Department of Chemistry, Memorial University of Newfoundland, 45 Arctic Avenue, St. John's, Newfoundland, Canada, A1C 5S7.
Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States.
Anal Chem. 2022 Aug 16;94(32):11113-11117. doi: 10.1021/acs.analchem.2c02351. Epub 2022 Aug 1.
Gas chromatography multiplexed with cyclic ion mobility mass spectrometry is a comprehensive two-dimensional separation technique that can resolve compounds that would otherwise coelute in a single-dimension separation. The cyclic geometry of the ion mobility cell enables ions to travel multiple passes, increasing their drift times to the detector and relative separation. However, the quality of the separation may be obfuscated when "wrap-around" occurs, during which speedier ions catch up with slower ion populations when allowed to travel through more than one pass. Consequently, cyclic ion mobility is incorrectly perceived as a targeted approach that requires preselection of ions prior to separation. The present study demonstrates that "wrap-around" can be mitigated by comparing drift times measured during single- and multipass experiments and extrapolating the number of passes experienced by each ion. This straightforward calculation results in the "unwrapping" of cyclic ion mobility data so that the experiments can be interpreted in a nontargeted way while reaping the benefit of peak capacities that rival those achieved using other comprehensive two-dimensional separations.
气相色谱-循环离子淌度质谱联用是一种综合二维分离技术，可分离在单维分离中会共流出的化合物。离子淌度池的循环几何形状使离子能够多次通过，增加它们到达检测器的漂移时间和相对分离度。然而，当发生“环绕”现象时，分离的质量可能会变得模糊，在这种现象中，当允许离子通过多个通道时，速度较快的离子会追上速度较慢的离子群体。因此，循环离子淌度被错误地认为是一种需要在分离前预先选择离子的靶向方法。本研究表明，通过比较单通道和多通道实验中测量的漂移时间，并推断每个离子经历的通道数量，可以减轻“环绕”现象。这种简单的计算方法可以“解缠”循环离子淌度数据，以便以非靶向的方式解释实验结果，同时获得与使用其他综合二维分离技术相当的峰容量。
