Desorption Ionization by Charge Exchange (DICE) for Sample Analysis under Ambient Conditions by Mass Spectrometry

作者：Chan Chang Ching; Bolgar Mark S; Miller Scott A; Attygalle Athula B^*

来源：Journal of the American Society for Mass Spectrometry, 2010, 21(9): 1554-1560.

DOI：10.1016/j.jasms.2010.04.020

An ambient pressure ionization technique for mass spectrometric analysis of substances present on solid surfaces was developed. A nebulized spray containing molecular ions of a solvent such as toluene can be generated by passing the solvent through a stainless steel capillary held at a high voltage. When the stream of charged droplets produced in this way is directed onto a solid surface, the analytes present on the surface are desorbed and ionized by a charge exchange process. This technique was shown to desorb and generate positively charged molecular ions from compounds that are not readily ionized by some other ambient methods, under positive-ion generation mode. For example, intense signals representing radical cations of 1,4-hydroquinone, limonene, thymol, and several other compounds were observed when the analytes were deposited on a metal surface and exposed to a toluene spray nebulized from the metal capillary maintained at a potential of about +5 kV. In contrast, when the same samples were exposed to a spray of water/methanol/formic acid under customary DESI-like (positive-ion mode) conditions, no peaks representing the analytes were observed.

• 出版日期2010-9