This paper describes the detection
of volatile organic compounds (VOCs) using an e-nose type integrated
microfabricated sensor array, in which each resonator is coated with
different supramolecular monolayers: <i>p</i>-<i>tert</i>-butyl calix[8]arene (Calix[8]arene), 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine
(Porphyrin), β-cyclodextrin (β-CD), and cucurbit[8]uril
(CB[8]). Supramolecular monolayers fabricated by Langmuir–Blodgett
techniques work as specific sensing interface for different VOCs recognition
which increase the sensor selectivity. Microfabricated ultrahigh working
frequency film bulk acoustic resonator (FBAR) transducers (4.4 GHz)
enable their high sensitivity toward monolayer gas sensing which facilitate
the analyses of VOCs adsorption isotherms and kinetics. Two affinity
constants (<i>K</i><sub>1</sub>, <i>K</i><sub>2</sub>) are obtained for each VOC, which indicate the gas molecule
adsorption happen inside and outside of the supramolecular cavities.
Additional kinetic information on adsorption and desorption rate constants
(<i>k</i><sub>a</sub>, <i>k</i><sub>d</sub>) are
obtained as well from exponential fitting results. The five parameters,
one from the conventional frequency shift signals of mass transducers
and the other four from the indirect analyses of monolayer adsorption
behaviors, thus enrich the sensing matrix (Δ<i>f</i>, <i>K</i><sub>1</sub>, <i>K</i><sub>2</sub>, <i>k</i><sub>a</sub>, <i>k</i><sub>d</sub>) which can
be used as multiparameter fingerprint patterns for highly selective
detection and discrimination of VOCs
