Wu Liutian, Qi Keke, Xu Minggao, Liu Chengyuan, Pan Yang
National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, China.
J Mass Spectrom. 2022 Mar;57(3):e4813. doi: 10.1002/jms.4813.
Desorption electrospray ionization/post-photoionization (DESI/PI) is a newly developed ionization method by the combination of DESI and post-photoionization for the simultaneous imaging of polar and nonpolar compounds in biological tissues. Dopants are of great importance in DESI/PI for the enhancement of signal intensities through ion-molecule reactions. In this work, to evaluate the performance of dopants in DESI/PI, an efficient homogenate model was developed, and four kinds of dopants (toluene, chlorobenzene, bromobenzene, and anisole) were tested using homogenate of mouse brain tissue as target sample. The influences of the dopants on the signal enhancements of different compounds were explained reasonably by the ionization mechanism. Then, the dopants with their optimum volume contents were applied to the mass spectrometry imaging (MSI). For a comprehensive imaging of various compounds with different polarities, methanol/toluene/formic acid (7:3:0.1) was chosen as the best choice. Finally, the stronger quantitative ability of DESI/PI with toluene as dopant for a few compounds in mouse brain tissue was demonstrated.
解吸电喷雾电离/后光致电离（DESI/PI）是一种新开发的电离方法，它将DESI与后光致电离相结合，用于生物组织中极性和非极性化合物的同时成像。掺杂剂在DESI/PI中非常重要，可通过离子-分子反应增强信号强度。在这项工作中，为了评估掺杂剂在DESI/PI中的性能，开发了一种有效的匀浆模型，并以小鼠脑组织匀浆为目标样品测试了四种掺杂剂（甲苯、氯苯、溴苯和苯甲醚）。通过电离机制合理地解释了掺杂剂对不同化合物信号增强的影响。然后，将具有最佳体积含量的掺杂剂应用于质谱成像（MSI）。为了对各种不同极性的化合物进行全面成像，选择甲醇/甲苯/甲酸（7:3:0.1）作为最佳选择。最后，证明了以甲苯为掺杂剂的DESI/PI对小鼠脑组织中几种化合物具有更强的定量能力。
