Study On The TiO₂ Surface Enhanced Raman Scattering Substrate For Drug Testing

Objective The purpose of this paper was to detect and analysis drug molecule 4-Mercaptobenzoic Acid?4-MBA? and Levofloxacin?LVFX? by using Raman and surfaceenhanced Raman scattering?SERS?. We deeply studied TiO₂ SERS-active substrate used for drug testing and explored the interactional mechanism between TiO₂ substrates and molecules. At the same time, we discussed the influence between drugs and substrates caused by other factors such as drug concentration, surface defect?surface state?, adsorption time and so on. This work was expected to be valuable for improving SERS performances of TiO₂ SERS-active substrate and its practical application.Methods We used sol hydrothermal method to achieve our goals, in which we added sulfuric acid to optimize TiO₂ nanoparticles, changed the calcination temperature and obtained diversified nanoparticles by adding other materials during the synthesis process, and characterized the nanoparticles. Compared the characteristic SERS signals of 4-MBA and LVFX with normal Raman. Analysised SERS signals which are obtained under the different parameters such as drug concentration, surface defect?surface state?, adsorption time etc. Study interaction between drugs and active substrate according the theoretical calculations.Results The results show that the SERS performances of TiO₂ NPs can be significantly improved by addition of H₂SO₄. The optimal amount of sulfuric acid was 0.14 ml. The detection limit can be reduced to 10-6 mol/L by SERS method. And, there is a good linear relationship in the range of 10-2-10-6 mol/L concentration, and a quantitative detection method of 4-MBA can be established. 4-Mercaptobenzoic acid?4-MBA? probe molecules exhibit different degree SERS enhancements on the surface of different phase structure TiO₂ nanoparticles. The mixed crystal structure TiO₂ is favourable to SERS enhancement of adsorbed molecules. The Levofloxacin?LVFX? molecules adsorbed on Zn-TiO₂ NPs exhibit the largest SERS enhancement, when the Zn content is 3%, the adsorption time is 7 h. The detection limit can be reduced to 10-7 mol/L by SERS method. And, there is a good linear relationship in the range of 1×10-3-1×10-7 mol/L concentration, and a quantitative detection method of LVFX can be established.Conclusions Raman and Surface-enhanced Raman spectroscopy are successfully used for detection and analysis of drug molecule. We provide a new analysis method for the detection of 4-Mercaptobenzoic Acid?4-MBA? and Levofloxacin?LVFX?. We also provide the references and laid a solid foundation for the analysis of drug molecules in the future. Study the further deep explores on the diversiform style high active substrates. This work is expected to be valuable for improving SERS performances of TiO₂ SERS-active substrate and its practical application.