title: Some new features of Direct Analysis in Real Time mass spectrometry utilizing the desorption at an angle option.
abstract: The present study is a first step towards the unexplored capabilities of Direct Analysis in Real Time (DART) mass spectrometry (MS) arising from the possibility of the desorption at an angle: scanning analysis of surfaces, including the coupling of thin-layer chromatography (TLC) with DART-MS, and a more sensitive analysis due to the preliminary concentration of analytes dissolved in large volumes of liquids on glass surfaces. In order to select the most favorable conditions for DART-MS analysis, proper positioning of samples is important. Therefore, a simple and cheap technique for the visualization of the impact region of the DART gas stream onto a substrate was developed. A filter paper or TLC plate, previously loaded with the analyte, was immersed in a derivatization solution. On this substrate, owing to the impact of the hot DART gas, reaction of the analyte to a colored product occurred. An improved capability of detection of DART-MS for the analysis of liquids was demonstrated by applying large volumes of model solutions of coumaphos into small glass vessels and drying these solutions prior to DART-MS analysis under ambient conditions. This allowed the introduction of, by up to more than two orders of magnitude, increased quantities of analyte compared with the conventional DART-MS analysis of liquids. Through this improved detectability, the capabilities of DART-MS in trace analysis could be strengthened.
authors.affiliation: Institute of Food Chemistry, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany. chern_es@mail.ru
authors.forename: Elena S
authors.initials: ES
authors.lastname: Chernetsova
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Revelsky
authors.forename: Gertrud E
authors.initials: GE
authors.lastname: Morlock