Max Planck Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149 , Hamburg 22761 , Germany.
Anal Chem. 2018 Apr 3;90(7):4422-4428. doi: 10.1021/acs.analchem.7b04306. Epub 2018 Mar 21.
We report the soft laser extraction and production of highly charged peptide and protein ions for mass spectrometry directly from bulk liquid water at atmospheric pressure and room temperature, using picosecond infrared laser ablation. Stable ion signal from singly charged small molecules, as well as highly charged biomolecular ions, from aqueous solutions at low laser pulse fluence (∼0.3 J cm) is demonstrated. Sampling via single picosecond laser pulses is shown to extract less than 27 pL of volume from the sample, producing highly charged peptide and protein ions for mass spectrometry detection. The ablation and ion generation is demonstrated to be soft in nature, producing natively folded proteins ions under sample conditions described for native mass spectrometry. The method provides laser-based sampling flexibility, precision and control with highly charged ion production directly from water at low and near neutral pH. This approach does not require an additional ionization device or high voltage applied directly to the sample.
我们报告了在大气压和室温下，使用皮秒红外激光烧蚀，直接从液体水中软激光提取和产生高电荷肽和蛋白质离子，用于质谱分析。在低激光脉冲能量（约 0.3 J cm）下，从小分子单电荷到生物分子多电荷离子，均能从水溶液中得到稳定的离子信号。单皮秒激光脉冲采样可从样品中提取小于 27 pL 的体积，产生可用于质谱检测的高电荷肽和蛋白质离子。证明了烧蚀和离子产生具有软性质，在描述的天然质谱条件下产生天然折叠的蛋白质离子。该方法提供了基于激光的采样灵活性、精度和控制，可直接从低 pH 值和近中性 pH 值的水中产生高电荷离子。该方法不需要额外的离子化装置或直接施加到样品上的高压。
