The electrochemical behavior of the degradation product of cefdinir（CDR） was studied in a 0.05 mol/L NaOH solution by means of linear sweep voltammetry（LSV） and cyclic voltammetry（CV）. The results indicate that ...The electrochemical behavior of the degradation product of cefdinir（CDR） was studied in a 0.05 mol/L NaOH solution by means of linear sweep voltammetry（LSV） and cyclic voltammetry（CV）. The results indicate that the C=N bond in the oxime group was reduced. Moreover, a saturated adsorption amount of 1.32× 10^-10 mol/cm2 at Hg electrode was obtained. The adsorption coefficient β was 1.56× 10^5 L/mol. Gibbs standard energy of adsorption AGO at 25 ℃ was -29.63 kJ/mol and the number of electrons transferred n was 2. A method for the determination of CDR was proposed by differential pulse voltammetry（DPV）. The reduction peak currents of the CDR＇s degradation product were found to be linear in a concentration range of 4.0×10^-7--4.0×10^- 6 mol/L and that of 4.0× 10^-8-4.0× 10^-7 mol/L, respectively. The detection limit was found to be 3.0× 10^-8 mol/L under the optimized conditions. The applica- bility of this approach was illustrated by the determination of CDR in capsules. In addition, the mechanism about the degradation of CDR in 0.2 mol/L NaOH was discussed by UV spectrophotometry.展开更多
The water soluble tetra p sulfonatophenylporphyrinatolanthanide, [Ln·TPPS·OH ·2imidazole] ·3H 2O(Ln=Tb～Yb), were synthesized and characterized. Their stability and complex constants were...The water soluble tetra p sulfonatophenylporphyrinatolanthanide, [Ln·TPPS·OH ·2imidazole] ·3H 2O(Ln=Tb～Yb), were synthesized and characterized. Their stability and complex constants were also studied and determined. The structural formula of the lanthanide porphyrins was proposed too. The lanthanide atom is sitting above the porphyrin plane. For the lanthanide porphyrin complexes, the complex becomes more stable and the reduction potential has a slight shift to more positive values as the atomic number increases from Tb to Yb. The mechanism of electrode processes for these lanthanidee porphyrin complexes were investigated in details.展开更多
基金Supported by the Natural Science Foundation of Shaanxi Province in China(No.2005B28)
文摘The electrochemical behavior of the degradation product of cefdinir（CDR） was studied in a 0.05 mol/L NaOH solution by means of linear sweep voltammetry（LSV） and cyclic voltammetry（CV）. The results indicate that the C=N bond in the oxime group was reduced. Moreover, a saturated adsorption amount of 1.32× 10^-10 mol/cm2 at Hg electrode was obtained. The adsorption coefficient β was 1.56× 10^5 L/mol. Gibbs standard energy of adsorption AGO at 25 ℃ was -29.63 kJ/mol and the number of electrons transferred n was 2. A method for the determination of CDR was proposed by differential pulse voltammetry（DPV）. The reduction peak currents of the CDR＇s degradation product were found to be linear in a concentration range of 4.0×10^-7--4.0×10^- 6 mol/L and that of 4.0× 10^-8-4.0× 10^-7 mol/L, respectively. The detection limit was found to be 3.0× 10^-8 mol/L under the optimized conditions. The applica- bility of this approach was illustrated by the determination of CDR in capsules. In addition, the mechanism about the degradation of CDR in 0.2 mol/L NaOH was discussed by UV spectrophotometry.
文摘The water soluble tetra p sulfonatophenylporphyrinatolanthanide, [Ln·TPPS·OH ·2imidazole] ·3H 2O(Ln=Tb～Yb), were synthesized and characterized. Their stability and complex constants were also studied and determined. The structural formula of the lanthanide porphyrins was proposed too. The lanthanide atom is sitting above the porphyrin plane. For the lanthanide porphyrin complexes, the complex becomes more stable and the reduction potential has a slight shift to more positive values as the atomic number increases from Tb to Yb. The mechanism of electrode processes for these lanthanidee porphyrin complexes were investigated in details.
