SELECTIVE DETECTION OF NITROGEN AND OXYGEN-CONTAINING VOLATILE ORGANIC-COMPOUNDS - USE OF METAL-MODIFIED POLYSILOXANES AS SENSOR COATINGS

Polysiloxanes containing 3-heptafluorobutanoyl (Hfb) camphorates of me tal ions, e.g. zinc(II), nickel(II) and europium(III), have been used successfully as sensitive layers for thickness shear mode resonators ( TSMRs). These sensing layers provide pronounced selectivity in detecti ng volatile organic compounds (VOCs) in the gas phase and in particula r analytes containing heteroatoms, such as O and N. The selectivity re sults from co-ordinative binding between the electronically unsaturate d metal complexes and the heteroatom-containing analytes. This leads t o detection limits in the ng l(-1) (ppb)-range especially for nitrogen -containing compounds under conditions of slow but perfect reversibili ty.