TLC‐Freeze SERS: A Powerful Tool for Monitoring Synthetic Reactions

Thin layer chromatography (TLC) is widely used to confirm the formation of the target compound in chemical synthesis. The key issue in TLC is spot identification relying on retention factors. Coupling of TLC with surface-enhanced Raman spectroscopy (SERS), which gives direct molecular information, is a possible choice, to overcome this challenge. However, interference from the stationary phase and impurities on the nanoparticles added for SERS measurements significantly degrades TLC-SERS efficiency. We have found that freezing effectively eliminates such interferences and dramatically improves the performance of TLC-SERS. This study shows that TLC-freeze SERS is a powerful tool for monitoring essential organic reactions. This method can identify the product and side-products of similar structures, detect compounds with high sensitivity, and provide information of quantities that allows the reliable determination of the reaction time based on kinetic analysis.