Method Establishment And Application Exploration Of SERS Technique In Quantitative Analysis

Surface-enhanced Raman spectroscopy（SERS）is a detection technique that provides molecular fingerprint information and is widely used in the fields of materials analysis,biomedicine,food safety and environmental monitoring because of its high sensitivity,specificity and signal stability.Quantitative analysis is an important step in expanding the application of SERS technology in various fields,and is a hot topic in the field of SERS research and analytical chemistry,as well as a systematic scientific problem that needs to be solved.However,the development of SERS technology in the field of quantitative analysis is limited by the limitations of the conventional SERS substrates,such as low stability and poor signal reproducibility,as well as the inability to locate the molecule to be detected in the“hot spots”of the substrate.To address these issues,this thesis focuses on the“Method establishment and application exploration of SERS technique in quantitative analysis”with the following research:（1）In order to obtain SERS substrates with high sensitivity and uniformity that can provide stable and uniformly enhanced SERS signals,we have used our own UV holographic lithography system to prepare three-dimensional metal plasmonic array substrates and metal nano-gap array substrates that are uniform and tunable over a large area,respectively,and have achieved high sensitivity and uniformity of SERS substrates at multiple wavelengths（532 nm,633 nm,785 nm）by optimizing the metal materials and structural features.（2）In order to anchor DNA molecules that cannot form stable adsorptions directly to gold and silver to the strong local electromagnetic field region of the SERS substrate surface stably,direct label-free SERS detection of DNA molecules is achieved.We have developed a strategy for functionalized modification of the Au-HPOC substrate surface using poly（diene-dimethyl ammonium chloride）（PDDA）to achieve stable direct recognition of single base differences in DNA sequences and direct detection of DNA hybridization.（3）In order to achieve a sensitive and reliable quantification of Hg²⁺,which is metal cation without Raman signals,by SERS,we developed a strategy to quantify Hg²⁺concentrations in solution by a“turn-off”mechanism using rhodamine 6G molecule as Raman reporter.By introducing I^-into the detection system,the sensitivity of the quantitative detection of Hg²⁺concentrations were successfully improved.By combining this strategy with a high throughput SERS chip prepared by UV holographic lithography with excellent SERS performance and uniformity,the efficiency of the quantitative determination of Hg²⁺in solution was further enhanced and the quantitative determination of Hg²⁺in real samples was successfully achieved.