Sensitivity of Electrochemically Nanostructured Carbon Fiber Ultramicroelectrodes in the Determination of Adenosine

El-Nour, Kholoud Abou; Brajter-Toth, Anna

doi:10.1002/1521-4109(200007)12:11<805::aid-elan805>3.0.co;2-x

Cited by 22 publications

(19 citation statements)

References 21 publications

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“…After curing, the tip of the electrode was sanded off in a polishing wheel (Arotec, Brazil) using 600-grit silicon carbide paper (Arotec, Brazil), and finally the surface was gently polished in the polishing wheel with 0.1 mm particle size g-alumina suspension (Arotec, Brazil). Before use, the polished electrodes were sonicated 37,38 in isopropyl alcohol and in doubly distilled water during 5 min in each solvent. The response of the polished electrodes was tested by cyclic voltammetry with 5.0 mmol L -1 potassium ferricyanide in 0.5 mol L -1 KCl solution at 50 mV s -1 .…”

Section: Electrodesmentioning

confidence: 99%

Caffeine determination at a carbon fiber ultramicroelectrodes by fast-scan cyclic voltammetry

Nunes¹,

Cavalheiro²

2012

J. Braz. Chem. Soc.

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A possibilidade de determinação eletroanalítica de cafeína com ultramicroeletrodo de fibra de carbono (CF-UME), utilizando voltametria de varredura rápida, foi avaliada. Os CF-UMEs foram submetidos a pré-tratamentos eletroquímicos. Parâmetros como o número de ciclos para cálculo da média, velocidade de varredura, intervalo de potencial e o tipo de pré-tratamento superficial foram otimizados. Sob condições otimizadas, foi possível alcançar intervalo linear de resposta entre 10,0 e 200 mmol L-1 , obtendo limites de detecção de 3,33 mmol L-1. O método foi aplicado à determinação de cafeína em amostras comerciais de fármacos, com erros entre 1,0 e 3,5% em relação ao valor do rótulo e valores de adição e recuperação de 97-114%. Caffeine determination using a fast-scan voltammetric procedure at a carbon fiber ultramicroelectrode (CF-UME) is described. The CF-UME was submitted to electrochemical pretreatment. Parameters such as number of acquisition cycles, scan rate, potential window, and the electrochemical surface pretreatment were optimized. Using the optimized conditions, it was possible to achieve a LDR from 10.0 up to 200 mmol L-1 , with a LOD of 3.33 mmol L-1. The method has been applied in the determination of caffeine in commercial samples, with errors of 1.0-3.5% in relation to the label values and recoveries of 97-114% within the linear range.

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Section: Electrodesmentioning

confidence: 99%

Caffeine determination at a carbon fiber ultramicroelectrodes by fast-scan cyclic voltammetry

Nunes¹,

Cavalheiro²

2012

J. Braz. Chem. Soc.

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“…El-Nour prepared a highly active carbon fiber ultramicroelectrode (CFE) as sensor in the sensitive determination of adenosine under physiological conditions. 15 Oliveira-Brett used a carbon fiber microelectrode for the investigation on the electrooxidation mechanism of guanine and adenine. 16 The reduced capacitive contribution of microelectrodes makes it possible to study the electron transfer (ET) reactions of these processes by means of fast scan rate cyclic voltammetry and to establish a more sensitive detection method by differential pulse voltammetry.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Oxidation of 2’-deoxyguanosine-5’-triphosphate on Ionic Liquid Modified Carbon Paste Microelectrode and its Sensitive Detection

Gao¹,

Duan²,

Xu³

et al. 2011

Croat. Chem. Acta

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Abstract. Electrochemical oxidation of 2'-deoxyguanosine-5'-triphosphate (dGTP) was investigated on the ionic liquid modified carbon paste microelectrode by cyclic voltammetry in this paper. The carbon ionic liquid microelectrode (mCILE) was prepared with ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtOSO 3 ]) as the modifier. Then the electrochemical process of dGTP on the mCILE was recorded with the electrochemical parameters calculated and the oxidation mechanism discussed. Under the optimal conditions differential pulse voltammetric peak current was proportional to the dGTP concentration in the range from 1.0× 10 -6 M to 7.0× 10 -4 M with the linear regression equation as log ( I pa / A) = 0.77 log(c / mol dm -3 ) -4.082 (γ = 0.999). The proposed method showed good selectivity and stability without the interferences of coexisting substances.

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“…The new method of FSV determinations of adenosine at the new CFEs is sensitive. 12,13 It has been postulated that the CFE surface nanostructure, of the CFEs that were fabricated by the new procedure, produced during the ECP of the electrode and maintained by the method of FSV signal acquisition, contributes to the high sensitivity in the determinations of adenosine. 12 High sensitivity is important in the determination of adenosine in biological samples because of the transient nature of the adenosine signal, which reaches micromolar concentrations during physiological stress.…”

Section: Introductionmentioning

confidence: 99%

Development of adenosine sensor: effect of physiological buffers on activity and sensitivity in adenosine determinations by fast scan voltammetry

El-Nour

Brajter-Toth

2003

Analyst

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A new fast scan voltammetry (FSV) method was tested in the determinations of adenosine in physiological buffers at pH 7.4. The buffers can be used in the determinations of adenosine in vivo and include 7 x 10(-2) M phosphate, Krebs-Henseleit (K-H) and Hanks' Balanced Salts (HBSS). A new method of fabrication of carbon fiber electrodes (CFEs) by polishing, followed by electrochemical pretreatment (ECP) was developed for the determination. After the ECP of CFE, CFE background current was stable in FSV determinations even though an increase in the background current was observed after the ECP in the buffers at pH 7.4. The sensitivity in FSV determinations of adenosine at the pretreated electrodes was tested in the physiological buffers at the potential scan rate of 500 V s(-1) at pH 7.4. Buffer composition and pH was the same during the ECP of CFE and in the FSV determinations. The sensitivity in the FSV determinations of adenosine at the new CFEs was high, compared to that previously reported at CFEs prepared by other methods, and showed a limited dependence on buffer composition. However, a small increase in buffer pH above 7.4 resulted in a decrease in sensitivity in the determinations of adenosine. The decrease in sensitivity was associated with an additional increase in CFE background current at pH > 7.4. At pH 7.4 best sensitivity and limit of detection was obtained in 7 x 10(-2) M phosphate buffer, where the background current was lowest. The sensitivity was half that in K-H and HBSS. Standard deviation of measurements was ca. 1%. The results demonstrate the feasibility of sensitive FSV determinations of adenosine in physiological buffers at pH 7.4 at CFEs.

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Sensitivity of Electrochemically Nanostructured Carbon Fiber Ultramicroelectrodes in the Determination of Adenosine

Cited by 22 publications

References 21 publications

Caffeine determination at a carbon fiber ultramicroelectrodes by fast-scan cyclic voltammetry

Caffeine determination at a carbon fiber ultramicroelectrodes by fast-scan cyclic voltammetry

Electrochemical Oxidation of 2’-deoxyguanosine-5’-triphosphate on Ionic Liquid Modified Carbon Paste Microelectrode and its Sensitive Detection

Development of adenosine sensor: effect of physiological buffers on activity and sensitivity in adenosine determinations by fast scan voltammetry

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