Journal article
Gas phase salt clusters from electrosprayed alkaline earth colloids
International journal of mass spectrometry and ion processes, Vol.162(1-3), pp.107-119
03/01/1997
DOI: 10.1016/S0168-1176(96)04515-6
Abstract
Several distributions of small polynuclear ions of general form [nM + mA + pS]q+ (where M represents an alkaline earth cation (Mg, Ca, Sr or Ba), n = 2–10, A represents a halide, acetate or nitrate counterion originating in the divalent salt, and S represents an acetic acid or methanol adduct) are detected by FTICR when water/methanol solutions of alkaline earth salts are electrosprayed. For example, the largest cluster ion derived from 6.3 mM solutions of calcium acetate acidified with 2%x acetic acid have n= 10, m = 18, p = 5 and q = 2. Characteristics of these solutions suggest the presence of colloidal dispersions. These characteristics include stability upon aging, light scattering response and the requisite pre-etching of the glass containers. Aqueous mixtures of two group II salts produce mixed-salt cluster ions. For instance, from a mixture of calcium and magnesium acetate we trap mixed-cation clusters characterized by a complete set of binary partitions of n, for n = 2–6. Specifically, the manifold of clusters with four cations contains 4:0, 3:1, 2:2, 1:3 and 0:4 ratios of magnesium to calcium. Isolated alkaline earth clusters react with a low-pressure background of 18-crown-6 (C6) by salt abstraction exclusively. In general, the more facile abstraction from a mixed cluster produces a pair of products in which the neutral conforms to the hard-soft acid-base principle. The reactions of C6 with [MgSr(OAc)3]+ provide evidence for the existence of isomeric clusters at m/z 289. This is supported by bimodal kinetics and preliminary results of ab initio calculations.
Details
- Title: Subtitle
- Gas phase salt clusters from electrosprayed alkaline earth colloids
- Creators
- R. Marshall Pope - Brigham Young UniversityNanzhu ShenJeremy Nicoll - Brigham Young UniversityBoris Tarnawiecki - Brigham Young UniversityChadin Dejsupa - Brigham Young UniversityDavid V. Dearden - Brigham Young University
- Resource Type
- Journal article
- Publication Details
- International journal of mass spectrometry and ion processes, Vol.162(1-3), pp.107-119
- DOI
- 10.1016/S0168-1176(96)04515-6
- ISSN
- 0168-1176
- eISSN
- 1873-2801
- Language
- English
- Date published
- 03/01/1997
- Academic Unit
- Medicine Administration
- Record Identifier
- 9984627253102771
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