Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing, P. R. China.
Electrophoresis. 2010 Sep;31(17):2949-56. doi: 10.1002/elps.201000252.
A novel method was proposed for simultaneous measurement of diffusion coefficients, (D), from mixed samples by electrophoresis and termed electromigration-based diffusivity spectrometry. After theoretical treatment, D-equation for practical use has been deduced. With a modified CE system built in laboratory, electromigration-based diffusivity spectrometry has been realized and validated to suit for fast and accurate determination of diffusivities of mixed aromatic amino acids, phenols and aromatic organic acid, giving diffusivity spectra by peak area versus D, much similar to mass spectra. The precision of the measurement was found to critically depend on pH value of running buffer, which should be so selected that the analytes and internal standards could be charged at above 0.5e. The standards have to be selected at an electric flux far from each other and from analytes. In these cases, sample and running buffer concentrations, voltage and system temperature were found to have only negligible impact on the determination. In our test, the obtained measuring precision was generally kept within 1% for five runs, and the measured values of D agreed well with those from literature, with a deviation of less than 2.2% after the right use of calibration standards.
提出了一种新的方法，通过电泳同时测量混合样品中的扩散系数（D），并将其称为基于电泳的扩散光谱法。经过理论处理，推导出了适用于实际应用的 D 方程。通过在实验室中构建改进的 CE 系统，实现了基于电泳的扩散光谱法，并对其进行了验证，以适合快速准确地测定混合芳香族氨基酸、酚类和芳香族有机酸的扩散系数，通过峰面积与 D 的关系得到扩散光谱，与质谱非常相似。测量的精度被发现严重依赖于运行缓冲液的 pH 值，应选择使分析物和内标在 0.5e 以上带电。标准品必须在与分析物相距较远的电流量处选择。在这些情况下，样品和运行缓冲液浓度、电压和系统温度对测定的影响可以忽略不计。在我们的测试中，五个运行的测量精度通常保持在 1%以内，并且测量的 D 值与文献值吻合良好，在正确使用校准标准品后，偏差小于 2.2%。
