Temerk Y M, Kamal M M, Ahmed G A W, Ibrahim H S M
Chemistry Department, Assiut University, Assiut, Egypt.
Anal Sci. 2003 Aug;19(8):1115-9. doi: 10.2116/analsci.19.1115.
The surface activity of xanthine (Xan) and xanthosine (Xano) at a hanging mercury drop electrode (HMDE) was studied using out-of-phase ac and cyclic dc voltammetry. The results show that Xan and Xano were strongly adsorbed and chemically interacted with the charged mercury surface, which is the prerequisite step for applying the cathodic adsorptive stripping voltammetric determination of such biologically important compounds. Differential pulse cathodic adsorptive stripping voltammetry (DPCASV) and square-wave cathodic adsorptive stripping voltammetry (SWCASV) were applied for the ultratrace determination of Xan and Xano compounds. Moreover, a rapid and sensitive controlled adsorptive accumulation of Cu(II) complexes of both compounds provided the basis of a direct stripping voltammetric determination of such compounds to submicromolar and nanomolar levels. Operational and solution conditions for the quantitative ultratrace determination of Xan and Xano were optimized in absence and presence of Cu(II). The calibration curve data were subjected to least-squares refinements. The effects of several types of inorganic and organic interfering species on the determination of Xan or Xano were considered.
使用异相交流和循环直流伏安法研究了黄嘌呤（Xan）和黄苷（Xano）在悬汞滴电极（HMDE）上的表面活性。结果表明，Xan和Xano被强烈吸附并与带电汞表面发生化学相互作用，这是应用阴极吸附溶出伏安法测定此类具有重要生物学意义的化合物的前提步骤。采用差分脉冲阴极吸附溶出伏安法（DPCASV）和方波阴极吸附溶出伏安法（SWCASV）对Xan和Xano化合物进行超痕量测定。此外，两种化合物的铜（II）配合物的快速灵敏的可控吸附积累为直接溶出伏安法测定此类化合物至亚微摩尔和纳摩尔水平提供了基础。在不存在和存在铜（II）的情况下，优化了Xan和Xano定量超痕量测定的操作和溶液条件。对校准曲线数据进行了最小二乘法优化。考虑了几种无机和有机干扰物质对Xan或Xano测定的影响。
