronic acid through azo-functionalization route on preanodized screen printed carbon electrode (SPCE*). It was designed for voltammetric sensing of glucose, fructose and hypochlorite using boronic acid and azo moieties, respectively.
Talanta, 2019
Non enzymatic detection of NADH and H 2 O 2 is of practical significance for both environmental a... more Non enzymatic detection of NADH and H 2 O 2 is of practical significance for both environmental and biological prospective. However, there is no simple, straight forward electrochemical sensor available for sensing of them in real samples. Addressing this challenge, we report a simple stimuli responsive aminophenol, pre-anodized screen printed carbon electrode (SPCE*/AP) based electrochemical probes for dual detection of NADH and H 2 O 2. Aminophenol prepared and adsorbed on the electrode from aminophenylboronic acid via boronic acid depro-tection with H 2 O 2. The SPCE*/AP fabricated with this process was characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), Raman spectroscopy, UV-visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). Amperometric detection results showed that SPCE*/AP electrodes exhibited linearity from 50 µM to 500 µM and from 200 µM to 2 mM with a detection limit (S/N = 3) of 4.2 µM and 28.9 µM for NADH and H 2 O 2 , respectively. Excellent reproducibility and selectivity for NADH and H 2 O 2 were observed for this electrochemical platform. In addition, the matrix effect was investigated further using the same technique to analyze NADH and H 2 O 2 in human urine samples, human serum samples, cell culture medium (containing 10% fetal bovine serum, FBS), and environmental water samples (tap water and rain water). Also, the present sensor demonstrated promising outcomes with living cells (normal cells and cancer cells).
In this work we report electrocatalytic oxidation and flow injection analysis of tuberculostatic ... more In this work we report electrocatalytic oxidation and flow injection analysis of tuberculostatic drug iso-niazid (INZ) based on a disposable and unmodified screen printed carbon electrode (SPCE). Instead of using chemically modified electrode to increase the sensitivity at low overpotential, the same purpose can be achieved simply by preanodization of a bare SPCE in a suitable electrolyte medium. Surface characterization of the as-preanodized electrode by X-ray photoelectron spectroscopy and Ram-an spectroscopy indicate that both oxygen functionalities and edge/defect sites effectively assist the INZ oxidation. Flow injection analysis extends its applicability with a wide linear range up to 1 mM and an enhanced sensitivity of 100 nA mM À1 with a low detection limit of 2.7 nM (S/ N = 3). These good analytical features accomplished with disposable and economical devices could make possible the implementation of this methodology for INZ on-line monitoring in pharmaceuticals.
The authors report on the electrochemical process for the modification of a screen printed carbon... more The authors report on the electrochemical process for the modification of a screen printed carbon electrode (SPCE) with an azo-functionalized dimer of 4-amino phenylboronic acid. The dimer is prepared on the surface of the SPCE through the formation of azo bond, and the presence of the dimer is confirmed by cyclic voltammetry, X-ray pho-toelectron spectroscopy and functional group specific sensing studies. Specifically, this unique dimer-modified electrode possesses dual functionalities (R–N=N-R' and –B(OH) 2) which makes its suitable for selective detection of hypochlo-rite (i.e., free chlorine) and sugar molecules (demonstrated for glucose and fructose), respectively. The heterogeneous electron transfer rate constant is 7.89 s −1 which indicates a fast electron transfer process at the dimer-modified SPCE. The sensor, operated at a voltage of typically 0.05 V (vs. Ag/ AgCl), gives a linear response in the 1 μM to 10 mM hypo-chlorite concentration range and has a sensitivity of 408.16 μA mM −1 cm −2 at neutral pH values. The catalytic rate constant is 49,872 M s −1 for free chlorine. By using hexacyanoferrate as an electrochemical probe and at a typical working voltage of 0.18 V (vs. Ag/AgCl), the sensor displays a linear response in the 1 to 500 μM fructose and glucose concentration range, with detection limits (for S/N = 3) of 0.24 μM for fructose and 0.36 μM for glucose.
We report here the application of " preanodized " screen printed carbon electrode without the nee... more We report here the application of " preanodized " screen printed carbon electrode without the need of adding catalysts for the adsorption and subsequent oxidation of polyaromatic hydrocarbons (PAHs). By suitably defining the preanodization condition, controlled amount of surface defects and oxygen functionalities are created to fulfill this purpose. Characterization of the modified electrodes and oxidized products specifies that both oxygen functionalities and edge/defect sites play a critical role in the adsorption of PAHs and their oxidation at lower overpotential. The results can assist in designing systems for efficient detection and toxicity degradation of a wide range of PAHs.