Intermolecular Interaction-Architected Functionalized SERS Interfaces for Rapid and Specific Sensing of Hydrazine

With the widespread application of hydrazine in industrial production, its potential health risks have become increasingly prominent. Thus, the development of on-site rapid monitoring technology for it has become especially important. Surface-enhanced Raman spectroscopy (SERS) has demonstrated exceptional potential for the rapid trace detection of contaminants in aqueous environments, owing to its high sensitivity, rapid response, and negligible interference from water. Herein, we constructed a novel highly sensitive sensing platform based on SERS technology to achieve on-site rapid detection of hydrazine in environmental water systems. This method integrates a portable Raman spectrometer with a functionalized SERS substrate modified by self-assembling p -mercaptobenzaldehyde molecules on the silicon-based Au film. Then, the aldehyde group of p -mercaptobenzaldehyde undergoes a specific condensation reaction with hydrazine to generate hydrazone compounds. This specific reaction shows significant changes in the SERS spectrum: the weakening of the C═O peak at 1693 cm –1 and the significant enhancement of the new characteristic C═N peak at 1655 cm –1 . This unique “fingerprint” spectral change provides direct evidence for the reaction process, thereby achieving highly selective and sensitive detection of hydrazine in water environments, with a detection limit as low as 1 ng/mL, far below the relevant standard limits for drinking water. This study successfully demonstrates a sensing strategy that integrates a specific chemical reaction with SERS signal transduction. The molecular-recognition-based design simultaneously affords high sensitivity and selectivity, offering a valuable paradigm for the development of rapid detection methods targeting other contaminants.