An on-column contact conductivity detector was developed for the analysis of various mono- and polyanionic compounds separated by electrophoresis chips fabricated in poly(methyl methacrylate) (PMMA) using hot embossing techniques from Ni electroforms. The detector consisted of a pair of Pt wires (127 microm diameter) with an end-to-end spacing of approximately 20 microm and situated within the fluidic channel. The waveform applied to the electrode pair was a bipolar pulse with a frequency of 5.0 kHz and was used to reduce the charging current from measurement so that the current recorded at the end of one pulse is more representative of the solution conductivity. Using the detector, separations of amino acids, peptides, proteins, and oligonucleotides were demonstrated. For the amino acids and peptides, free-solution zone electrophoresis was performed. A calibration plot for the amino acid alanine was found to be linear from approximately 10 to 100 nM in a carrier electrolyte consisting of 10 mM triethylamonium acetate. The concentration detection limit was found to be 8.0 nM, with the corresponding mass detection limit equal to 3.4 amol (injection volume = 425 pL). The protein separations with conductivity detection were performed using MEKC, in which the carrier electrolyte contained the anionic surfactant sodium dodecyl sulfate (SDS) above its cmc. Near baseline resolution was achieved in the PMMA microchip for a solution containing 8 different proteins. In the case of the DNA fragments, capillary electrochromatography was used with a C18-modified PMMA chip and a carrier electrolyte containing an ion-pairing agent.

中文翻译：

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基于聚（甲基丙烯酸甲酯）的微流控设备中的接触电导检测，用于分析单阴离子和聚阴离子分子。

研发了一种柱上接触电导检测器，用于分析通过使用Ni电铸的热压印技术，在聚甲基丙烯酸甲酯（PMMA）中制造的电泳芯片分离的各种单阴离子和聚阴离子化合物。该检测器由一对Pt线（直径127微米）组成，其端对端间距约为20微米，并位于流体通道内。施加到电极对的波形是频率为5.0 kHz的双极性脉冲，用于减少测量的充电电流，以使在一个脉冲结束时记录的电流更能代表溶液的电导率。使用检测器，证明了氨基酸，肽，蛋白质和寡核苷酸的分离。对于氨基酸和肽，进行自由溶液区电泳。发现在由10 mM乙酸三乙铵组成的载体电解质中，氨基酸丙氨酸的校准图从大约10到100 nM是线性的。发现浓度检测极限为8.0 nM，相应的质量检测极限等于3.4 amol（进样量= 425 pL）。使用MEKC进行具有电导检测的蛋白质分离，其中载体电解质在其cmc上方包含阴离子表面活性剂十二烷基硫酸钠（SDS）。对于包含8种不同蛋白质的溶液，在PMMA微芯片中获得了接近基线的分辨率。对于DNA片段，将毛细管电色谱与C18修饰的PMMA芯片和含有离子对剂的载体电解质一起使用。发现在由10 mM乙酸三乙铵组成的载体电解质中，氨基酸丙氨酸的校准图从大约10到100 nM是线性的。发现浓度检测极限为8.0 nM，相应的质量检测极限等于3.4 amol（进样量= 425 pL）。使用MEKC进行具有电导检测的蛋白质分离，其中载体电解质在其cmc上方包含阴离子表面活性剂十二烷基硫酸钠（SDS）。对于包含8种不同蛋白质的溶液，在PMMA微芯片中获得了接近基线的分辨率。对于DNA片段，将毛细管电色谱与C18修饰的PMMA芯片和含有离子对剂的载体电解质一起使用。发现在由10 mM乙酸三乙铵组成的载体电解质中，氨基酸丙氨酸的校准图在约10至100 nM之间呈线性关系。发现浓度检测极限为8.0 nM，相应的质量检测极限等于3.4 amol（进样量= 425 pL）。使用MEKC进行具有电导检测的蛋白质分离，其中载体电解质在其cmc上方包含阴离子表面活性剂十二烷基硫酸钠（SDS）。对于包含8种不同蛋白质的溶液，在PMMA微芯片中获得了接近基线的分辨率。对于DNA片段，将毛细管电色谱与C18修饰的PMMA芯片和含有离子对剂的载体电解质一起使用。