Analysis of Volatile and Oxidation Sensitive Compounds Using a Cold Inlet System and Electron Impact Mass Spectrometry

Abstract

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The analysis of volatile and oxidation sensitive compounds by mass spectrometry is not easily achieved, as all state-of-the-art mass spectrometric methods require at least one sample preparation step, e.g., dissolution and dilution of the analyte (electrospray ionization), cocrystallization of the analyte with a matrix compound (matrix-assisted laser desorption/ionization), or transfer of the prepared samples into the ionization source of the mass spectrometer, to be conducted under atmospheric conditions. Here, the use of a sample inlet system is described which enables the analysis of volatile metal organyls, silanes, and phosphanes using a sector field mass spectrometer equipped with an electron impact ionization source. All sample preparation steps and the sample introduction into the ion source of the mass spectrometer take place either under air-free conditions or under vacuum, enabling the analysis of compounds highly susceptible to oxidation. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes, which have to be handled using inert conditions, such as the Schlenk technique. The principle of operation is presented in this video. Video LinkThe video component of this article can be found at

Multimodal Chemical Analysis of the Brain by High Mass Resolution Mass Spectrometry and Infrared Spectroscopic Imaging

“…41–45 The MALDI matrix 2,5-dihydroxybenzoic acid (DHB) is utilized industrially as an antioxidant 46, 47 and the vacuum created inside the ion source reduces oxidation during analysis. 48 This may be one of the first explorations of using these two imaging modalities, at their native optimal configurations, in which MS is performed first. Given the persistence of diagnostic information in IR imaging, despite the influence of various preparation conditions, 25, 49–51 it is likely that IR chemical signatures arise from robust structural features, and different regions of the brain are likely conserved post-MALDI analysis as well.…”

“…While MALDI MS is generally considered destructive, prior reports have shown that only a fraction of the sample is consumed during the measurement process . After single cell MALDI MS, sufficient material remains for follow-up analyses. , In imaging applications, tissue sections are frequently stained following MSI. − The MALDI matrix 2,5-dihydroxybenzoic acid (DHB) is utilized industrially as an antioxidant , and the vacuum created inside the ion source reduces oxidation during analysis . This may be one of the first explorations of using these two imaging modalities, at their native optimal configurations, in which MS is performed first.…”