Thermal desorption of inorganic compounds using hot-stage microscopy direct analysis in real-time mass spectrometry (HDM)

Ambient ionisation mass spectrometry methods have been routinely applied to organic materials; however, the literature covering the analysis of inorganic materials, particularly with plasma-based methods such as DART-MS, appears scarce. Here we report the use of the combined DART-MS and hot-stage microscopy technique termed HDM to the analysis of inorganic compounds, including salts, metal complexes and the in situ study of solvent-free metal–ligand complexing. The higher temperature capabilities of HDM allow for the analysis of these thermally stable compounds, observing temperature transitions higher than with conventional DART-MS analysis alone. Optical data collected using the integrated microscope are processed, and events such as melting, dehydration, degradation and thermochromism can be linked directly to the DART mass spectra.