Carbon Paste Electrode Incorporating 1‐[4‐(Ferrocenyl Ethynyl) Phenyl]‐1‐Ethanone for Electrocatalytic and Voltammetric Determination of Tryptophan

Raoof, Jahan Bakhsh; Ojani, Reza; Karimi-Maleh, Hassan

doi:10.1002/elan.200704176

Cited by 144 publications

(69 citation statements)

References 15 publications

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“…In addition, the value of α was calculated for the oxidation of CA at pH 7.0 for the MWCNTPE in both the absence and presence of mediator using the following equation, 34,35 αn α = 0.048/(E P -E P/2 )…”

Section: Catalytic Effectmentioning

confidence: 99%

Electrocatalytic determination of cysteamine using multiwall carbon nanotube paste electrode in the presence of 3,4-dihydroxycinnamic acid as a homogeneous mediator

Keyvanfard¹,

Sami²,

Karimi-Maleh³

et al. 2013

J. Braz. Chem. Soc.

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A eletrooxidação da cisteamina (CA) foi estudada por eletrodos de pasta de nanotubos de carbono modificados com ácido 3,4-diidroxicinâmico (3,4-DHCA) usando voltametria cíclica, cronoamperometria e voltametria de varredura linear. Usando o eletrodo modificado, a cinética de eletrooxidação da CA foi consideravelmente intensificada através da redução do potencial anódico por meio de uma reação catalítica. O mecanismo de comportamento eletroquímico da CA na superfície do eletrodo modificado foi analisado por vários métodos eletroquímicos, na presença de mediador. O eletrodo modificado preparado apresentou respostas voltamétricas com alta sensibilidade para CA, o que o torna muito adequado para a detecção de CA em quantidades de traço. Um intervalo dinâmico linear de 0,25-400 µmol L −1 para a CA foi obtida em solução tamponada com pH 7,0. O limite de detecção foi de 0,09 µmol L −1 .The electrooxidation of cysteamine (CA) was studied by modified carbon nanotubes paste electrode in the presence of 3,4-dihydroxycinnamic acid (3,4-DHCA) using cyclic voltammetry, chronoamperometry and linear sweep voltammetry. Using the modified electrode, the kinetics of CA electrooxidation was considerably enhanced by lowering the anodic over-potential through a catalytic fashion. The mechanism of CA electrochemical behavior at the modified electrode surface was analyzed by various electrochemical methods in the presence of mediator. The prepared modified electrode showed voltammetric responses with high sensitivity for CA, making it very suitable for the detection of CA at trace levels. A linear dynamic range of 0.25-400 µmol L −1 for CA was obtained in buffered solutions with pH 7.0. The limit of detection was 0.09 µmol L −1 . Keywords: cysteamine, electrocatalysis, voltammetry, multiwall carbon nanotubes, 3,4-dihydroxycinnamic acid IntroductionCysteamine is an important thiol drug for the treatment of cystinosis.1 The deficiency of a cystine carrier in the lysosomal membrane leads to cystine accumulation within the lysosomes, ultimately crystallizing in vital organs such as the liver, kidney, spleen, intestines, and cornea.2,3 A number of long term clinical trials have shown that cysteamine administration (as cysteamine hydrochloride) stabilizes renal function, delays glomerular deterioration and improves linear growth. 4 Cysteamine and its disulfide, cystamine, have been shown to be neuroprotective in a number of cell culture and animal models.5 With this goal in mind, a rapid but specific and sufficiently sensitive analytical method was required for total cysteamine determination in biological and pharmaceutical samples. Numerous methods have been reported for the determination of CA in pharmaceutical and biological samples including chromatography, 6-8 electrophoresis, 9 gas chromatography with flame photometric detection, 10 ion exchange chromatography, 11 and electrochemical methods 12-14 using modified electrodes. Due to problems in chromatographic methods such as selecting a suitable column or a mobile phase with liquid chrom...

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Section: Catalytic Effectmentioning

confidence: 99%

Electrocatalytic determination of cysteamine using multiwall carbon nanotube paste electrode in the presence of 3,4-dihydroxycinnamic acid as a homogeneous mediator

Keyvanfard¹,

Sami²,

Karimi-Maleh³

et al. 2013

J. Braz. Chem. Soc.

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“…A linear response was obtained in the concentration range 1-5.9 × 10 −5 M as well as 2-8 × 10 −3 M. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.4 × 10 −5 M and 2.29 × 10 −5 M respectively for the lower end calibration graph. Modified CPE showed the linear range and detection limit comparable [25,26] and better [51][52][53] than the reported electrochemical methods.…”

Section: Discussionmentioning

confidence: 80%

Synthesis and characterization of cobalt nitroprusside nano particles: Application to sulfite sensing in food and water samples

Devaramani

Malingappa

2012

Electrochimica Acta

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a b s t r a c tA new protocol toward the synthesis of cobalt nitroprusside (CoNP) coordination nanoparticles has been described based on drop-by-drop (DbD) method without using any additives. It was also prepared by sonication as well as bulk mixing methods for comparison purpose. The prepared complex was characterized by Infrared spectroscopy (FTIR), XRD and cyclicvoltammetry (CV) techniques. The CoNP complexes prepared by different synthetic approaches were used as modifier molecules to fabricate carbon paste electrodes (CPE's) toward electrochemical oxidation of sulfite. The experimental results revealed that the cobalt nitroprusside nanoparticles (n-CoNP) prepared by drop-by-drop method showed a considerable enhancement in the electrocatalytic activity when compared to its counterparts prepared by other approaches. Electrochemical behavior of the n-CoNP CPE was studied and used as an electrochemical sensor for the quantification of sulfite at trace level. It showed a linear response over the concentration range 1-5.9 × 10 −5 M and 2-8 × 10 −3 M of sulfite. The limit of detection and limit of quantification were found to be 0.4 × 10 −5 M and 2.29 × 10 −5 M respectively. The interference of various organic acids and inorganic ions commonly present in different food and water sample matrices were studied. The n-CoNP modified electrode was used for the quantification of sulfite in different food samples and the results were in good agreement with those obtained by the standard iodometric protocol.

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“…This method has been used for estimating the value of k h for some compounds. [20][21][22][23] The effect of solution pH on electrochemical responses of benserazide and/or levodopa at the surface of CAMCPE was investigated over a pH range of 6.5 to 10.5 using cyclic voltammetry. Figure 6 shows the variation in ΔI pa versus pH.…”

Section: Influence Of Variablesmentioning

confidence: 99%

Sequential determination of benserazide and levodopa by voltammetric method using chloranil as a mediator

Ensafi¹,

Arabzadeh²,

Karimi-Maleh³

2010

J. Braz. Chem. Soc.

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Descrevemos um método eletroquímico para a determinação voltamétrica seqüencial de benserazida e levodopa usando cloroanil (CA) como eletro-catalisador. Para investigar a adequação do CA como mediador na oxidação eletrocatalitica da benserazida e levodopa, em solução aquosa, foram usadas a voltametria cíclica, voltametria de pulso diferencial, cronoamperometria e espectroscopia de impedância eletroquímica (EIE). A oxidação da levodopa e da benserazida ocorrem, respectivamente, em potenciais aproximadamente 230 e 480 mV menos positivos do que com o eletrodo de pasta de carbono não modificado usado. Sob condições ótimas, a corrente de pico da oxidação eletrocatalítica da levodopa e benserazida mostraram dois intervalos dinâmicos lineares com limite de detecção de 0,65 µmol L -1 e 0,95 µmol L -1 , respectivamente. O desvio padrão relativo para a determinação de 5,0 × 10 -5 mol L -1 de benserazida e 5,0 × 10 -4 mol L -1 de levodopa foram 2,0 e 2,0% (n = 5), respectivamente. Os intervalos de calibração lineares foram 1,0-500 µmol L -1 para benserazida e 3-500 µmol L -1 para levodopa usando voltametria de pulso diferencial. O método proposto foi testado com sucesso na determinação da levodopa e benserazida em amostras de urina, demonstrando boa aplicabilidade e confiabilidade. An electrochemical method is described for the sequential voltammetric determination of benserazide and levodopa using chloranil (CA) as an electrocatalyst. Cyclic voltammetry, differential pulse voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS) were used to investigate the suitability of CA as a mediator for the electrocatalytic oxidation of benserazide and levodopa in an aqueous solution. The oxidation peak potential of levodopa and benserazide shifted at about 230 and 480 mV to a less positive potential, respectively, than with the unmodified carbon paste electrode. Under optimum conditions, the electrocatalytic oxidation peak current of levodopa and benserazide showed two linear dynamic ranges with limit of detection of 0.65 µmol L -1 and 0.95 µmol L -1 , respectively. The relative standard deviations for the determination of 5.0 × 10 -5 mol L -1 benserazide and 5.0 × 10 -4 mol L -1 levodopa were 2.0 and 2.0% (n = 5), respectively. The linear calibration ranges were 1.0-500 µmol L -1 for benserazide and 3-500 µmol L -1 for levodopa using differential pulse voltammetry. The proposed method has been successfully applied for the determination of levodopa and benserazide in urine samples, demonstrating the feasibility and reliability of the proposed method.

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Carbon Paste Electrode Incorporating 1‐[4‐(Ferrocenyl Ethynyl) Phenyl]‐1‐Ethanone for Electrocatalytic and Voltammetric Determination of Tryptophan

Cited by 144 publications

References 15 publications

Electrocatalytic determination of cysteamine using multiwall carbon nanotube paste electrode in the presence of 3,4-dihydroxycinnamic acid as a homogeneous mediator

Electrocatalytic determination of cysteamine using multiwall carbon nanotube paste electrode in the presence of 3,4-dihydroxycinnamic acid as a homogeneous mediator

Synthesis and characterization of cobalt nitroprusside nano particles: Application to sulfite sensing in food and water samples

Sequential determination of benserazide and levodopa by voltammetric method using chloranil as a mediator

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