title: Secondary ion emission from solutions: time dependence and surface phenomena.
abstract: The temporal behavior of FAB mass spectra from glycerol solutions of tetradecyltrimethylammonium bromide (C14H29-N(CH3)3Br, TTAB) and tetraethylammonium iodide (TEAI) was investigated. FAB spectra of the TTAB solution displayed a continuous decrease in TTA+ with time. Spectra obtained from the TEAI solution were initially invariant for several minutes and then displayed a gradual increase in the relative abundance of TEA+ to a maximum, followed by a precipitous drop in ion intensity. Secondary ion images of droplets of TTAB solution showed that emission of both TTA+ and glycerol secondary ions was homogeneous across the sample. Secondary ion images of droplets of TEAI solution showed heterogeneous and segregated emission of both TEA+ and protonated glycerol. Results from the FAB spectra and the secondary ion images were correlated and rationalized on the basis of surface tension-induced mass transport and matrix evaporation.
authors.affiliation: Department of Chemistry, University of Tennessee, Knoxville 37996-1600.
authors.forename: M S
authors.initials: MS
authors.lastname: Kriger
authors.forename: K D
authors.initials: KD
authors.lastname: Cook
authors.forename: R T
authors.initials: RT
authors.lastname: Short
authors.forename: P J
authors.initials: PJ
authors.lastname: Todd
mesh_terms: D007477:Ions; D013058:Mass Spectrometry; D012996:Solutions; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013499:Surface Properties; D013997:Time Factors
chemical_list: D007477:Ions; D012996:Solutions