Insights into the cITP process using on-line NMR spectroscopy.
Insights into the cITP process using on-line NMR spectroscopy.
复制标题
使用在线 NMR 光谱深入了解 cITP 过程。
DOI：
10.1021/ac025585p
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发表时间：
2002
影响因子：
7.4
通讯作者：
Sweedler,JonathanV
中科院分区：
文献类型：
--
作者：
Wolters,AndrewM;Jayawickrama,DimuthuA;Larive,CynthiaK;Sweedler,JonathanV
近年来，毛细管等速电泳法(CITP)已与核磁共振(NMR)联用，通过样品浓缩和分离来加强稀荷分析物的分析。本研究的重点是核磁共振独特的检测能力，以非侵入性地检查CITP过程并获得诊断信息。凭借其增强的质量灵敏度，微线圈核磁共振探针为CITP/核磁共振提供了最佳检测。以前的研究使用的是氢化缓冲液，而1H核磁共振可观察到的领先电解液四甲基醋酸铵在这里被用来更好地跟踪CITP的进展。幸运的是，乙酸甲酯共振的1H化学位移依赖于Pd。因此，在CITP过程中，通过使用校准曲线，可以在线测定溶液Pd。同样，在CITP/核磁共振中，可以通过观察HOD化学位移来测量毛细血管内温度。为了获得准确的化学位移测量，在所有CITP电解液中加入电荷中性叔丁醇作为内部参照物。作为一个辅助的好处，泛素丁醇的线宽测量使核磁共振光谱分辨率能够在整个实验过程中得到检查。核磁共振能够提供定量结果，在CITP实验过程中同时测定前导离子、样品和反离子的浓度。
Recently, capillary isotachophoresis (cITP) has been coupled on-line with nuclear magnetic resonance (NMR) to enhance analysis of dilute charged analytes through sample concentration and separation. This study focuses on the unique detection capabilities of NMR to noninvasively examine the cITP process and obtain diagnostic information. With their enhanced mass sensitivity, microcoil NMR probes provide optimal detection for cITP/NMR. Whereas previous studies used deuterated buffers, a1H NMR observable leading electrolyte, tetramethylammonium acetate, is employed here to better track cITP progression. Fortuitously, the1H chemical shift of the acetate methyl resonance depends on pD. Hence, by using a calibration curve, the solution pD can be determined on-line during cITP. Similarly, intracapillary temperature can be measured in cITP/NMR by observing the HOD chemical shift. To obtain accurate chemical shift measurements, charge-neutraltert-butyl alcohol is added to all cITP electrolyte solutions as an internal reference. As an ancillary benefit, line width measurements of the ubiquitoustert-butyl alcohol enable NMR spectral resolution to be examined throughout the experiment. Capable of providing quantitative results, NMR simultaneously determines the concentrations of the leading ion, sample, and counterion over the course of the cITP experiment.