【讨论】问一个活泼氢交换问题

yes, vacuumm is crucial for MS coze the gas molecular ion will fly and hit the detector according Newton equation assuming the analyte ion will not change its travel trajectory during its flight. therefore ion shoud be free from collision with other non-analyte ions. the only way to deal with it is to use vacuume to get most of other gas molecules out of chamber of MS. Based on the Bolzemann theory, once the analyte flight distance is shorter than the free-flight-distance, the chance of analyte ion collides with other ions is low.
This is the whole idea why use vaccumm in MS. Man!

换DMSO做溶剂

核磁检测不必太在意活泼氢. 一般是看 C-H 了解骨架结构.