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工学硕士学位论文基于表面增强拉曼光谱技术对三聚氰胺和硫氰酸钠的检测研究RESEARCHONDETECTIONOFMELAMINEANDSODIUMTHIOCYANATEUSINGSURFACEENHANCEDRAMANSPECTROSCOPY周宇哈尔滨工业大学2012年7月国内图书分类号：O443.4学校代码：10213国际图书分类号：53.37密级：公开工学硕士学位论文基于表面增强拉曼光谱技术对三聚氰胺和硫氰酸钠的检测研究硕士研究生：周宇导师：吕志伟教授申请学位：工学硕士学科、专业：物理电子学所在单位：光电子信息科学与技术系答辩日期：2012年7月授予学位单位：哈尔滨工业大学ClassifiedIndex:O443.4U.D.C:53.37DissertationfortheMasterDegreeinEngineeringRESEARCHONDETECTIONOFMELAMINEANDSODIUMTHIOCYANATEUSINGSURFACEENHANCEDRAMANSPECTROSCOPYCandidate：ZhouYuSupervisor：Prof.LuZhiweiAcademicDegreeAppliedfor：MasterofEngineeringSpeciality：Physical-ElectronicsAffiliation：Dept.ofOptic-electronicsInformationScienceandTechnologyDateofDefence：July,2012Degree-Conferring-Institution：HarbinInstituteofTechnology哈尔滨工业大学工学硕士学位论文摘要表面增强拉曼光谱技术（SERS）具有检测方便快捷，样品制备简单，对光源要求低等特点，使其成为食品检测领域的重要手段之一。随着社会的发展，人们对食品安全方面重视程度日益提高，但受于技术上的限制，某些食品添加剂仍只能通过传统化学检测方法进行实验室检测，检测成本高，检测周期长成为了限制其发展得主要原因。尤其在日常消费的乳制品行业中，非法添加剂的检测已成为迫切研究的问题。本论文提出通过对三聚氰胺和硫氰酸钠的拉曼光谱检测，分析两种物质的不同分子结构引起的拉曼频移，三聚氰胺由于环面内变形振动和环呼吸振动引起在676.8cm-1和984.6cm-1的特征峰；硫氰酸钠由C－S伸缩振动和C≡N的伸缩振动引起在756.9cm-1的峰和2069cm-1的特征峰。为了提高拉曼信号信噪比，论文中使用表面增强拉曼光谱技术，首先对表面增强剂和三聚氰胺水溶液和硫氰酸钠水溶液的不同混合比例进行了实验，首次通过计算建立了溶胶和溶液混合比例和特征峰强度的曲线，根据曲线获得了昀佳混合比范围。其次，对三聚氰胺水溶液、硫氰酸钠水溶液，三聚氰胺牛奶溶液以及硫氰酸钠牛奶溶液进行了光谱特性的分析。分析结果表明增强试剂、去离子水、牛奶等物质对三聚氰胺和硫氰酸钠的定性分析没有影响，但是由于牛奶中大分子成分的影响导致光谱图中信噪比有所降低。昀后，使用两种定量检测方法对三聚氰胺水溶液和牛奶溶液进行定量检测，并对两种方法得到的数据进行数据拟合。结果表明两种方法得到的检测结果相关性较高，对于光谱中没有内标峰的情况采用归一化法进行定量分析；当存在内标峰时使用内标法进行定量分析。并使用得到的标准曲线计算得到理论检测极限，三聚氰胺水溶液和三聚氰胺牛奶溶液分别为0.41ppm和1.64ppm。关键词：表面增强拉曼光谱技术；三聚氰胺；硫氰酸钠；表面增强剂昀佳混合比；定量分析；-I-哈尔滨工业大学工学硕士学位论文AbstractWiththesocialandeconomicdevelopment,thepublicismoreandmoreconcernedwiththesafetyoffood.Especiallyinthematterofmilkmarket,illegalfoodadditiveshavecreatedagreatproblemwhichneedstobesettleddownimmediately.However,somekindsoffoodadditivescanonlybeanalyzedbytraditionalchemicaltechnique.Thetraditionaltechniquehasthedefectionofhighcostandlongdetectionperiodwhichlimiteditsfurtherdevelopment.Inthecontrast,Surfaceenhancedspectroscopytechnology(SERS)hasmanyadvantages.It'seasyandquicktooperateandmakesamplesandithasalowrequirementoflaserlight.Forabovereasons,SERShasthepotentialtobecomeanadvancedmethodintheareaoffoodinspection.BythedetectionofmelamineandsodiumthiocyanateinRamanspectrum,WeanalyzedtheRamanshiftcausedbydifferentmolecularstructuresofthetwomattersinthearticle.Withthecharacteristicpeakofmelamineisconfirmedon676.8cm-1and984.6cm-1becauseofdeformationvibrationoutsideinplaneofringandtheringbreathingmode.InordertoimprovetheSNRofRamanspectrum,WeusedthetechniqueofSurfaceenhancedspectroscopy.FirstistoexperimentthedifferentblendingratiosofSERS-activesubstratesandMelaminesolutionandsodiumthiocyanatesolution.Second,bymakingspectralcharacteristicofmelaminesolution,sodiumthiocyanatesolution,melaminemilksolutionandsodiumthiocyanatemilksolution,WegottheanalysisresultswhichprovethatSERS-activesubstrates、deionizedwaterandmilkdon'thaveinterferenceinfluenceonthequalitativeanalysisofmelamineandsodiumthiocyanate.TheSNRdecreasesonlyinthetwoillegaladditivesmixedwithmilk,buttheextentofchangeiswithinthenationalstandardofPRC.Atlast,thespectroscopyofmelamineaqueoussolutionandmilkwasdetectedbytwokindsofquantitativedetectionmethods,thenweanalysedthetwokindsofdataandfittedit.Theresultsshowthatthetwomethodstogetresultsofthehighcorrelation,forthespectrumnointernalstandardpeakbythenormalizationmethodforthequantitativeanalysis;Whenthere'sinternalstandardpeakusingthestandardmethodwhenthequantitativeanalysis.Andthedetectionlimittheorywascalculatedbythestandardcurves,thedetectionlimitofmelaminesolutionandmelaminemilksolutionwere0.41ppmand1.64ppm.KeywordsSERS；Melamine；sodiumthiocyanate；ThebestratioofSERS-activesubstrates；determinationanalysis-II-哈尔滨工业大学工学硕士学位论文目录摘要...............................................................................................................................IAbstract.............................................................................................................................II第1章绪论....................................................................................................................11.1课题背景...............................................................................................................11.2研究的目的和意义...............................................................................................11.3国内外研究现状及分析.......................................................................................21.3.1拉曼光谱检测技术的研究现状....................................................................21.3.2奶制品中添加剂的检测方法研究现状........................................................41.4本课题研究的主要内容.......................................................................................6第2章拉曼光谱技术经典理论及三聚氰胺和硫氰酸钠特性研究............................72.1拉曼效应及其经典理论.......................................................................................82.1.1光散射原理....................................................................................................82.1.2拉曼效应产生原理.......................................................