It is reported in this paper a polarographic catalytic double wave of oxygen reduction caused by diphenylamine compounds(diphs).The electrochemical process of the wave includes the polarographic generation of the supe...It is reported in this paper a polarographic catalytic double wave of oxygen reduction caused by diphenylamine compounds(diphs).The electrochemical process of the wave includes the polarographic generation of the superoxide anion O_2^- and the dismutation of O_2^- catalyzed by diphs with redox pseudoreversibility.展开更多
This paper reports a polarographic catalytic wave of lysozyme (LE) in the presence of KIO3. The mechanism of the catalytic wave was discussed. It is illustrated by the catalytic wave of LE that, besides the Brdicka cu...This paper reports a polarographic catalytic wave of lysozyme (LE) in the presence of KIO3. The mechanism of the catalytic wave was discussed. It is illustrated by the catalytic wave of LE that, besides the Brdicka current, there exists a new kind of catalytic wave of protein.展开更多
Polarographic catalytic wave of chlordiazepoxide in the presence of K 2S 2O 8 was studied in aqueous and DMF/H 2O mixed solutions. The results showed that a single reduction wave in alkaline medium was the reducti...Polarographic catalytic wave of chlordiazepoxide in the presence of K 2S 2O 8 was studied in aqueous and DMF/H 2O mixed solutions. The results showed that a single reduction wave in alkaline medium was the reduction of the N=C bond in 1,2 position of chlordiazepoxide via an intermediate free radical in two one electron successive additions. When K 2S 2O 8 was present, the free radical of the N=C bond was oxidized to regenerate the original, producing a parallel catalytic wave of chlordiazepoxide. It was determined that the apparent rate constant k f of the oxidation reaction was 3.2×10 3 mol -1 ·L·s -1 . Using the catalytic wave the trace of chlordiazepoxide can be determined by linear potential scan polarography. In NH 3/NH 4Cl (pH 10.2±0.1, 0.12 mol/L)/K 2S 2O 8 (0.016 mol/L) supporting electrolyte, the second order derivative peak current of the catalytic wave was rectilinear to chlordiazepoxide concentration in the range of 3.20×10 -8 -1.60×10 -7 , 1.60×10 -7 -1.44×10 -6 and 1.44 ×10 -6 -1.44×10 -5 mol/L, respectively. The limit of detection was 9.0×10 -9 mol/L.展开更多
In the present paper, linear sweep polarography (LPS) was employed to study Yb 3+ KMnO 4 system. Results show that this system is characterized as a catalytic wave. The first step of Yb 3+ reduction was th...In the present paper, linear sweep polarography (LPS) was employed to study Yb 3+ KMnO 4 system. Results show that this system is characterized as a catalytic wave. The first step of Yb 3+ reduction was the one electron reduction to Yb 2+ , and improvement in the sensitivity of Yb 3+ was studied. Convolution voltammetry and cyclic voltammetry were employed to determine the rate constant and to confirm the process of electrode. The effects of various parameters, including pH, electrolyte, catalyst concentration and surface active substance on the reduction process were examined.展开更多
文摘It is reported in this paper a polarographic catalytic double wave of oxygen reduction caused by diphenylamine compounds(diphs).The electrochemical process of the wave includes the polarographic generation of the superoxide anion O_2^- and the dismutation of O_2^- catalyzed by diphs with redox pseudoreversibility.
文摘This paper reports a polarographic catalytic wave of lysozyme (LE) in the presence of KIO3. The mechanism of the catalytic wave was discussed. It is illustrated by the catalytic wave of LE that, besides the Brdicka current, there exists a new kind of catalytic wave of protein.
文摘Polarographic catalytic wave of chlordiazepoxide in the presence of K 2S 2O 8 was studied in aqueous and DMF/H 2O mixed solutions. The results showed that a single reduction wave in alkaline medium was the reduction of the N=C bond in 1,2 position of chlordiazepoxide via an intermediate free radical in two one electron successive additions. When K 2S 2O 8 was present, the free radical of the N=C bond was oxidized to regenerate the original, producing a parallel catalytic wave of chlordiazepoxide. It was determined that the apparent rate constant k f of the oxidation reaction was 3.2×10 3 mol -1 ·L·s -1 . Using the catalytic wave the trace of chlordiazepoxide can be determined by linear potential scan polarography. In NH 3/NH 4Cl (pH 10.2±0.1, 0.12 mol/L)/K 2S 2O 8 (0.016 mol/L) supporting electrolyte, the second order derivative peak current of the catalytic wave was rectilinear to chlordiazepoxide concentration in the range of 3.20×10 -8 -1.60×10 -7 , 1.60×10 -7 -1.44×10 -6 and 1.44 ×10 -6 -1.44×10 -5 mol/L, respectively. The limit of detection was 9.0×10 -9 mol/L.
文摘In the present paper, linear sweep polarography (LPS) was employed to study Yb 3+ KMnO 4 system. Results show that this system is characterized as a catalytic wave. The first step of Yb 3+ reduction was the one electron reduction to Yb 2+ , and improvement in the sensitivity of Yb 3+ was studied. Convolution voltammetry and cyclic voltammetry were employed to determine the rate constant and to confirm the process of electrode. The effects of various parameters, including pH, electrolyte, catalyst concentration and surface active substance on the reduction process were examined.
