Angew. Chem. Int. Edn doi:10.1002/anie.200902360 (2009)

Mass spectrometry is an invaluable tool for analysing substances' molecular compositions. But using it on viscous liquids such as toothpaste has required the time-consuming step of taking selective extracts from the liquids. Now these sticky complex mixtures can be monitored directly in a flask.

Renato Zenobi at the Swiss Federal Institute of Technology in Zurich and Huanwen Chen at the East China Institute of Technology in Fuzhou and their colleagues blew nitrogen gas through samples of toothpaste, honey and olive oil to create bubbles that carry molecules up to the sample's surface. There, the bubbles burst, creating aerosols that can be analysed in a standard mass spectrometer.

The team used the technique to track the progress of chemical reactions in viscous ionic liquids, which are increasingly popular solvents.