Campus de San Pablo, Programa de Química, Universidad de Cartagena, Cartagena, Colombia.
National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia.
Rapid Commun Mass Spectrom. 2022 Oct 30;36(20):e9360. doi: 10.1002/rcm.9360.
Ion mobility spectrometry (IMS) detects illegal substances and explosives in airports, ports, and customs. This is complicated by false positives caused by overlapping peaks. Shift reagents selectively change ion mobilities through adduction with analyte ions. This discriminates false positives because interferents and illegal substances respond differently to shift reagents.
We introduced five different shift reagents using electrospray ionization-IMS-mass spectrometry to study the effect of interaction energy, intermolecular bonds, and analyte size on ion mobility shifts. Analyte ion-shift reagent interactions were calculated using Gaussian.
The mobility shifts showed a decreasing trend as the molecular weight increased for a series of ten compounds. The shift in drift time better reflected the pure effect of shift reagents. Valinol was an exception to this trend because it had a low binding energy interaction with all shift reagents and, consequently, its clusters were short-lived. This produced fewer collisions against the buffer gas and a shorter drift time, compared to ions of similar molecular weight.
The results of this investigation are important for understanding the behavior of shift reagents in resolving overlapping peaks that cause interferences. The suppression of false positives eases the transit of passengers and cargos, increases the confiscation of illicit substances, and saves money and distress due to needless delays in customs and airports.
离子迁移谱（IMS）可用于在机场、港口和海关检测非法物质和爆炸物。但由于重叠峰会导致假阳性，这一过程变得复杂。移位试剂通过与分析物离子加成选择性地改变离子迁移率。这可以区分假阳性，因为干扰物和非法物质对移位试剂的反应不同。
我们使用电喷雾电离-IMS-质谱法引入了五种不同的移位试剂，以研究相互作用能、分子间键和分析物大小对离子迁移率位移的影响。使用 Gaussian 计算分析物离子-移位试剂相互作用。
对于一系列十种化合物，随着分子量的增加，迁移率的位移呈下降趋势。漂移时间的位移更好地反映了移位试剂的纯效应。缬氨醇是这种趋势的例外，因为它与所有移位试剂都具有低结合能相互作用，因此其团簇的寿命短。与分子量相似的离子相比，这会导致与缓冲气体的碰撞减少，漂移时间缩短。
这项研究的结果对于理解移位试剂在解决导致干扰的重叠峰方面的行为非常重要。抑制假阳性可以减轻乘客和货物的过境负担，增加非法物质的没收量，并节省因海关和机场不必要的延误而造成的金钱和困扰。
