Applications Of SERS Technique In Combination With Multiplicative Effects Model To Quantitative Qnalysis Of Complex Systems

Surface-enhanced Raman spectroscopy(SERS)has the advantages of simple sample preparation,fast analysis,and high sensitivity etc.,it has been increasely used in the field of analytical chemistry.However,when using SERS technique to quantitatively analyze complex systems,the obtained SERS spectral data contains not only the spectral information of the target analyte but also interfering signals caused by the variations in samples' physical properties,measurement conditions,and background intereferences as well.In order to realize the direct,rapid and accurate SERS quantitative analysis of the target components in complex systems,a novel multivariate calibration model-multiplicative effects model(MEM)has been proposed by our research group.MEM model can effectively eliminate the deterimental effects caused by varaitons in interfering factors,and solve some tricky problems in the SERS quantitative analysis of target components in complex systems.The main contents of this thesis include the following aspects:In Chapter 2,SERS technique in combination with MEM model was applied to the quantification of methimazole in plasma and tablet samples.Experimental results showed that MEM model could eliminate detrimental effects caused by variations in the physical properties of enhancing substrate,the intensity and alignment/focusing of laser excitation source,and realized the accurate quantitative determination of methimazole in plasma and tablet samples.The average relative predictive error of MEM model for methimazole in plasma samples was 5.1%.The limit of detection was estimated to be 32.1 nM.The recovery rates of MEM for methimazole in tablet samples were in the range of 93.3%?110.9%,comparable to the corresponding values of LC-MS/MS experiments.In Chapter 3,a SERS quantitative method based on a generalized ratiometric indictor was proposed to detect Cd2+ in rice samples.A brief procedure of the method is as follows:1),SERS enhancing substrate for SERS quantification of Cd2+ was fabricated by modified Au nanoparticles with trithiocyanuric acid(TMT)which can chelate Cd2+;2)a drop of mixture solution of SERS enhancing sudbstrate and the sample to be analyzed was dripped into the holes of the conical holed glass substrate to obtain the SERS spectra of both the standard sanples and the test samples;3)The MEM model was built on the SERS spectra of the standard samples and then used to quantitative analyze the SERS spectra of rice samples.This method extended the MEM model from simple water detection to more complex rice systems,which reflected the broadness of MEM model.O-phenylenediamine has no obvious SERS signal on the surfaces of silver nanoparticles modified with ?-cyclodextrin.Nevertheless,o-phenylenediamine can react with nitrite(NO2-)to produce benzotriazole under acidic conditions which can enter into the hydrophobic cavity of a-cyclodextrin on the surfaces of silver nanoparticles and produce a strong SERS signal.In Chapter 4,this phenomenon in combination with MEM model was used to quantitatively analyze NO2-in environmental water samples,and achieved quite accurate quantitative results comparable to those obtained by high performance liquid chromatography.