title: Desorption ionization by charge exchange (DICE) for sample analysis under ambient conditions by mass spectrometry.
abstract: 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.
authors.affiliation: Center for Mass Spectrometry, Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA.
authors.forename: Chang-Ching
authors.initials: CC
authors.lastname: Chan
authors.forename: Mark S
authors.initials: MS
authors.lastname: Bolgar
authors.forename: Scott A
authors.initials: SA
authors.lastname: Miller
authors.forename: Athula B
authors.initials: AB
authors.lastname: Attygalle
mesh_terms: D001274:Atmospheric Pressure; D053138:Cyclohexenes / Q000032:analysis / Q000737:chemistry; D006873:Hydroquinones / Q000032:analysis / Q000737:chemistry; D000077222:Limonene; D009330:Nebulizers and Vaporizers; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013193:Stainless Steel / Q000737:chemistry; D013729:Terpenes / Q000032:analysis / Q000737:chemistry; D013943:Thymol / Q000032:analysis / Q000737:chemistry
chemical_list: D053138:Cyclohexenes; D006873:Hydroquinones; D009930:Organic Chemicals; D013729:Terpenes; D013193:Stainless Steel; D013943:Thymol; D000077222:Limonene; C031927:hydroquinone