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

Cyclohexapeptides, which were bound covalently to an interference layer, were tested as new chemoreceptors for interaction with volatile organic compounds (VOCs) in the gaseous phase. For comparison, we have immobilized a linear hexapeptide on a quartz plate. The peptides consist of three or five L-amino acids as variable building blocks and are covalently attached with the 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 chemoreceptor layers was determined by reflectometric interference spectroscopy (RIfS). It was found that the affinity of the analytes for the cyclopeptides was higher than for the linear peptide. Cyclopeptides with different side chains showed distinct recognition patterns for different volatile organic compounds. The interaction was fast and reversible.