Surface acoustic wave nebulization (SAWN) is a novel method to transfer non-volatile analytes directly from the aqueous-phase to the gas-phase for mass spectrometric analysis. The lower ion energetics of SAWN and its planar nature make it appealing for analytically challenging lipid samples. This challenge is a result of their amphipathic nature, labile nature, and tendency to form aggregates, which readily precipitate clogging capillaries used for electrospray ionization (ESI). Here we report the use of SAWN to characterize the complex glycolipid, lipid A, which serves as the membrane anchor component of lipopolysaccharide (LPS) and has a pronounced tendency to clog nano-ESI capillaries. We also show that unlike ESI SAWN is capable of ionizing labile phospholipids without fragmentation. Lastly, we compare the ease of use of SAWN to the more conventional infusion-based ESI methods and demonstrate the ability to generate higher order tandem mass spectral data of lipid A for automated structure assignment using our previously reported hierarchical tandem mass spectrometry (HiTMS) algorithm. The ease of generating SAWN-MSn data combined with HiTMS interpretation offers the potential for high throughput lipid A structure analysis.
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机译:声表面波雾化(SAWN)是一种将非挥发性分析物直接从水相转移到气相以进行质谱分析的新颖方法。 SAWN的较低离子能级及其平面性质使其对分析具有挑战性的脂质样品具有吸引力。该挑战是其两亲性质,不稳定性质以及形成聚集体的趋势的结果,这些聚集体容易沉淀出用于电喷雾电离(ESI)的堵塞毛细管。在这里,我们报告使用SAWN来表征复杂的糖脂,脂质A,它作为脂多糖(LPS)的膜锚定成分,并具有明显堵塞纳米ESI毛细管的趋势。我们还表明,与ESI不同,SAWN能够电离不稳定的磷脂而不会断裂。最后,我们将SAWN的易用性与更传统的基于输液的ESI方法进行了比较,并证明了使用我们以前报道的分层串联质谱(HiTMS)算法生成脂质A的高阶串联质谱数据以进行自动结构分配的能力。易于生成SAWN-MS n sup>数据与HiTMS解释相结合,为高通量脂质A结构分析提供了潜力。
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