Hybrid Au/CNT systems: a novel breakthrough for enhanced Raman sensing of nitrile-based organic solvents.

This work deals with the preparation of carbon nabotube (CNT) deposits decorated with gold nanoparticles, and the use of Surface Enhanced Raman Spectroscopy (SERS) related to the strong plasmon absorption of gold for the detection of cyanide groups. Au nanoparticles with controlled sizes are produced by electrochemical techniques onto ensambles of CNTs deposited from hexane in N2 atmosphere. The synthesis methodologies employed to produce these hybrid materials assure an excellent adhesion to the substrate, avoiding hazardous dispersion of the nanocomponents. The use of Raman spectroscopy in the 2150-2350 cm(-1) frequency range enables to detect the presence of nitrilebased organic solvents and to discriminate between different organic cyanides. The response of the Au/CNT systems contacting nitrile-based solvents is characterized by good sensitivity, selectivity, reversibility and stability. The proposed methodology can detect in real time low levels of organic solvents and of other chemicals able to interact with gold, also in flowing systems and without stringent sample-volume requirements.