A new atmospheric pressure (AP) infrared (IR) matrix-assisted laser desorption/ionization (MALDI) ion source was developed and interfaced with a Thermo Finnigan LCQ ion trap mass spectrometer. The source utilized a miniature all-solid-state optical parametric oscillator (OPO)-based IR laser system tunable in the lambda = 1.5-4 microm spectral range and a nitrogen ultraviolet (UV) laser (lambda = 337 nm) for use in comparative studies. The system demonstrated comparable performance at 3 microm and 337 nm wavelengths if UV matrices were used. However, AP IR-MALDI using a 3 microm wavelength showed good performance with a much broader choice of matrices including glycerol and liquid water. AP IR-MALDI mass spectra of peptides in the mass range up to 2000 Da were obtained directly from aqueous solutions at atmospheric conditions for the first time. A potential use of the new AP IR-MALDI ion source includes direct MS analysis of biological cells and tissues in a normal atmospheric environment as well as on-line coupling of mass spectrometers with liquid separation techniques.

中文翻译：

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使用3微米的红外激光在大气压力下从水溶液中解吸/离子化生物分子。

开发了一种新的常压（AP）红外（IR）基质辅助激光解吸/电离（MALDI）离子源，并将其与Thermo Finnigan LCQ离子阱质谱仪连接。该光源使用了可在λ= 1.5-4微米光谱范围内可调的基于微型全固态光学参量振荡器（OPO）的IR激光系统和用于比较的氮气（UV）激光（λ= 337 nm）学习。如果使用紫外线基质，该系统在3微米和337 nm波长处表现出可比的性能。但是，使用3微米波长的AP IR-MALDI在包括甘油和液态水在内的多种基质选择中均显示出良好的性能。首次直接从水溶液中在大气条件下获得质量范围高达2000 Da的肽的AP IR-MALDI质谱。