ИСТИНА

In the present work novel types of chitosan polyelectrolyte networks for SERS (surface enhanced Raman scattering) substrates were suggested both to protect superficial silver nanostructures and to concentrate an analyte as a donor and quinone acceptor (2,3-dichloro- 5,6-dicyano-1,4-benzoquinone, or DDQ) forming a charge - transfer complex to achieve superior enhancement of spectral data. Among other transparent polymers chitosan demonstrated no luminescence in the working region and did not suppress or shift much the plasmonic band position typical for naked silver SERS substrates. Moreover, SERS signal was successfully formed due to hydrophobic interactions between biopolymer macromolecules with the DDQ–DBT charge - transfer complex in nonpolar solvents such as diesel fuel.Furthermore, the chitosan biopolymer network also have other benefits since it can be crosslinked by simple chemical procedures to avoid its dissolving in hydrophilic liquids, also it can preconcentrate some urgent oil components due to its unique chemical properties and structure. Chitosan was used for the selective separation of DBT as an artificially designed tailored-made adsorbent through a molecular imprinting process. The proposed chitosancoated nanostructured silver SERS sensor allows to determine 5 – 1000 μM DBT in real fuel samples. Thus chitosan is the polymer of choice to form "smart" substrates for the analysis of sulphur - containing compounds by SERS.