Preparation of QSS@AuNPs and Solvent Inducing Enhancement Strategy for Raman Determination of Salivary Thiocyanate

Making the substrates form highly dense, homogeneous, and stable hotspots regions is important for the sensitive detection of surface-enhanced Raman spectroscopy (SERS). A new strategy based on solvent-induced (SI) SERS substrate to form a stable interval of the hotspot for detection was explored and the enhancement factor (EF) of our SERS substrates could reach about 1.4 X 10(9). By preferential adsorption of alcohol solutions by Q-Sepharose microsphere (QSS) in mixed water and alcohol solutions, the size of QSS@AuNPs was dynamically adjusted and the spacing between gold nanoparticles (AuNPs) was adjusted to keep the substrate in the optimal hotspot mode for the sensitive detection of SERS in the liquid state. As a real application case, such a SI-SERS strategy was employed to determine SCN- in saliva and a limit of detection (LOD) of about 10(-10) M could be achieved.

Automated summary

The study explores a new strategy based on solvent-induced SERS substrates to form stable hotspots for sensitive detection. By preferential adsorption of alcohol solutions in mixed solutions, the spacing between gold nanoparticles was dynamically adjusted, achieving sensitive detection of SCN- in saliva with a detection limit of 10(-10) M.