Electrochemical behavior of rhodium acetamidate immobilized on a carbon paste electrode: a hydrazine sensor

Abstract

O comportamento eletroquímico do acetamidato de ródio imobilizado em pasta de carbono e as potencialidades para construção de sensores foram avaliados. O complexo imobilizado mostrou boa estabilidade e propriedades redox, sendo observados dois pares redox reversíveis com potenciais médios entre 0,15 e 0,55 V vs SCE. Entretanto, a resolução dos picos voltamétricos mostrou-se dependente do eletrólito suporte. A correlação entre a capacidade coordenante do eletrólito e seus respectivos potenciais médios sugere que o eletrólito deve coordenar-se em posição axial nos complexos. Além disto, a posição axial deve ser o sítio catalítico, sendo que a oxidação de espécies doadoras, como hidrazina, foi catalisada por estes complexos. O baixo potencial (<300 mV) mostra uma boa viabilidade deste composto para a confecção de sensores para a hidrazina, minimizando problemas de interferentes. Uma boa faixa de resposta linear para a hidrazina foi ajustada pela equação i = 23,13 (± 0,34) c , onde i = corrente em mA and c = concentração em mol dm -3 na faixa de 10 -5 a 10 -2 mol dm -3 . O baixo tempo de resposta (~1 s) poderia ser útil em análises por injeção em fluxo. Este sistema foi bem estável e apresentou boa repetibilidade, mesmo após 30 medições, com uma variância de 0,5 %.The electrochemical behavior of rhodium acetamidate immobilized in carbon paste electrode and the consequences for sensor construction were evaluated. The electrode showed good stability and redox properties. Two reversible redox couples with midpoint potentials between 0.15 and 0.55 V vs SCE were observed. However, peak resolution in voltammetric studies was very dependent on the supporting electrolyte. The correlation between coordinating power of the electrolyte and peak potential suggests that the electrolyte can coordinate through the axial position of the complexes. Furthermore, the axial position may be also the catalytic site, as a catalytical response was observed for hydrazine oxidation. A good linear response range for hydrazine was fit by the equation i = 23.13 (± 0.34) c , where i = current in mA and c = concentration in mol dm -3 in the range of 10 -5 up to 10 -2 mol dm -3 . The low applied potential (<300 mV) indicates a good device for hydrazine sensor, minimizing interference problems. The short response time (~1 s) may be useful in flow injection analysis. Furthermore, this system was very stable presenting good repeatability even after 30 measurements with a variance of 0.5 %.

Fabrication, electrochemical characteristics and electrocatalytic activity of 4-((2-hydroxyphenylimino)methyl)benzene-1,2-diol electrodeposited on a carbon nanotube modified glassy carbon electrode as a hydrazine sensor

“…In Table 3, some of the electroanalytical parameters obtained in this research are compared with those previously reported by others. [1][2][3][4]7,9,12,[14][15][16][17][18][47][48][49][50][51][52][53][54][55] A comparison of the analytical parameters of hydrazine determination at various modified electrode surfaces shows that the proposed modified electrode has advantages such as wide linear dynamic range (4.0-750.4 mM) and good detection limit (1.1 mM) for hydrazine determination.…”

Electrode Materials (Bulk Materials and Modification)

“…Some Schiff base complexes were also used for similar purposes. 817,818 Finally, other organometallic electrocatalysts have been reported as CPE modifiers, such as rhodium acetamide, 819 iron(II)-nitroprusside, 820 or Co(II)-1-alkyl-1H-benzo [d] 1-3 triazole derivatives 821 for sensing of some pollutants.…”

Electrochemical Studies of a New Iron Porphyrin Entrapped in a Propylpyridiniumsilsesquioxane Polymer Immobilized on a SiO2/Al2O3 Surface

“…Studies made in solutions having different pH showed that the intensity of the current peak densities was sensitive to the pH change as illustrated in Figure 5 with the efficiency increasing at higher pH values. This behavior is attributed to the lower affinity of the protonated hydrazine at low solution pH for the metallic center of the porphyrin [38,39].…”