Understanding and elucidating the diverse structures and functions of lipids has motivated the development of many innovative tandem mass spectrometry (MS/MS) strategies. Higher-energy activation methods, such as ultraviolet photodissociation (UVPD), generate unique fragment ions from glycerophospholipids that can be used to perform in-depth structural analysis and facilitate the deconvolution of isomeric lipid structures in complex samples. Although detailed characterization is central to the correlation of lipid structure to biological function, it is often impeded by the lack of sufficient instrument sensitivity for highly bioactive but low-abundance phospholipids. Here, we present precursor exclusion (PEx) UVPD, a simple yet powerful technique to enhance the signal-to-noise (S/N) of informative low-abundance fragment ions produced from UVPD of glycerophospholipids. Through the exclusion of the large population of undissociated precursor ions with an MS³ strategy, the S/N of diagnostic fragment ions from PC 18:0/18:2(9Z, 12Z) increased up to an average of 13x for PEx-UVPD compared to UVPD alone. These enhancements were extended to complex mixtures of lipids from bovine liver extract to confidently identify 35 unique structures using liquid chromatography PEx-UVPD. This methodology has the potential to advance lipidomics research by offering deeper structure elucidation and confident identification of biologically active lipids.

中文翻译：

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通过前体排斥紫外光解离质谱 (PEx-UVPD-MS) 增强不饱和甘油磷脂诊断片段离子的信噪比

了解和阐明脂质的不同结构和功能推动了许多创新串联质谱 (MS/MS) 策略的开发。更高能量的激活方法，例如紫外线光解 (UVPD)，可以从甘油磷脂中产生独特的碎片离子，可用于进行深入的结构分析并促进复杂样品中异构脂质结构的解卷积。尽管详细表征对于脂质结构与生物功能的相关性至关重要，但对于高生物活性但低丰度的磷脂缺乏足够的仪器灵敏度，这往往会阻碍其进行。在这里，我们提出了前体排除 (PEx) UVPD，这是一种简单而强大的技术，可增强甘油磷脂 UVPD 产生的信息性低丰度碎片离子的信噪比 (S/N)。^{通过使用 MS 3}策略排除大量未解离的前体离子，PC 18:0/18:2(9 Z , 12 Z )中诊断碎片离子的信噪比平均增加至 PEx 的 13 倍-UVPD 与单独 UVPD 相比。这些增强功能已扩展到牛肝提取物中的复杂脂质混合物，可以使用液相色谱 PEx-UVPD 自信地识别 35 种独特的结构。该方法有可能通过提供更深入的结构阐明和生物活性脂质的可靠鉴定来推进脂质组学研究。