本文第一部分，采用毛细管电泳-电容耦合非接触电导法（CE-C4D）检测牛奶中金属离子和三聚氰胺的含量。以20 mM乳酸溶液为背景电解质，采用50 μm × 50 cm 毛细管（有效长度40 cm），电导检测器的操作参数设置为180 kHz × 8 V，对标准品和牛奶中K+、Ca2+、Na+以及三聚氰胺的检出限分别为0.009~0.040 mg/kg和0.10~0.20 mg/kg。本方法仪器简单、操作费用低，可以对牛奶中三聚氰胺以及没有光学活性的无机离子进行快速准确检测。本文第二部分，对树枝状大分子（PAMAM G 0.5）作为缓冲溶液的添加剂改善毛细管电泳分离分析金属离子进行了研究。将4-(2-吡啶偶氮)-间苯二酚（PAR）加入硼酸盐缓冲中，用紫外-可见法对五种金属离子，即Pb2+，Co2+，Cu2+，Fe3+，Zn2+ 进行检测。树枝状大分子与金属离子之间存在供体-受体相互作用和包合作用，与各金属络合物存在静电作用，这就增大了各金属离子间的淌度差异，可改善分离效果。在硼酸盐缓冲中加入2 mM PAMAM G 0.5后，五种金属离子得到快速高效的分离，Pb2+的检测灵敏度提高了5.5倍。将该方法用于黄酒中金属离子的检测，其结果与电感耦合等离子体原子发射光谱法相符合。这说明，树枝状大分子可作为有效的添加剂用于复杂基质中金属离子的分离分析。

In the first part, a method combining capillary electrophoresis (CE) and capacitively coupled contactless conductivity detection (C4D) was developed for determination of melamine and metal ions, namely, potassium, calcium and sodium, in milk. The original or fortified milk sample was first added with trichloroacetic acid to remove proteins, followed by dilution and filtration for metal ion detection or by solid-phase extraction for CE assaying the melamine. CE separation was carried out in a 50 μm × 50 cm capillary; and the detection parameters of C4D were set to 180 kHz × 8 V. With 20 mM lactic acid as background electrolyte, the detection limits of K+、Ca2+、Na+ and melamine were in the range of 0.009~0.040 mg/kg and 0.10~0.20 mg/kg for the standard solution and milk sample, respectively. Our experiments suggest that the method is cost-effective and easy to follow; it is suitable for real sample analysis.In the second part, we reported an enhanced performance for capillary electrophoretic separation of five metal ions, viz, Pb2+, Co2+, Cu2+, Fe3+ and Zn2+, by adding poly(amidoamine) dendrimer generation 0.5 (PAMAM G 0.5) to a borate buffer containing 4-(2-pyridylazo) resorcinol (PAR) as a chromogenic reagent. PAMAMs influenced mobilities of the metal ions via the donor-acceptor interaction and encapsulation between metal ions and PAMAMs, and via the electrostatic interaction between the dendrimer and the metal ion-PAR complexes. Presence of 2 mM PAMAM G 0.5 in the buffer of 12 mM H3BO3, 7 mM Na2B4O7, 0.1 mM PAR at pH 8.8 improved the separation efficiency of all the ions, enabled baseline resolution of the initially overlapped Cu2+ and Fe3+, and amplified the detection sensitivity of Pb2+ by 5.5 folds. The method was successfully applied in determination of metal ions in a rice wine sample, and the results agreed well with that obtained by inductively coupled plasma atomic emission spectrometry. Our experiments suggested that the PAMAM-assisted capillary electroseparation could be used for the selective and sensitive detection of metal ions in complex matrices.