Evaporation and Discharge Dynamics of Highly Charged Multicomponent Droplets Generated by Electrospray Ionization
Evaporation and Discharge Dynamics of Highly Charged Multicomponent Droplets Generated by Electrospray Ionization
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DOI：
10.1021/jp907162w
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发表时间：
2010-01-28
影响因子：
2.9
通讯作者：
Beauchamp, J. L.
中科院分区：
文献类型：
--
作者：
Grimm, Ronald L.;Beauchamp, J. L.
我们调查的瑞利放电和蒸发动力学的高度带电的两种成分的液滴主要由甲醇与2-甲氧基乙醇，叔丁醇，或间硝基苯甲醇。相位多普勒风速仪（PDA）在离子迁移谱仪（IMS）中根据电喷雾电离（ESI）产生的液滴在均匀电场中运动时的大小、速度、电荷种类来表征液滴。重复的场反转导致液滴“乒乓”通过PDA。这产生了溶剂蒸发行为的单个液滴历史和在瑞利放电事件期间电荷损失到后代液滴的动态。平均而言，甲醇液滴以其电荷的瑞利极限q（R）的127%放电，释放净电荷的25%。电荷损失前甲醇/2-甲氧基乙醇液滴的行为类似于纯的2-甲氧基乙醇液滴，其释放类似于其净电荷的28%。含有Lip至50%叔丁醇的二元甲醇液滴以比纯甲醇更低的百分比q（R）放电，并释放更大部分的净电荷。99%甲醇/1%间硝基苯甲醇混合液滴具有与甲醇相似的放电特性。然而，含有2%间硝基苄基的甲醇液滴蒸发到固定的尺寸和电荷，保持恒定，没有可观察到的放电。准稳态蒸发模型准确地描述了所观察到的蒸发现象，其中甲醇/叔丁醇液滴以与纯甲醇相似的速率蒸发，甲醇/2-甲氧基乙醇液滴以与2-甲氧基乙醇相似的速率蒸发。我们将这些结果与以前的瑞利放电实验进行比较，并讨论了电喷雾质谱（ESI-MS）和场诱导液滴电离质谱（FIDI-MS）中二元溶剂的影响。
We investigate the Rayleigh discharge and evaporation dynamics of highly charged two-component droplets consisting principally of methanol with 2-methoxyethanol, tert-butanol, or m-nitrobenzyl alcohol. A phase Doppler anemometer (PDA) characterizes droplets generated by electrospray ionization (ESI) according to size, velocity, kind charge as they move through it uniform electric field within an ion mobility spectrometer (IMS). Repeated field reversals result in droplet "ping-pong" through the PDA. This generates individual droplet histories Of Solvent evaporation behavior and the dynamics Of charge loss to progeny droplets during Rayleigh discharge events. On average, methanol droplets discharge at 127% their Rayleigh limit of charge, q(R), kind release 25% of the net charge. Charge loss front methanol/2-methoxyethanol droplets behaves similarly to pure, 2-methoxyethanol droplets which release similar to 28% of their net charge. Binary methanol droplets containing Lip to 50% terr-butanol discharge at a lower percent q(R) than pure methanol and release a greater fraction of their net charge. Mixed 99% methanol/1% m-nitrobenzyl alcohol droplets possess discharge characteristics similar to those of methanol. However, droplet's of methanol containing 2% m-nitrobenzyl evaporate down to a fixed size and charge that remains constant with no observable discharges. Quasi-steady-state evaporation models accurately describe observed evaporation phenomena in which methanol/tert-butanol droplets evaporate at a rate similar to that of pure methanol and methanol/2-methoxyethanol droplets evaporate at a rate similar to that of 2-methoxyethanol. We compare these results to previous Rayleigh discharge experiments and discuss the implications for binary solvents in electrospray mass spectrometry (ESI-MS) and field-induced droplet ionization mass spectrometry (FIDI-MS).