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

Abstract

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.

Application of ionic liquid–TiO2 nanoparticle modified carbon paste electrode for the voltammetric determination of benserazide in biological samples

“…Standard addition method was used for calculating the benserazide concentration. The proposed method was also compared with a published method [35] for checking the accuracy of the results. The results are given in Table 3 indicating that the modified electrode retained its efficiency for the determination of benserazide and tryptophan in real samples with satisfactory results.…”

Voltammetric Detection of Levodopa and Benserazide at Polypyrrole and Single Walled Carbon Nanotube Based Electrode

“…Techniques such as chromatography (Adamiak-Giera and Gawronska-Szklarz, 2018;Loutelier-Bourhis et al, 2004;Martins et al, 2013), spectrophotometry (Uslu and Özkan, 2002), chemiluminescence (He et al, 2006) and voltammetry (Miraki et al, 2019;Ensafi et al, 2010) have also been used in the analysis of benserazide and levodopa binary drug mixture. The common feature of these substances is that they have a monoamine neurotransmitter substance structure that does not contain chromophore groups.…”

Highly Sensitive Levodopa Determination by Means of Adsorptive Stripping Voltammetry on Ruthenium Dioxide-Carbon Black-Nafion Modified Glassy Carbon Electrode

“…The use of fluorescence spectrometry [ 7 ] and spectrophotometry [ 8 ] was also reported. Voltammetry which belongs to the group of electrochemical methods is also a useful tool for Levodopa determination [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. In comparison to the mentioned methods, voltammetry has many advantages.…”