The very fast separation and identification of isomeric small substances with a molecular weight under 800 Da is still a challenge for high-throughput analysis. Inadequate chromatographic or spectrometric separation hampers an unequivocal identification of isomers, which may be recorded as a sum parameter. Reversed-phase liquid chromatography can be considered a generic method for the separation of isomers. However, a separation is usually achieved within minutes and not milliseconds as is typical for ion mobility spectrometry. The aim of this study, therefore, was to investigate the potential of IMS to separate small isomeric compounds. Hence, 23 substances divided into 11 isomeric groups have been selected. Among them, cancer drugs, hormones, pain relievers and others are contained. Three ion mobility spectrometers with different separation principles were compared with respect to their resolving performance. These systems comprised a traveling wave ion mobility spectrometer, a differential ion mobility spectrometer and a differential mobility analyzer. For reference, the chromatographic resolution and peak capacity was determined by high-performance liquid chromatography using a reversed phase.
Micro HPLC Generic method Ion mobility spectrometry Small molecules Isomeric separation
This is a preview of subscription content, log in to check access.
The authors would like to thank for financial aid support the German Federal Ministry for Economic Affairs and Energy within the agenda for the promotion of industrial cooperative research and development (IGF) on the basis of a decision by the German Bundestag. The access was opened by the German Federation of Industrial Research Association—AiF—and its member organisation Environmental Technology in short- member organization Environmental Technology (IGF Project No. 18861N). Special thanks to the technological SME SEADM, Dr. Marcus Winkler from Waters Corporation and Dr. Michael Schlüsener from the Bundesanstalt für Gewässerkunde for the kind opportunity to perform the resolution measurements on their systems. Additional thanks for the scientific exchange to Dr. Michaela Wirtz, Dr. Stefan Zimmermann and Dr. Terence Hetzel.
Compliance with ethical standards
Conflict of Interest
The authors declare that they have no conflict of interest.
European Commission (2015) Commission Implementing Regulation (EU) 2015/495 of 20 March 2015 establishing a watch list of substances for Union-wide monitoring in the field of water policy pursuant to Directive 2008/105/EC of the European Parliament and of the Council. Off J Eur Union L78/40:20–30. http://eur-lex.europa.eu/pri/en/oj/dat/2003/l_285/l_28520031101en00330037.pdf. Accessed 15 June 2018