Electroless deposition of bis(4'-(4-Pyridyl)-2,2':6',2''-terpyridine)iron(II) thiocyanate complex onto carbon nanotubes modified glassy carbon electrode: application to simultaneous determination of ascorbic acid, dopamine and uric acid

Abstract

Um eletrodo de carbono vítreo modificado por nanotubos de carbono de paredes múltiplas (NTCPM) e pelo complexo tiocianato de bis(piterpi) ferro(II) (piterpi = 4'-(4-piridil)-2,2':6',2"-terpiridina) foi investigado através de métodos voltamétricos em solução de tampão acetato (pH 5). A performance do eletrodo modificado pelo complexo de ferro(II)/NTCPM foi avaliada por voltametria de pulso diferencial e microscopia eletrônica de varredura (MEV). O eletrodo de carbono vítreo modificado apresentou uma excelente resposta eletroquímica para ácido ascórbico (AA), dopamina (DA) e ácido úrico (AU). Os picos de oxidação em voltametria de pulso diferencial para AA e DA, DA e AU, AA e AU são separados por 210, 136 e 346 mV, respectivamente. Esta separação permite a determinação simultânea de AA, DA e AU. As correntes de pico anódico para AA, DA e AU aumentam linearmente com a concentração na faixa 1,10×10, respectivamente, com um coeficiente de correlação (r) sempre maior do que 0.998. Além disto, o eletrodo modificado também apresentou boa sensibilidade e estabilidade. Resultados satisfatórios foram alcançados para a determinação de AA em tabletes de vitamina C, DA em solução de dopamina de injeção, e AU em amostras de sangue humano.A glassy carbon (GC) electrode modified by multi-walled carbon nanotubes (MWNTs) and bis(pyterpy)iron(II) thiocyanate complex (pyterpy = 4'-(4-pyridyl)-2,2':6',2''-terpyridine) was investigated by voltammetric methods in acetate buffer solution (pH 5). Performances of the iron(II)-complex/MWNTs modified electrode were evaluated with differential pulse voltammetry and scanning electron microscopy (SEM). The modified glassy carbon electrode shows an excellent electrochemical response for ascorbic acid (AA), dopamine (DA) and uric acid (UA). The differential pulse voltammetry oxidation peaks for AA and DA, DA and UA, AA and UA are separated by 210, 136 and 346 mV, respectively. This separation permits the simultaneous determination of AA, DA and UA. The anodic peak currents of AA, DA and UA increase linearly with concentration in the range of 1.10×10 , respectively, with a correlation coefficient (r) always higher than 0.998. In addition, the modified electrode also shows good sensitivity and stability. Satisfactory results were achieved for the determination of AA in vitamin C tablets, DA in dopamine injection solution and UA in human blood serum samples.

Amperometric Sensing Based on Glutathione Protected Au25 Nanoparticles and Their pH Dependent Electrocatalytic Activity

“…The detection limit (3 s/m) and sensitivity (m) were found to be 0.31 mM and 23.9 nA/mM for AA and 0.35 mM and 21.6 nA/mM for DA, respectively, where s corresponds to the blank standard deviation and m to the slope of the calibration graph. The observed linear range, sensitivity and detection limit are comparable with the recently reported sensors for the determination of these analytes [30][31][32][33].…”

Multi-walled carbon nanotubes doped with boron as an electrode material for electrochemical studies on dopamine, uric acid, and ascorbic acid

“…B-MWCNTs appear to be more sensitive compared to other materials reported in literature and thus it can be considered as promising material for future applications in electrochemical sensing. [31] c Nitrogen-doped MWCNTs [34] d Nitrogen-doped MWCNTs [30] e Pristine MWCNTs [34] f MWCNTs modified with iron(II) thiocyanate complex [35] …”

“…In addition, the limits of detection of pristine MWCNTs, P-MWCNTs, BMWCNTs, and N-MWCNTs towards oxidation of DA and UA are presented graphically in histograms in Fig. S14 (ESM) [30,31,34,35]. Furthermore, a comprehensive comparison of detection limits of B-MWCNTs and other composite films reported in literature towards oxidation of DA, UA, and AA is shown in Table S3 (ESM).…”

Microelectronics-Based Biosensors Dedicated to the Detection of Neurotransmitters: A Review

“…The UA and AA interference was overcome by applying a specific potential region, using MWNT/EPPGE for the determination of catecholamines and, thus, preventing UA and AA from interfering with the determination. Kamyabi et al similarly reported the electrochemical behavior of AA, DA and UA on the surface of the iron (II) complex-MWNT-modified GC electrode [ 79 ]. The modified electrode showed sensitivity, selectivity and anti-fouling properties.…”