I'd like to know what a piezoelectric sorption detector is. I can hardly find information about, only a small number of research papers which are mostly not accessable for me.
Only given from the term I cannot really imagine its functionality.
The resonance frequency of a piezo-electric "tuning fork" is influenced by the mass of adsorbed molecules.
I know this kind of instruments as piezo thickness monitors when evaporating metals in vacuum equipment. They can be very sensitive.
Edit: there is a long article on Wikipedia. I did not read it all but it explains how this works. https://en.wikipedia.org/wiki/Quartz_crystal_microbalance
Edit 2: Such a piezoelectric resonator can be functionalized for sorption with a coating as described in 1964 by King in his article "Piezoelectric sorption detector"