Interaction between volatile organic compounds and cyclopeptides detected with reflectometric interference spectroscopy

Cyclohexapeptides, which were bound covalently to an interference layer, we re tested as new chemoreceptors for interaction with volatile organic compo unds (VOCs) in the gaseous phase. For comparison, we have immobilized a lin ear hexapeptide on a quartz plate. The peptides consist of three or five L- amino acids as variable building blocks and are covalently attached with th e amino group in the side chain of L-lysine residues to the quartz surface. Spectroscopic ellipsometry was used to investigate the physical thickness of the peptide layer. The interaction between the analytes and the chemorec eptor layers was determined by reflectometric interference spectroscopy (RI fS). It was found that the affinity of the analytes for the cyclopeptides w as higher than for the linear peptide. Cyclopeptides with different side ch ains showed distinct recognition patterns for different volatile organic co mpounds. The interaction was fast and reversible. (C) 1999 Elsevier Science B.V. All rights reserved.