Our vacuum-compatible liquid micro jets can be adapted to mass spectrometers to study the interaction of biomolecules in water. Biomolecules undergo specific, non-covalent interactions with each other that determine their functionality. To study these effects of molecular recognition ultra-senstive methods are needed.

The challenge: How can biomolecules be removed from the water without destroying their ultra-weak interactions? The solution: Do not remove the biomolecules but remove the water! An IR laser, tuned to OH-stretch vibrations, instantaneously heats the water and leads to an explosive expansion of the jet. As the laser energy is only absorbed by the water, the biomolecules are released without being heated. Their weak interaction forces are not disturbed and can be studied. Due to the "chemical ionization" in water, the biomolecules and their aggregates are protonated. When dissolved from the water, they can be analysed via mass spectroscopy.