Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
Anal Chem. 2012 Feb 7;84(3):1725-31. doi: 10.1021/ac203013u. Epub 2012 Jan 17.
A simple space compression-dispersion model for ion transport at ambient pressure was mathematically established. On the basis of this model and aided by SIMION simulation, a three-zone theory was proposed to characterize the Bradbury-Nielsen gating electric field features as three zones: the depletion zone, the dispersion zone, and the compression zone. Then, the influences of gating voltage difference increases on the full width at half-maximum of the Cl(-) peak were investigated in detail to verify the theory. For example, at a gating voltage difference of 350 V and a gate pulse width of 0.34 ms, the ion packets injected were reduced to as low as 60% of their original widths, with the peak height increased from 756 to 808 pA and the resolution from 18 to 33, enhanced by 7% and ~80%, respectively. The ion mobility spectrometry (IMS) efficiency ratios, R(m)/R(c) and R(m)/R(p), were also raised above theoretical values and reached about 182% and 175%, respectively. The experimental results were explained using the proposed theory with good consistency. Finally, a compression coefficient was extracted by fitting the experimental data to the applied gate pulse width, presenting a good linearity. All this shows a potential application in improving the performances of ion mobility spectrometry.
建立了一种简单的常压离子输运压缩-弥散模型。基于该模型并借助 SIMION 模拟，提出了三区理论来描述 Bradbury-Nielsen 门控电场特征，分为耗尽区、弥散区和压缩区三个区域。然后，详细研究了门控电压差增加对 Cl(-)峰半峰宽的影响，以验证该理论。例如，在门控电压差为 350 V 和门控脉冲宽度为 0.34 ms 的条件下，注入的离子包被减小到原始宽度的 60%，峰高从 756 pA 增加到 808 pA，分辨率从 18 提高到 33，分别提高了 7%和 80%。离子迁移谱（IMS）效率比 R(m)/R(c) 和 R(m)/R(p) 也高于理论值，分别达到约 182%和 175%。实验结果与所提出的理论很好地吻合。最后，通过将门控脉冲宽度的实验数据拟合到压缩系数中，得到了很好的线性关系。所有这些都表明在提高离子迁移谱性能方面具有潜在的应用。
