Li Hai-Fang, Zhao Jing, Cao Wenbo, Zhang Wenpeng, Xia Yu, Ouyang Zheng
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.
MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
Research (Wash D C). 2022 Feb 12;2022:9783602. doi: 10.34133/2022/9783602. eCollection 2022.
Unraveling the complexity of the lipidome requires the development of novel approaches to facilitate structural identification and characterization of lipid species with isomer-level discrimination. Ultraviolet photodissociation tandem mass spectrometry (UVPD MS/MS) is a promising tool for structure determination of lipids. The sensitivity of UVPD for lipid analysis however is limited mainly due to weak absorption of UV photons by a C=C. Herein, a C=C site-specific derivatization, the Paternò-Büchi (PB) reaction, was used to incorporate a chromophore to the C=C moiety in fatty acyls, leading to significantly improved UVPD efficiency and sensitivity for pinpointing C=C locations. The wavelength-dependent photodissociation of the PB products demonstrated 4-CF-benzophenone as the best reagent for UVPD in terms of the efficiency of generating C=C diagnostic fragments and simplicity for C=C location assignments. We demonstrated the effectiveness of this approach for the shotgun profiling of C=C location isomers in different lipid classes from complex lipid extracts, highlighting its potential to advancing the identification of the C=C bond locations in unsaturated lipids.
揭示脂质组的复杂性需要开发新方法，以促进脂质种类的结构鉴定和表征，并实现异构体水平的区分。紫外光解离串联质谱（UVPD MS/MS）是一种很有前景的脂质结构测定工具。然而，UVPD用于脂质分析的灵敏度有限，主要原因是碳碳双键（C=C）对紫外光子的吸收较弱。在此，我们利用一种碳碳双键位点特异性衍生化反应——帕特诺-比希（PB）反应，将一个发色团引入脂肪酰基中的碳碳双键部分，从而显著提高了UVPD效率以及确定碳碳双键位置的灵敏度。PB产物的波长依赖性光解离表明，就生成碳碳双键诊断性碎片的效率和碳碳双键位置分配的简便性而言，4-三氟甲基二苯甲酮是UVPD的最佳试剂。我们证明了该方法在对复杂脂质提取物中不同脂质类别进行碳碳双键位置异构体鸟枪法分析方面的有效性，突出了其在推进不饱和脂质中碳碳双键位置鉴定方面的潜力。
