title: Separation of isomeric amines with ion mobility spectrometry.
abstract: Eight selected isomeric amines were ionized using atmospheric pressure chemical ionization and atmospheric pressure photoionization producing a protonated molecule [M+H](+) for each amine. The mobility of these ions was measured by ion mobility spectrometry. The amine compound class was shown to have an important role in mobility separation of the amines. 2,4,6-collidine, N,N-dimethylaniline and N-methyl-o-toluidine with highest observed mobilities have a N-heterocyclic aromatic ring, or are tertiary or secondary amines, respectively, whereas the rest of the compounds with lower mobilities were primary amines. It is suggested that the protonated -NH2 group (-NH3(+)) interacts more with the drift gas, and therefore the primary amines have lower mobilities. The effect of the drift gas was tested by mixing argon or helium with the nitrogen drift gas. The presence of argon shifted the mobilities towards lower values, while with helium the mobility shifted towards higher values. However, in neither case did this result in better separation of the unresolved compounds.
authors.affiliation: Federal University of Rio de Janeiro, Department of Chemistry, LAGOA-LADETEC, Ilha do Fundão, Rio de Janeiro, RJ 21941-909, Brazil; Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Finland. Electronic address: laakia@iq.ufrj.br.
authors.forename: Jaakko
authors.initials: J
authors.lastname: Laakia
authors.affiliation: Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, Finland.
authors.forename: Tiina J
authors.initials: TJ
authors.lastname: Kauppila
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Finland; Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, Finland.
authors.forename: Alexey
authors.initials: A
authors.lastname: Adamov
authors.affiliation: National Research Nuclear University MEPhI, Kashirskoe shosse 31, 115409 Moscow, Russia; Linantec Ltd., Kashirskoe shosse 31, 115409 Moscow, Russia.
authors.forename: Alexey A
authors.initials: AA
authors.lastname: Sysoev
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014, Finland; Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, FI-00014, Finland. Electronic address: tapio.kotiaho@helsinki.fi.
authors.forename: Tapio
authors.initials: T
authors.lastname: Kotiaho
mesh_terms: D000814:Aniline Compounds / Q000302:isolation & purification*; D001274:Atmospheric Pressure; D007477:Ions; D007536:Isomerism; D011522:Protons; D011725:Pyridines / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D000814:Aniline Compounds; D007477:Ions; D011522:Protons; D011725:Pyridines
keywords: Atmospheric pressure chemical ionization (APCI); Atmospheric pressure photoionization (APPI); Ion mobility spectrometry (IMS); Isomeric amines