This work deals with the preliminary studies of ketamine by using several solid electrodes such a... more This work deals with the preliminary studies of ketamine by using several solid electrodes such as platinum, gold, nickel, compact graphite, titanium, glassy carbon and copper and the response was observed by comparing the results with the background observations. Cyclic, differential pulse, normal pulse and square wave voltammetry of ketamine hydrochloride was carried out at glassy carbon electrode. The results show a first sharp peak followed by a broad peak, which might have resulted from the products of first oxidation peak which is suggested for the electrochemical determination of ketamine in biological samples.
The amplitude estimation of a signal that is known only up to an unknown scaling factor, with int... more The amplitude estimation of a signal that is known only up to an unknown scaling factor, with interference and noise present, is of interest in several applications, including using the emerging quadrupole resonance (QR) technology for explosive detection. In such applications, a sensor array is often deployed for interference suppression. This paper considers the complex amplitude estimation of a known waveform signal whose array response is also known a priori. Two approaches, viz., the Capon and the maximum likelihood (ML) methods, are considered for the signal amplitude estimation in the presence of temporally white but spatially colored interference and noise. We derive closed-form expressions for the expected values and mean-squared errors (MSEs) of the two estimators. A comparative study shows that the ML estimate is unbiased, whereas the Capon estimate is biased downwards for finite data sample lengths. We show that both methods are asymptotically statistically efficient when the number of data samples is large but not when the signal-to-noise ratio (SNR) is high. Furthermore, we consider a more general scenario where the interference and noise are both spatially and temporally correlated. We model the interference and noise vector as a multichannel autoregressive (AR) random process. An alternating least squares (ALS) method for parameter estimation is presented. We show that in most cases, the ALS method is superior to the modelmismatched ML (M 3 L) method, which ignores the temporal correlation of the interference and noise.
Electro-catalytic activity of carbon based cerium doped lead dioxide anodes was investigated. Ele... more Electro-catalytic activity of carbon based cerium doped lead dioxide anodes was investigated. Electrodes were prepared by electrodepositing lead dioxide on carbon based substrates from a bath comprising 1.0 M lead(II) nitrate and 0.1 M and cerium(III) nitrate. Polarization studies of cerium doped lead dioxide electrodes were carried out using 1.0 mM iso-propanol at scan rate 100 mV/min in a three electrode system as shown in Figure 1. Electro-oxidation of chromium(III) to chromium(VI) was also carried out at the cerium doped lead dioxide electrode (area 30cm2) in a divided cell using 0.3 mM chromium(III) solution. Electrolysis was run for 20 hours and the electrolyte upon analysis by visible spectrophotometry yielded 77.4% conversion of chromium(III) to chromium(VI). Figure 1: Anodic polarization curves: (a) bare carbon, (b) cerium(III)-doped lead dioxide and (c) cerium(III)-doped lead dioxide in 1.0 mM iso-propanol. Background electrolyte: 1.0 M sulphuric acid and E in volts vs. Ag/AgCl,Cl- Reference: J. Kong, S. Shi, L. Kong, X. Zhua and J. Ni, Preparation and characterization of lead dioxide electrodes doped with different rare earth oxides, Electrochim. Acta, 53, 2048 (2007) *Presently at School of Chemistry Monash University Clayton Victoria 3800 Australia
Electrooxidation of p-Chloroaniline at Gold Electrode
ECS Transactions, 2014
Electrochemical oxidation of p-chloroaniline in 0.1 M sodium perchlorate in pure acetonitrile was... more Electrochemical oxidation of p-chloroaniline in 0.1 M sodium perchlorate in pure acetonitrile was studied on gold surface using cyclic and normal pulse voltammetry. Mechanistic interpretation of the voltammetric results is outlined in terms of peak (or half wave) potential dependence on scan rate and concentration of p-chloroaniline.
ABSTRACT Simulation of the cyclic voltammograms of dinitrobutoxy carbonyl fluorenone, t-butyl-2,4... more ABSTRACT Simulation of the cyclic voltammograms of dinitrobutoxy carbonyl fluorenone, t-butyl-2,4,7-trinitrofluorenone, 4-carboxyl-2,5,7-trinitrofluorenone, and 2,4,7-trinitrofluorenone in DMF/tetra-n-butylammonium perchlorate observed (R. O. Loufty et al., Can. J. Chem., 62, (1984) 1877) at mercury bead electrode were simulated by using softwares: CVSIM and ESP 2.4. Two cathodic and two anodic peaks were analysed. ESP took less time. In case of 2-alkyl-4,7-dinitrofluorenone, three anodic and two cathodic experimentally (R. O. Loufty et al., Can. J. Chem., 62, (1984) 1877) reported peaks were analysed by simulation.
Whereas reductive voltammetry of 1-bromopyrrolidin-2,5-dione (N-Bromosuccinimide), or SBr has bee... more Whereas reductive voltammetry of 1-bromopyrrolidin-2,5-dione (N-Bromosuccinimide), or SBr has been extensively studied in non-aqueous systems, relatively few papers have dealt with its electro-reduction in aqueous solutions. This paper describes voltammetry of 1-bromopyrrolidin-2,5-dione at platinum electrode in aqueous nitrate solution.
Voltammetry of N-Bromosuccinimide in Hexafluoropropan-2-ol
ECS Transactions, 2011
Electrochemical behaviour of N-bromosuccinimide (NBS, mp 174 ºC) was investigated in 1,1,1,3,3,3-... more Electrochemical behaviour of N-bromosuccinimide (NBS, mp 174 ºC) was investigated in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) by cyclic and pulsed voltammetry at platinum electrode. The cyclic voltammetric response was characterized by an irreversible reduction peak at around 0.7 V vs. SCE, and an anodic peak at about 0.1 V on reverse sweep. The possible mechanism for electro-reduction of NBS was outlined. In case of normal pulse voltammetry, a well-defined sigmoid-shaped curve was obtained. An increase in step time resulted in a significant cathodic shift. Differential pulse voltammetric response was consistent with the normal pulse behaviour, and featured a single peak centered at about 0.88 V. Linear variation of summit current with pulse height was observed.
The electrochemical oxidation of 4-hydroxybiphenyl was studied at the glassy carbon disk electrod... more The electrochemical oxidation of 4-hydroxybiphenyl was studied at the glassy carbon disk electrode using cyclic, normal pulse and differential pulse voltammetry in a solvent mixture. 4-Hydroxybiphenyl exhibited a well-defined, irreversible peak in 1:1 acetonitrile-water mixture containing 0.2 M sodium perchlorate at glassy carbon (0.125 cm2) electrode. In pulse voltammetry a linear relationship was obtained between the anodic peak current and concentration of 4-hydroxybiphenyl. The work needs optimization for the quantitative determination of 4-hydroxybiphenyl.
In this work electrochemical kinetics of nitrate reduction was investigated on solid cathodes suc... more In this work electrochemical kinetics of nitrate reduction was investigated on solid cathodes such as gold, titanium and aluminum. Enhancement of current density with increase in concentration of nitrate was observed with respect to the background in case of all electrode materials. The apparent electrochemical reaction order (14) for nitrate reduction was evaluated at various cathodes. The reaction order for the electro-reduction of nitrate at titanium showed dependence on electrode potential. Under the similar reactions conditions the electroreduction of nitrobenzene was also studied on the titanium electrode using cyclic voltammetry.
Voltammetry of Vinblastine Sulfate in Acetonitrile
ECS Transactions, 2010
Voltammetry of vinblastine sulfate was carried out in acetonitrile containing 0.2 M of sodium per... more Voltammetry of vinblastine sulfate was carried out in acetonitrile containing 0.2 M of sodium perchlorate. The studies were done when 21.4 mM pyridine was present in the above background solution. Vinblastine sulfate gave a single anodic peak representing irreversible electrochemical oxidation, as shown in both cases. Although, the behavior of vinblastine sulfate was almost comparable in the presence/absence of pyridine. However, the studies carried in the absence of pyridine were more significant.
This work deals with the preliminary studies of ketamine by using several solid electrodes such a... more This work deals with the preliminary studies of ketamine by using several solid electrodes such as platinum, gold, nickel, compact graphite, titanium, glassy carbon and copper and the response was observed by comparing the results with the background observations. Cyclic, differential pulse, normal pulse and square wave voltammetry of ketamine hydrochloride was carried out at glassy carbon electrode. The results show a first sharp peak followed by a broad peak, which might have resulted from the products of first oxidation peak which is suggested for the electrochemical determination of ketamine in biological samples.
The amplitude estimation of a signal that is known only up to an unknown scaling factor, with int... more The amplitude estimation of a signal that is known only up to an unknown scaling factor, with interference and noise present, is of interest in several applications, including using the emerging quadrupole resonance (QR) technology for explosive detection. In such applications, a sensor array is often deployed for interference suppression. This paper considers the complex amplitude estimation of a known waveform signal whose array response is also known a priori. Two approaches, viz., the Capon and the maximum likelihood (ML) methods, are considered for the signal amplitude estimation in the presence of temporally white but spatially colored interference and noise. We derive closed-form expressions for the expected values and mean-squared errors (MSEs) of the two estimators. A comparative study shows that the ML estimate is unbiased, whereas the Capon estimate is biased downwards for finite data sample lengths. We show that both methods are asymptotically statistically efficient when the number of data samples is large but not when the signal-to-noise ratio (SNR) is high. Furthermore, we consider a more general scenario where the interference and noise are both spatially and temporally correlated. We model the interference and noise vector as a multichannel autoregressive (AR) random process. An alternating least squares (ALS) method for parameter estimation is presented. We show that in most cases, the ALS method is superior to the modelmismatched ML (M 3 L) method, which ignores the temporal correlation of the interference and noise.
Electro-catalytic activity of carbon based cerium doped lead dioxide anodes was investigated. Ele... more Electro-catalytic activity of carbon based cerium doped lead dioxide anodes was investigated. Electrodes were prepared by electrodepositing lead dioxide on carbon based substrates from a bath comprising 1.0 M lead(II) nitrate and 0.1 M and cerium(III) nitrate. Polarization studies of cerium doped lead dioxide electrodes were carried out using 1.0 mM iso-propanol at scan rate 100 mV/min in a three electrode system as shown in Figure 1. Electro-oxidation of chromium(III) to chromium(VI) was also carried out at the cerium doped lead dioxide electrode (area 30cm2) in a divided cell using 0.3 mM chromium(III) solution. Electrolysis was run for 20 hours and the electrolyte upon analysis by visible spectrophotometry yielded 77.4% conversion of chromium(III) to chromium(VI). Figure 1: Anodic polarization curves: (a) bare carbon, (b) cerium(III)-doped lead dioxide and (c) cerium(III)-doped lead dioxide in 1.0 mM iso-propanol. Background electrolyte: 1.0 M sulphuric acid and E in volts vs. Ag/AgCl,Cl- Reference: J. Kong, S. Shi, L. Kong, X. Zhua and J. Ni, Preparation and characterization of lead dioxide electrodes doped with different rare earth oxides, Electrochim. Acta, 53, 2048 (2007) *Presently at School of Chemistry Monash University Clayton Victoria 3800 Australia
Electrooxidation of p-Chloroaniline at Gold Electrode
ECS Transactions, 2014
Electrochemical oxidation of p-chloroaniline in 0.1 M sodium perchlorate in pure acetonitrile was... more Electrochemical oxidation of p-chloroaniline in 0.1 M sodium perchlorate in pure acetonitrile was studied on gold surface using cyclic and normal pulse voltammetry. Mechanistic interpretation of the voltammetric results is outlined in terms of peak (or half wave) potential dependence on scan rate and concentration of p-chloroaniline.
ABSTRACT Simulation of the cyclic voltammograms of dinitrobutoxy carbonyl fluorenone, t-butyl-2,4... more ABSTRACT Simulation of the cyclic voltammograms of dinitrobutoxy carbonyl fluorenone, t-butyl-2,4,7-trinitrofluorenone, 4-carboxyl-2,5,7-trinitrofluorenone, and 2,4,7-trinitrofluorenone in DMF/tetra-n-butylammonium perchlorate observed (R. O. Loufty et al., Can. J. Chem., 62, (1984) 1877) at mercury bead electrode were simulated by using softwares: CVSIM and ESP 2.4. Two cathodic and two anodic peaks were analysed. ESP took less time. In case of 2-alkyl-4,7-dinitrofluorenone, three anodic and two cathodic experimentally (R. O. Loufty et al., Can. J. Chem., 62, (1984) 1877) reported peaks were analysed by simulation.
Whereas reductive voltammetry of 1-bromopyrrolidin-2,5-dione (N-Bromosuccinimide), or SBr has bee... more Whereas reductive voltammetry of 1-bromopyrrolidin-2,5-dione (N-Bromosuccinimide), or SBr has been extensively studied in non-aqueous systems, relatively few papers have dealt with its electro-reduction in aqueous solutions. This paper describes voltammetry of 1-bromopyrrolidin-2,5-dione at platinum electrode in aqueous nitrate solution.
Voltammetry of N-Bromosuccinimide in Hexafluoropropan-2-ol
ECS Transactions, 2011
Electrochemical behaviour of N-bromosuccinimide (NBS, mp 174 ºC) was investigated in 1,1,1,3,3,3-... more Electrochemical behaviour of N-bromosuccinimide (NBS, mp 174 ºC) was investigated in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) by cyclic and pulsed voltammetry at platinum electrode. The cyclic voltammetric response was characterized by an irreversible reduction peak at around 0.7 V vs. SCE, and an anodic peak at about 0.1 V on reverse sweep. The possible mechanism for electro-reduction of NBS was outlined. In case of normal pulse voltammetry, a well-defined sigmoid-shaped curve was obtained. An increase in step time resulted in a significant cathodic shift. Differential pulse voltammetric response was consistent with the normal pulse behaviour, and featured a single peak centered at about 0.88 V. Linear variation of summit current with pulse height was observed.
The electrochemical oxidation of 4-hydroxybiphenyl was studied at the glassy carbon disk electrod... more The electrochemical oxidation of 4-hydroxybiphenyl was studied at the glassy carbon disk electrode using cyclic, normal pulse and differential pulse voltammetry in a solvent mixture. 4-Hydroxybiphenyl exhibited a well-defined, irreversible peak in 1:1 acetonitrile-water mixture containing 0.2 M sodium perchlorate at glassy carbon (0.125 cm2) electrode. In pulse voltammetry a linear relationship was obtained between the anodic peak current and concentration of 4-hydroxybiphenyl. The work needs optimization for the quantitative determination of 4-hydroxybiphenyl.
In this work electrochemical kinetics of nitrate reduction was investigated on solid cathodes suc... more In this work electrochemical kinetics of nitrate reduction was investigated on solid cathodes such as gold, titanium and aluminum. Enhancement of current density with increase in concentration of nitrate was observed with respect to the background in case of all electrode materials. The apparent electrochemical reaction order (14) for nitrate reduction was evaluated at various cathodes. The reaction order for the electro-reduction of nitrate at titanium showed dependence on electrode potential. Under the similar reactions conditions the electroreduction of nitrobenzene was also studied on the titanium electrode using cyclic voltammetry.
Voltammetry of Vinblastine Sulfate in Acetonitrile
ECS Transactions, 2010
Voltammetry of vinblastine sulfate was carried out in acetonitrile containing 0.2 M of sodium per... more Voltammetry of vinblastine sulfate was carried out in acetonitrile containing 0.2 M of sodium perchlorate. The studies were done when 21.4 mM pyridine was present in the above background solution. Vinblastine sulfate gave a single anodic peak representing irreversible electrochemical oxidation, as shown in both cases. Although, the behavior of vinblastine sulfate was almost comparable in the presence/absence of pyridine. However, the studies carried in the absence of pyridine were more significant.
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