摘要
在0.25mol·L-1KH2PO4-NaH2PO4(pH6.38)底液中,盐酸洛美沙星(Lomenfloxacin,简称LF)在汞电极上有一线性扫描还原峰,峰电位EP=-1.24V(vsAg/AgCl),该峰具有明显的吸附性;吸附粒子为LF中性分子,测得LF在汞电极上的饱和吸附量Гs=4.31×10-11mol·cm-2,每个LF分子所占电极面积为2.12nm2,LF在汞电极上的吸附符合Langmuir吸附等温式;测得吸附系数β=1.11×106,25℃时的吸附自由能ΔGθ=-35.24kJ·mol-1,电极反应电子数n=2,不可逆体系动力学参量αna=1.21,表面电极反应速率常量ks=0.31s-1;建立了吸附溶出伏安法测定LF的最佳条件,方法的检出限为2.0×10-8mol·L-1.
In a supporting electrolyte of 0.25mol·L-1KH2PO4-NaH2PO4 （pH6.38）, a reduction peac of Lomenfloxacin （LF） with a potential of -1.24V （vs Ag/AgCL） and adsorptive characteristics at the electrode is observed by linear sweep voltammetry at Hg electrode. The adsorbed species are most probably the neutral molecules of LF. The saturated adsorption amount of 4.31×10-11mol·cm-2 and an area occupied by each molecule of 2.12nm2 at Hg electrode for LF are obtained. On the surface of the hanging mercury drop electrode, the adsorption obeys langmuir adsorptiom isotherm. The adsorption coefficient β, the Gibbs energy of adsorption Gθ at 25 ℃, the number of electrons transferred n , the kinetic parameter an of the irrevpersible system αnα and the rate constant ks of surface electrode reaction ks are 1.11×106,-35.24KJ·mol-1,2,1.21 and 0.31s-1, respectively. A method for the assay of LF is proposed by adsorptive stripping voltammetry. The detection limit of the method is 2.0 ×10-8 mol·L-1 under the optimized conditions.
出处
《渭南师范学院学报》
2009年第2期40-44,共5页
Journal of Weinan Normal University
基金
陕西省教育厅专项科研计划项目(06JK303)
关键词
盐酸洛美沙星
吸附溶出伏安法
电化学行为
药物分析
Lomenfloxacin
adsorptive stripping voltammetry
electrochemical behavior
pharmaceutical analysis
