Self-Assembly of L-Cysteine for Chiral Recognition of Mandelic Acid in Gas Phase

This study demonstrates a new approach for the selective recognition of chiral mandelic acid by quartz crystal microbalance (QCM) using L-cysteine as the selector. The modification of L-cysteine on the QCM sensor was identified using resonant frequency detection, the contact angle, cyclic voltammetry, and X-ray photoelectron spectroscopy measurements. The chiral recognizability of L- and D-MA on the L-cysteine-modified surface was examined using QCM detection integrated with a vapor diffused molecular assembly reaction technique. The present chiral recognition results suggest that the L-cysteine is a good resolving agent for detecting chiral mandelic acid.