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.

Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography

“…Interfacing TLC plate analysis with mass spectrometry has been achieved through direct coupling using sampling probes with solvent elution [2], through direct electrospray ionization from physically modified plates [3], as well as through other commercially available ambient mass spectrometry techniques such as desorption electrospray ionization (DESI) [4][5][6] and direct analysis in real time (DART) [7][8][9]. A more complete picture of this landscape can be found in these reviews [10][11][12][13].…”

DART-Orbitrap MS: a novel mass spectrometric approach for the identification of phenolic compounds in propolis

“…The extracts were manually introduced into the ionization region using glass Dip-it sampling tips (IonSense). The analysis of DPS on HPTLC plates was performed using the DART angle of 30°and supplying the HPTLC plate into the ionization region with a motorized rail (IonSense) at the speed of 0.2 mm s −1 on a self-built stainless steel table [19].…”

Direct Analysis in Real Time Mass Spectrometry: a Powerful Tool for Fast Analysis

“…13 Generally, helium is used as work gas more often than argon and nitrogen for its higher energy of excited state. But, Cody and coworkers used argon as work gas to realize selective ionization of melamine and avoid interference from 5-hydroxymethylfurfural.…”