Imaging of triglycerides in tissues using nanospray desorption electrospray ionization (Nano-DESI) mass spectrometry,International Journal of Mass Spectrometry

当前位置： X-MOL 学术 › Int. J. Mass Spectrom. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Imaging of triglycerides in tissues using nanospray desorption electrospray ionization (Nano-DESI) mass spectrometry
International Journal of Mass Spectrometry ( IF 1.6 ) Pub Date : 2020-02-01 , DOI: 10.1016/j.ijms.2019.116269
Daisy Unsihuay ₁ , Jiamin Qiu ₂ , Sneha Swaroop ₁ , Konstantin O Nagornov ₃ , Anton N Kozhinov ₃ , Yury O Tsybin ₃ , Shihuan Kuang ₂ , Julia Laskin ₁

Affiliation

Nonpolar triglycerides (TGs) are rarely detected in mass spectrometry imaging (MSI) experiments unless they are abundant in the sample. Herein, we use nanospray desorption electrospray ionization (nano-DESI) to explore the role of the solvent composition and ionic dopants on the detection of TGs in a murine gastrocnemius muscle tissue used as a model system. We evaluated three solvent mixtures for their ability to extract nonpolar TG species: MeOH:H2O 9:1 (v/v), MeOH:DCM 6:4 (v/v) and MeOH:AcN:tol 5:3.5:1.5 (v/v/v). We observe that TGs are mainly detected as [M+K]+ adducts and their extraction efficiency is improved using less polar solvents: MeOH:DCM and MeOH:AcN:tol. We also explore whether the ionization efficiency of TGs may be improved by doping the MeOH:AcN:tol solvent with ammonium formate (AF) and other ionic additives. However, the formation of [M+NH4]+ adducts of TGs is less efficient than the formation of [M+K]+ adducts in the range of AF concentrations from 0.1 to 10 mM. Chemical derivatization using 100 μM of Girard T reagent predominately generates reaction products of phosphatidylcholine rather than TG species. Moreover, the presence of the Girard T reagent suppresses ion signals of all the species in the spectrum including TGs. Nano-DESI MSI experiments performed using MeOH:AcN:tol solvent enable imaging of TGs without any detectable adverse effect on signals of other lipids and metabolites. Specifically, 10 out of 14 TG species were detected exclusively using MeOH:AcN:tol and the sensitivity towards other TGs was improved by at least an order of magnitude. Although polyunsaturated TGs may be detected using both solvents, saturated and monounsaturated TGs are only detected using MeOH:AcN:tol. Our results provide a direct path for the improved detection of TGs in tissue imaging experiments using liquid-based ambient ionization techniques.

中文翻译：

使用纳喷雾解吸电喷雾电离 (Nano-DESI) 质谱法对组织中的甘油三酯进行成像

非极性甘油三酯 (TG) 在质谱成像 (MSI) 实验中很少检测到，除非它们在样品中含量丰富。在此，我们使用纳喷雾解吸电喷雾电离 (nano-DESI) 来探索溶剂成分和离子掺杂剂对用作模型系统的小鼠腓肠肌组织中 TG 检测的作用。我们评估了三种溶剂混合物提取非极性 TG 物质的能力：MeOH:H2O 9:1 (v/v)、MeOH:DCM 6:4 (v/v) 和 MeOH:AcN:tol 5:3.5:1.5 (v /v/v）。我们观察到，TG 主要以 [M+K]+ 加合物的形式被检测到，并且使用极性较小的溶剂：MeOH:DCM 和 MeOH:AcN:tol 可以提高其提取效率。我们还探讨了是否可以通过在 MeOH:AcN:tol 溶剂中掺杂甲酸铵 (AF) 和其他离子添加剂来提高 TG 的电离效率。然而，在 0.1 至 10 mM AF 浓度范围内，TG 的 [M+NH4]+ 加合物的形成效率低于 [M+K]+ 加合物的形成效率。使用 100 μM Girard T 试剂进行的化学衍生化主要生成磷脂酰胆碱而不是 TG 物质的反应产物。此外，Girard T 试剂的存在会抑制光谱中包括 TG 在内的所有物种的离子信号。使用 MeOH:AcN:tol 溶剂进行的 Nano-DESI MSI 实验能够对 TG 进行成像，而不会对其他脂质和代谢物的信号产生任何可检测到的不利影响。具体而言，仅使用 MeOH:AcN:tol 检测了 14 种 TG 中的 10 种，并且对其他 TG 的敏感性至少提高了一个数量级。虽然多不饱和 TG 可以使用两种溶剂检测，但饱和和单不饱和 TG 只能使用 MeOH:AcN:tol 检测。我们的结果为使用基于液体的环境电离技术在组织成像实验中改进 TG 检测提供了直接途径。

更新日期：2020-02-01

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11