Hydrogen Is\nthe Superior Nebulization Gas for Desorption\nand Electrospray Ionization

A previous comparative study between helium and nitrogen\nas nebulizing\nand desolvation gases in electrospray ionization (ESI) and desorption\nelectrospray ionization (DESI) found that the signal responses of\ncompounds of varying sizes and polarities were improved. Here, an\nexpanded selection of nebulizing gases was evaluated to investigate\nmechanisms of improvement. The set of nebulizing gases included hydrogen,\nhelium, nitrogen, argon, and carbon dioxide. Results indicate that\nthe signal enhancements are achieved by gases lighter than nitrogen\nand that the previously described helium effects can be improved by\nusing the more economical and sustainable hydrogen as a nebulizing\ngas. Additionally, H<sub>2</sub> and He reduce the desorption footprint,\nwhich could be potentially useful in increasing the resolution of\nchemical imaging microscopy, especially since, despite the smaller\nfootprint obtained using helium and hydrogen, higher signals are obtained\ncompared to nitrogen.