CHIRAL DISCRIMINATION IN THE GAS-PHASE USING DIFFERENT TRANSDUCERS - THICKNESS-SHEAR MODE RESONATORS AND REFLECTOMETRIC INTERFERENCE SPECTROSCOPY

The discrimination of optical isomers (enantiomers) in the gas phase h as been performed using two different analytical tools: thickness shea r mode resonators (TSMRs) and reflectometric interference spectroscopy (RIFS). The selective coatings included both enantiomers ((S)- and (R )-receptor) of a Chirasil-Val derivative (stationary phase material in GC) with octyl side chains, Successful discrimination of the enantiom ers of different types of analytes (amino acids and lactates) was achi eved, The results of both transduction methods were consistent and in good agreement with GC measurements. In addition, different mixtures o f both enantiomers of the respective analyte were measured, and the en antiomeric composition could be quantitatively determined with excelle nt reliability, Since the sensors allow on-line monitoring (not possib le with GC) of enantiomeric purity, an application in industrial synth esis (process control) of such compounds represents an interesting fea ture, especially with regard to the tested derivatives of lactic acid.