Th(IV)-hexacyanoferrate modified carbon paste electrode as a new electrocatalytic probe for simultaneous determination of ascorbic acid and dopamine from acidic media

Abstract

A estabilidade do eletrodo de pasta de carbono (CPE) foi obtida com o par eletrônico do Th(IV)-hexaferrocianeto (Th-HCF) e seu comportamento eletroquímico foi investigada por voltametria cíclica. A constante aparente do meio heterogêneo (ks) e o coeficiente de transferência( ), do par eletrônico Th-HCF e CPE, foram calculados como 0,47 e 3,1 ± 0,1 s -1 , respectivamente. A cobertura da superfície ( ) do presente eletrodo foi calculada como 7,06 × 10 -10 mol cm -2 . O Th-HCF modificado com o eletrodo de pasta de carbono (THMCPE) apresentou um bom comportamento eletrocatalítico, com uma mudança significativa nos valores negativos do potenciais de oxidação do ácido ascórbico (AA) e da dopamina (DA), em meio ácido (solução tampão fosfato, pH 3). O THMCPE mostrou também excelentes características para a determinação simultânea de AA e DA. As curvas amperométricas utilizando o presente catalisador são lineares para a DA e AA , na faixa de concentrações entre 8 ×

Study on the structural and electrocatalytic properties of Ba2+- and Eu3+-doped silica xerogels as sensory platforms

“…The development of electrocatalytic devices has been an area that has seen great advancement in recent years [1][2][3][4][5][6][7][8][9][10] due to their low cost of instrumentation and the possibility of being assembled by different materials, [1][2][3][4][5][6][7][8][9][10][11][12] with several reviews found in the literature. 11,[13][14][15] Furthermore, by adding different chemical species to the electrode surface, electron transfer in slow electrochemical reactions is facilitated 9 as the physicochemical nature of the electrode/solution interface is changed.…”

“…9 Electrocatalytic devices based on CPE have been widely applied toward the determination of trace amounts of elements, the evaluation of electrochemical processes, the preparation of biosensors, and the investigation of electrocatalytic mechanisms and organic species. [1][2][3][4][5][6][7][8][9][10] Lanthanides are very versatile and can be used in the production of glasses, ceramics, 17 alloys, and electronics, and they also nd application in agriculture and natural sciences. 18 Lanthanide luminescent-based chemical and biological sensors have been highlighted due to their photophysical properties and their selective emission response to specic analytes.…”

“…18 Lanthanide luminescent-based chemical and biological sensors have been highlighted due to their photophysical properties and their selective emission response to specic analytes. [19][20][21][22][23] Despite the huge and increasing number of applications using rare earth ions, proportionally there are few studies related to the development and use of rare earth-based electrocatalysts for sensors; 3,11,[24][25][26][27][28][29][30][31][32][33][34] nonetheless, this application should be explored due to the excellent catalytic behavior that lanthanides exhibit. Silica xerogels obtained from the sol-gel method have been the focus of attention for electrochemists because of their advantageous features, such as mechanical stability, durability, and the possibility of doping them with metal cations.…”

Signal amplification of dopamine using lanthanum hexacyanoferrate-modified electrode

“…[23][24][25][26][27][28][29][30] The conducting polymer incorporated metal hexacyanoferrates show poor selectivity towards DA determination. 31,32 Cobalt hexacyanoferrate-modified electrodes, 13,14,33 Th(IV)-hexacyanoferrate-modified electrodes 34 and ruthenium hexacyanoferrate-modified electrodes 35 were used to study the high concentrations of DA. Besides, nickel hexacyanoferrate, 36,37 silver hexacyanoferrate 38 and tin hexacyanoferrate-modified 39 electrodes were studied at slightly higher concentrations of DA.…”

SiO2/MPc/C e electrically conductive ceramic material (Pc: phthalocyanine, M=Mn(II), Co(II), Cu(II)) a new substrate for the preparation of electrochemical sensors and biosensors

“…A comparison of the analytical parameters for dopamine with those previously reported for other biomimetic systems, [140][141][142][143][144] under similar experimental conditions, is presented in Table 3.6. A low detection limit and a high sensitivity are observed, even when compared to biosensors based on peroxidase or tyrosinase enzymes 145,146 for phenol determinations.…”