Adsorption of functionalised thiols on gold surfaces: how to build a sensitive and selective sensor for a nitroaromatic compound?

Adsorption of thiols of varying structures bearing amine, acid or aromatic functionalities was characterised by Polarisation Modulation Infrared Absorption Spectroscopy (PM-IRRAS). The so functionalised surfaces were then submitted to atmospheres containing traces of 2,4-dinitrotrifluoromethoxybenzene and gas capture was evaluated by Quartz Crystal Microbalance (QCM). The selectivity of these new sensors was also evaluated thanks to exposures to solvents: ethanol, methylethylketone, toluene and dichloromethane. The QCM response appeared to be the best one, high and specific to the nitroaromatic, for aromatic amine functions

Nanoporous Membranes with Mixed Nanoclusters for Raman-Based Label-Free Monitoring of Peroxide Compounds

Monitoring trace amounts of peroxide-based molecules is challenging because of the lack of common optical signatures (fluorescence or absorption in UV-vis range) or chemical functionality easily detectable with common routines. To overcome this issue, we suggest a photochemical decomposition approach followed by the analysis of chemical fragments by a fast, sensitive, and reliable Raman spectroscopic method. To facilitate this approach, we employed a novel design of surface-enhanced Raman scattering (SERS)-active nanoporous substrate based on porous alumina membranes decorated with mixed nanoclusters composed of gold nanorods and nanoparticles. The detectable amount of HMTD below 2 pg demonstrated here is about 3 orders of magnitude lower than the current limit of detection. We suggest that laser-induced photocatalytic decomposition onto nanoparticle clusters is critical for achieving label-free detection of unstable and nonresonant organic molecules.close383