Differential pulse voltammetric determination of hydroxylamine at an indenedione derivative electrodeposited on a multi-wall carbon nanotube modified glassy carbon electrode

Abstract

A eletrodeposição de filmes finos de um derivado da indenodiona em eletrodo de carbono vítreo modificado por nanotubos de carbono de paredes múltiplas (ECV-NTCPM), mostra um par de picos com características de confinamento em superfície. O eletrodo de carbono vítreo modificado por NTCPM e pela indenodiona (ECV-NTCPMI) apresenta uma alta atividade catalítica para a eletro-oxidação de hidroxilamina. O potencial do pico anódico para a oxidação da hidroxilamina em ECV-NTCPMI é aproximadamente 140 mV, enquanto em ECV-NTCPM e em ECV modificado pela indenodiona (ECV-MI), os potenciais de pico aparecem em aproximadamente 505 e 525 mV, respectivamente. Os resultados mostram que há um aumento da corrente do pico anódico de oxidação da hidroxilamina em ECV-NTCPMI quando comparado ao valor obtido com ECV-MI ou ECV-NTCPM. Os resultados também sugerem que a combinação de NTCPM com um mediador melhora, definitivamente, as características de oxidação da hidroxilamina. Além disso, a voltametria de pulso diferencial exibe dois intervalos dinâmicos lineares de 1,0-10,0 e 10,0-100,0 µmol L -1 com sensitividade de 0,1955 e 0,0841 µA L µmol -1 respectivamente e um limite de detecção mais baixo, de 0,8 µmol L -1 para hidroxilamina. A excelente reversibilidade eletroquímica do par redox, a simplicidade técnica, e a boa atividade eletrocatalítica para hidroxilamina são as vantagens deste eletrodo modificado. Finalmente, a atividade do ECV-NTCPMI foi também investigada para a determinação da hidroxilamina em duas amostras.The electrodeposited thin films of an indenedione derivative on multi-wall carbon nanotubes modified glassy carbon electrode (MWCNT-GCE) shows one pair of peaks with surface confined characteristics. The indenedione MWCNT modified GCE (IMWCNT-GCE) presents a highly catalytic activity toward hydroxylamine electro-oxidation. The anodic peak potential for hydroxylamine oxidation at IMWCNT-GCE is about 140 mV whereas at MWCNT-GCE and indenedione modified GCE (IMGCE), the peak potentials appear at about 505 and 525 mV respectively. The results show that there is an enhancement of the anodic peak current of hydroxylamine oxidation at IMWCNT-GCE as compared to the value obtained at IMGCE or MWCNT-GCE. The results also suggest that a combination of MWCNT and mediator definitely improves the characteristics of hydroxylamine oxidation. Furthermore, differential pulse voltammetry exhibits two linear dynamic ranges of 1.0-10.0 and 10.0-100.0 µmol L -1 with sensitivity of 0.1955 and 0.0841 µA L µmol -1 respectively and a lower detection limit of 0.8 µmol L -1 for hydroxylamine. Excellent electrochemical reversibility of the redox couple, technical simplicity, and good electrocatalytic activity for hydroxylamine are the advantages of this modified electrode. Finally, the activity of IMWCNT-GCE was also investigated for hydroxylamine determination in two natural samples.

Fabrication, characterization and analytical performance of the hydroxylamine sensor based on an oracet blue multi-walled carbon nanotubes film deposited on an electrode surface

“…The calculated apparent diffusion coefficient is in a good agreement with some of those previously reported forhydroxylamine, 32,41,42 but is lower than the values which are reported in some other published papers. 14,40,43 Amperometric studies of electrocatalytic oxidation of hydroxylamine at the OBMWCNT-GCE surface…”

“…Also, a combination of MWCNT and a mediator (OB here) definitely improves the characteristics of hydroxylamine oxidation. Also, the peak potential of hydroxylamine oxidation at the OBMWCNT-GCE is less positive, in most cases, in comparison with those reported for electrodes modified with other mediators such as rutin, 14 nickel hexacyanoferrate, 16 a coumestan derivative, 32 gold nanoparticle-polypyrrole nanowire, 40 an indenedione derivative, 41 chlorogenic acid, 42 4-hydroxy-2-(triphenylphosphonio)phenolate, 43 and ruthenium oxide nanoparticles. 44 The oxidation potentials of hydroxylamine on different modified electrodes are shown in Table 2.…”

“…Figure 4A Table 2, the analytical parameters of electrocatalytic determination of hydroxylamine in this work are compared with the corresponding values previously reported for some other modified electrodes. 10,14,16,32,[40][41][42][43][44] It can be seen that the responses made by the proposed modified electrode are in most cases superior to the previously reported modified electrodes. The average current measured and the precision estimated in terms of relative standard deviation (RSD%) for fifteen repeated measurements (n = 15) of 10.0 µmol L -1 of hydroxylamine at the applied potential of 170 mV on OBMWCNT-GCE were 0.107 ± 0.003 µA and 2.9% respectively.…”

“…The value obtained for j 0 of hydroxylamine at OBMWCNT-GCE is higher than that of the exchange current density at a coumestanderivative modified electrode (0.084 mA cm −2 ) 32 but it is lower than the j 0 value of hydroxylamine at the indenedione modified MWCNT-GCE (16.9 mA cm −2 ). 41 Figure 2B shows that a plot of the catalytic peak current versus the square root of scan rate is linear. This result indicates that, at a sufficient overpotential, the process is diffusion rather than surface-controlled, which is the ideal case for quantitative applications.…”

“…Therefore, various methods have been reported for the determination of low levels of hydroxylamine from industrial, environmental, and health viewpoints. [34][35][36][37][38][39][40][41][42][43][44] These include chromatography, 34,35 spectrophotometric 37 and electrochemical methods. 10,11,14,16,32,[38][39][40][41][42][43][44] In this regard, we had reported the preparation of a rutin multi-walled carbon nanotubes modified glassy carbon electrode (RMWCNT-GCE), 14 a coumestan derivative modified carbon paste electrode, 32 an indenedione derivative MWCNT-GCE (IMWCNT-GCE), 41 a chlorogenic acid MWCNT-GCE (CGA-MWCNT-GCE), 42 a 4-hydroxy-2-(triphenylphosphonio)phenolate MWCNT-GCE (HTP-MWCNT-GCE), 43 a ruthenium oxide nanoparticles, 44 and their applications in hydroxylamine determination.…”