Detection of olefin vapours with silver(I)/cryptand-coated piezoelectric crystal sensors

A piezoelectric quartz crystal detector based on Ag+/cryptand-22/ethylenediamine/NH3/PVC coating with a computer interface for signal processing was prepared for olefin vapours, e.g. alkenes and alkynes. The silver(I)/cryptand-coated detector exhibited a high sensitivity with a frequency shift range of 10–350 Hz/(mg 1−1) for olefin vapours, a short response time with < 2 min, good selectivity and good reproducibility for reusage. The cryptand-22/Ag+ coating was sensitive for olefin vapours, but not for conventional alkyl polar organic molecules such as alkyl alcohols. Alkenes with a higher carbon number showed a better sensitivity than smaller alkenes and cis-alkenes exhibited a better response than trans-alkenes. Effects of temperature and interferences of water and alkyl sulfides were also investigated and discussed.