Study On Design And Synthesis Of Double Metal Doped TiO₂ SERS Active Substrates And Drug Detection

Objective Enrofloxacin?ENR?,a representative fluoroquinolone antibiotic,is widely used for the livestock breeding and aquaculture.The abuse of antibiotics is becoming more and more serious,and can result in a heavy drug residue in animal body and nature,which is seriously harming environment and people's health.Double metals?Zn and Ni?codoped strategy?simultaneously regulating metal doping level and surface state level?were carried out to further improve SERS activity of TiO₂ in this work.Moreover,the double metals codoped TiO₂ nanoparticles?NPs?were also served as SERS active substrate to detect the enrofloxacin?ENR?drug molecules for the first time.Methods The sol hydrothermal method was used in this paper,in the synthesis process different amounts of zinc nitrate and/or nickel nitrate were added into for improving the surface properties,and then the TiO₂ nanoparticles with different metal doping were prepared.The XRD,TEM,XPS test to characterize the property of the substrates.Drug intermediate molecular?4-MBA?was used as probe molecules to investigation the enhancement ability of double metal doped TiO₂,and the high SERS activity TiO₂ NPs were viewed as SERS substrate to detect enrofloxacin.The influence on ENR under various conditions?adsorption time,pH value,concentration?and the interaction of enrofloxacin and TiO₂ surface were also studied.Results In this work,Ni-Zn-TiO₂ nanoparticles were synthesized by sol hydrothermal method and used as SERS active substrates to detect the ENR drug molecules.The results show that this method of double metals doping can more improve SERS activity for TiO₂,the best SERS substrate is 1%Ni-1%Zn-TiO₂ whose enhancement factor can reach 1.3×104.The ENR is close to the TiO₂ surface through the carboxyl group.The optimal conditions are the adsorption time is 7 h and the pH value of adsorption solution is 7.04.Encouragingly,the minimum detectable concentration of ENR on the double metals codoped substrate?1%Ni-1%Zn-TiO₂?can be reduced to 1×10-9 M,and there is a good linear relationship in the concentration range of 1×10-4¹×10-9 M?y=21473.66+2306.42 C,R2=0.991?.The LOD of ENR on the 1%Ni-1%Zn-TiO₂ can be reduced to 3×10-10 M?corresponds to signal-to-noise ratio 3?.This work would be valuable for improving performance of TiO₂ SERS-active substrate and expanding its practical application.Conclusions According to the research results,we successfully improved the performance of SERS semiconductor TiO₂ and prepared high SERS activity of TiO₂.We make up the huge gap between semiconductor substrate and metal substrate in SERS enhancement ability,expanding the research scope of semiconductor TiO₂.The enrofloxacin detection research was carried out,and then the interaction relations of drug moleculars and TiO₂ substrate were deeply analysed.At the same time,we also carried out a qualitative and quantitative study of drug molecules to provide a theoretical and experimental foundation for application of SERS technology in drug detection.