Choy Tom M H, Huie Carmen W
Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
Electrophoresis. 2003 Sep;24(17):3040-8. doi: 10.1002/elps.200305517.
New insights into the effects of the wall adsorption of the visualization agent on baseline noise characteristics in indirect UV detection in capillary electrophoresis were provided. When compared to relatively small, hydrophilic cationic (1-(4-pyridyl)pyridinium chloride hydrochloride) or anionic chromophores (bromide and benzoate), the use of a UV-absorbing long-chain cationic surfactant (benzyldimethylhexadecylammonium chloride) as a probe (visualization agent) for studying baseline noise characteristics as a function of various experimental conditions, such as applied voltage, pH or buffer composition, was found to provide noise data that were very different under certain conditions. For cationic visualization agents that have a strong tendency of adsorbing onto the capillary surfaces due to electrostatic and/or hydrophobic interactions, it appeared that the interplay of both thermal as well as adsorption/desorption events occurring within the capillary is likely responsible for a fluctuation of the visualization agent concentration at the detector.
本文提供了关于可视化试剂在毛细管电泳间接紫外检测中壁吸附对基线噪声特性影响的新见解。与相对较小的亲水性阳离子（盐酸1-(4-吡啶基)吡啶鎓）或阴离子发色团（溴化物和苯甲酸盐）相比，使用一种紫外吸收长链阳离子表面活性剂（苄基二甲基十六烷基氯化铵）作为探针（可视化试剂）来研究基线噪声特性与各种实验条件（如施加电压、pH值或缓冲液组成）的函数关系，发现在某些条件下能提供非常不同的噪声数据。对于由于静电和/或疏水相互作用而强烈倾向于吸附在毛细管表面的阳离子可视化试剂，似乎毛细管内发生的热事件以及吸附/解吸事件的相互作用可能是导致检测器处可视化试剂浓度波动的原因。
