Cismesia Adam P, Tesler Larry F, Bell Matthew R, Bailey Laura S, Polfer Nicolas C
Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL, 32611-7200, USA.
J Mass Spectrom. 2017 Nov;52(11):720-727. doi: 10.1002/jms.3975.
We demonstrate operation of the first cryogenic 2D linear ion trap (LIT) with mass-selective capabilities. This trap presents a number of advantages for infrared ion "action" spectroscopy studies, particularly those employing the "tagging/messenger" spectroscopy approach. The high trapping efficiencies, trapping capacities, and low detection limits make 2D LITs a highly suitable choice for low-concentration analytes from scarce biological samples. In our trap, ions can be cooled down to cryogenic temperatures to achieve higher-resolution infrared spectra, and individual ions can be mass selected prior to irradiation for a background-free photodissociation scheme. Conveniently, multiple tagged analyte ions can be mass isolated and efficiently irradiated in the same experiment, allowing their infrared spectra to be recorded in parallel. This multiplexed approach is critical in terms of increasing the duty cycle of infrared ion spectroscopy, which is currently a key weakness of the technique. The compact design of this instrument, coupled with powerful mass selection capabilities, set the stage for making cryogenic infrared ion spectroscopy viable as a bioanalytical tool in small molecule identification.
我们展示了首个具有质量选择功能的低温二维线性离子阱（LIT）的运行情况。该离子阱对于红外离子“作用”光谱研究具有诸多优势，特别是对于那些采用“标记/信使”光谱方法的研究。高俘获效率、俘获容量以及低检测限使得二维线性离子阱成为从稀缺生物样品中分析低浓度分析物的非常合适的选择。在我们的离子阱中，离子可以被冷却至低温以获得更高分辨率的红外光谱，并且在照射之前可以对单个离子进行质量选择，以实现无背景光解离方案。方便的是，多个标记的分析物离子可以在同一实验中进行质量隔离并有效照射，从而能够并行记录它们的红外光谱。这种多路复用方法对于提高红外离子光谱的占空比至关重要，而占空比目前是该技术的一个关键弱点。该仪器的紧凑设计，再加上强大的质量选择能力，为使低温红外离子光谱作为一种用于小分子鉴定的生物分析工具成为可行奠定了基础。
