Formation of anionic clusters of triols in the atmospheric pressure chemical ionization source: An ion mobility spectrometry and theoretical study

Abstract

Ionization of glycerol (Gly), triethanolamine (TEA), and tris(hydroxymethyl)aminomethane (Tris) was investigated in the negative mode of an atmospheric pressure corona discharge ion source by ion mobility spectrometry. It was found that ionization of the triols proceeds via both deprotonation and anion attachment. Thermodynamics of these reactions were studied in gas phase employing density functional theory using B3LYP and ωB97xD functionals. Chloroform and bromoform were used as dopants to produce alternative reactant ions Cl− and Br− in the ionization region. Because of the lower basicity of Cl− and Br−, the ionization mechanism of the triols was only halide attachment.