ИСТИНА

Surface Enhanced Raman Scattering (SERS) spectroscopy is a promising diagnostic tool because of its ultrasensitivity (as it provides label-free detection of molecules at very low concentrations) and specificity (as it allows identifying molecules by their vibrational fingerprint). However, problems with obtaining repeatable intensity of SERS-signal and overcoming extremely high values of S/N ratio in analysis of samples with complex matrices remain unsolved. One of the most baffling matrices is a diesel fuel. This report suggests a novel approach to SERS sample and surface pretreatment to obtain required repeatability and sensitivity of SERS-analysis by either surface or sample matrix modification with -acceptor. Our approach encompassing surface modification succeed in getting highly repeatable SERS-signal for polycyclic aromatic sulfur heterocyclic compounds (PASHs) which were absolutely ‘invisible’ previously. So, these molecules were ‘visualized’ by trapping into colored charge transfer complexes with the electron acceptors resulting in appearance of SERS-signal with a simple sample preparation step. Moreover, our novel strategy of sample pretreatment with -acceptor prior to SERS-analysis affords to minimize the S/N ratio by the separation of PASHs due to precipitation of other polyaromatic hydrocarbon components of fuel. The main feature of this stage consists in selection of appropriate -acceptor, e.g. 2,3-dichloro-5,6-dicyano-1,4-benzoquinone or 7,7,8,8-tetraquinodimethane for various PASHs as -donors. A significant contribution to the analysis is made by the way of performance of statistics calculations after analysis. Suggested approach was also used in the analysis of real diesel fuel.