Lawal Remilekun O, Donnarumma Fabrizio, Murray Kermit K
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana, USA.
J Mass Spectrom. 2019 Mar;54(3):281-287. doi: 10.1002/jms.4338.
A 193-nm wavelength deep ultraviolet laser was used for ambient laser ablation electrospray ionization mass spectrometry of biological samples. A pulsed ArF excimer laser was used to ablate solid samples, and the resulting plume of the desorbed material merged with charged electrospray droplets to form ions that were detected with a quadrupole time-of-flight mass spectrometer. Solutions containing peptide and protein standards up to 66-kDa molecular weight were deposited on a metal target, dried, and analyzed. No fragmentation was observed from peptides and proteins as well as from the more easily fragmented vitamin B molecule. The mass spectra contained peaks from multiply charged ions that were identical to conventional electrospray. Deep UV laser ablation of tissue allowed detection of lipids from untreated tissue. The mechanism of ionization is postulated to involve absorption of laser energy by a fraction of the analyte molecules that act as a sacrificial matrix or by residual water in the sample.
一台波长为193纳米的深紫外激光用于生物样品的常压激光烧蚀电喷雾电离质谱分析。使用脉冲ArF准分子激光烧蚀固体样品，解吸物质产生的羽流与带电的电喷雾液滴合并形成离子，这些离子用四极杆飞行时间质谱仪进行检测。将含有分子量高达66 kDa的肽和蛋白质标准品的溶液沉积在金属靶上，干燥后进行分析。未观察到肽、蛋白质以及更易裂解的维生素B分子发生裂解。质谱图中包含来自多电荷离子的峰，这些峰与传统电喷雾产生的峰相同。对组织进行深紫外激光烧蚀可检测未处理组织中的脂质。推测电离机制涉及一部分充当牺牲基质的分析物分子或样品中的残留水吸收激光能量。
