MASS-SENSITIVE DETECTION OF SOLVENT VAPORS - MECHANISTIC STUDIES ON HOST-GUEST SENSOR PRINCIPLES BY FT-IR SPECTROSCOPY AND BET ADSORPTION ANALYSIS

Chemical sensors based on highly mass sensitive QCM or SAW devices, co ated with sensitive layers, are especially suited for the trace analys is of organic soh ent vapors, such as halogenated or aromatic hydrocar bons. The paracyclophanes B44TOS and CP44 were used as sensitive coati ngs, employing the principles of host-guest chemistry, The application of the BET model to the incorporation of chloroform in the sensitive coatings proves intracavitative complexation according to a 1:1 stoich iometry. Beyond the mass-sensitive detection, the complexation was stu died by FT-IR spectroscopy. The exhibited saturation behavior of the c haracteristic CDCl3 bands confirms the results of the mass-sensitive m easurements, The lowering of the C-D stretching frequency was compared with the shifts caused by several model compounds, such as N-butylani line, All results described indicate the formation of host-guest compl exes between chloroform and paracyclophanes.