摘要
目的 研究在过氧化氢存在下橙皮苷极谱催化波产生机理 ,建立测定橙皮苷的极谱催化波新方法。方法用线性变位极谱法、循环伏安法等技术。结果 橙皮苷C 4位上的羰基CO首先经单电子单质子还原为自由基 ,产生第 1个还原波 ;该自由基的一部分由于共轭作用使其能量降低 ,并进一步还原 ,产生第 2个还原波 ,另一部分发生二聚化反应。当氧化剂H2 O2 存在时 ,H2 O2 氧化橙皮苷羰基还原中间体自由基 ,阻断了该自由基进一步还原和二聚化反应 ,并使橙皮苷再生 ,产生橙皮苷的极谱催化波。在 0 12mol·L- 1 HAc 0 4 0mol·L- 1 NaAc (pH 5 3 ) 1 0× 10 - 2mol·L- 1 H2 O2 支持电解质中 ,该催化波的一阶导数峰电流与橙皮苷浓度在 1 0× 10 - 7- 1 8× 10 - 6 mol·L- 1 有良好线性关系 ,相关系数γ =0 995 4。检测限为 8 0× 10 - 8mol·L- 1 。结论 该催化波有较高的灵敏度 ,可用于药物分析。
AIM To study the mechanism of a polarographic catalytic wave of hesperidin in the presence of hydrogen peroxide, and to propose a new catalytic wave method for the determination of hesperidin. METHODS Linear-potential scan polarography, cyclic voltammetry and DC polarography were used in this work. RESULTS In 0 12 mol·L -1 HAc-0 40 mol·L -1 NaAc (pH 5 3) supporting electrolyte, the carbonyl group CO of hesperidin at the C-4 position yielded two reduction waves. The carbonyl group CO firstly undergoes a 1 e, 1H + reduction to form an intermediate free radical, producing the first reduction wave with peak potential -1 35 V ( vs SCE). Further reduction of the radical was simultaneous with its dimerization. A part of the radical was further reduced, producing the second reduction wave with peak potential -1 70 V ( vs SCE). Other part of the free radical was dimerized. The dimer could be oxidized at -1 17 V ( vs SCE). When oxidant H 2O 2 was present, both the further reduction and dimerization were interrupted, and a polarographic catalytic wave was produced because H 2O 2 oxidized the intermediate free radical to regenerate the original CO group. Based on the polarographic catalytic wave, a new method for the determination of hesperidin was proposed. 0 12 mol·L -1 HAc-0 40 mol·L -1 NaAc (pH 5 3)-1 0×10 -2 mol·L -1 H 2O 2 solution was chosen as supporting electrolyte. The first-order derivative technique was used to eliminate the higher background current from H 2O 2 reduction and to well separate the catalytic wave from H 2O 2 reduction wave. The first-order derivative peak current of the catalytic wave is proportional to hesperidin concentration in the range of 1 0×10 -7 -1 8×10 -6 mol·L -1 with correlation coefficient γ=0 9954. The limit of detection was 8 0×10 -8 mol·L -1 . The sensitivity of the catalytic wave was higher by one order of magnitude than other electrochemical methods based on reduction wave previously reported. CONCLUSION The catalytic wave method has higher sensitivity and can be used for pharmaceutical analysis.
出处
《药学学报》
CAS
CSCD
北大核心
2001年第11期844-848,共5页
Acta Pharmaceutica Sinica
基金
国家自然科学基金资助项目 ( 2 9875 0 17)
关键词
橙皮苷
过氧化氢
极谱催化波
自由基
药物分析
hesperidin
hydrogen peroxide
polarographic catalytic wave
free radical
