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Investigations of cluster ions formed between cesium cations and benzoic, salicylic and phthalic acids by electrospray mass spectrometry and density‐functional theory calculations. Toward a modeling of the interaction of Cs + with humic substances
Author(s) -
Maria PierreCharles,
Gal JeanFrançois,
Massi Lionel,
Burk Peeter,
TammikuTaul Jaana,
Tamp Sven
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1818
Subject(s) - chemistry , phthalic acid , electrospray , benzoic acid , adduct , salicylic acid , density functional theory , mass spectrometry , inorganic chemistry , stoichiometry , molecule , ion , phenol , computational chemistry , organic chemistry , chromatography , biochemistry
A concerted theoretical (density‐functional theory) and experimental electrospray mass spectrometry study was conducted on the formation of cesium cation adducts with small molecules taken as models of specific interactions sites in humic substances. Electrospray experiments with phenol, benzoic acid, salicylic acid, and phthalic acid, in methanolic solution containing cesium nitrate, were performed using a quadrupole ion trap. The formation of positively charged mixed clusters, [Cs(CsNO 3 ) n (CsA 1 ) m (Cs 2 A 2 ) p ] + (A 1 = benzoate, salicylate, and hydrogenophthalate, A 2 = phthalate), was observed. Calculations of structures and bonding energetics of Cs + in simple adducts formed with NO 3 − , CsNO 3 , A − , AH, and CsA are reported. The observation of variable cluster stoichiometry (n, m and p values) was interpreted in terms of more or less favorable interaction energies between Cs + and the neutral species constituting the clusters. Phenol did not form clusters in significant abundances, despite a strong calculated interaction between Cs + and cesium phenolate. This was attributed to its weak acid dissociation in the electrospray solution. Copyright © 2005 John Wiley & Sons, Ltd.