【作者】 贾廷见；

【导师】 莫育俊；

【作者基本信息】 河南大学 ， 光学， 2007， 硕士

【摘要】 中国名酒作为世界知名品牌,多年来一直受假名酒的侵害。如何区分和鉴别中国名酒,人们越来越关注。检验中国名酒的方法主要有两类:一类是采用感官品尝的方法,二是采用色谱分析的方法。但前者费时、费力、费物,限制其在工业生产及在流通领域的广泛应用。因此建立简单、快速的白酒品质鉴定方法,对于杜绝市场上出现的假冒劣质名优白酒具有重要意义。经过大量的研究发现:各香型的名优白酒中所含的香味成分种类几乎是相同的,但其量高低及它们之间的量比关系则不同。显然,对白酒中的数百种化学成分进行定量是不现实的也是没有必要的。只有对那些决定名白酒风味特征的化学性质稳定的成分进行定量才具有积极的意义。我们把这些组分及它们之间的量比关系综合称之为名白酒的“色谱骨架成分”。目前我国科研人员通过采用色谱-质谱、色谱-红外光谱联用,及其他先进的分析手段,分析了中国名优白酒30多种主要香味化学物质,根据这些香味成分的量比关系提出了名优白酒的“色谱骨架成分”是决定名优白酒的香型及质量特征的观点。这为白酒的香型确立与划分,寻求白酒之共性、鉴别各类白酒之差异,为白酒计算机勾调和作为白酒品评的一种补偿,利用计算机鉴别白酒优劣等等,提供了较为充分的依据。光谱分析法具有宏观整体鉴定复杂体系的优点以及无损快速的特点,目前已广泛应用于材料、化学、生物、矿物宝石、公安法学等研究领域。本文用紫外吸收光谱、红外光谱以及拉曼光谱对茅台酒进行了实验研究,目的在于找到它的色谱特征,以期对茅台酒的真假鉴定提供参考。我们通过对中国名酒的光谱分析研究发现,茅台酒中的糠醛含量是其它名酒的10倍左右。因此我们选择了糠醛作为研究对象,糠醛是茅台酒里最重要的香味成分之一。拉曼光谱和红外光谱都是研究分子振动的光谱方法,它们的原理和机制不同,但它们提供的结构信息却是类似的,都是关于分子内部各种简正振动频率及有关振动能级的情况,从而可以用来鉴定分子中存在的官能团。在分子结构分析中,拉曼光谱与红外光谱是相互补充的。因此,一些在红外光谱仪无法检测的信息在拉曼光谱能很好地表现出来。拉曼光谱和红外光谱相配合使用可以更加全面地研究分子的振动状态,提供更多的分子结构方面的信息。表面增强拉曼光谱对于痕量检测,具有很高的灵敏度,通常用来研究被检测样品吸附在金属表面时的构型变化,以及分子与金属表面的相互作用。密度泛函理论(Density Functional Theory)计算化学方法是近些年来发展起来的第三类电子结构方法(还包括半经验法和从头算方法),在计算时考虑到了电子交换能量和电子相关能量对结果的影响,使得计算结果比半经验方法和从头算方法更精确,而且其计算量小的多。目前它在化学、物理、生命科学、材料科学等领域的有广泛的作用。本论文对茅台酒的光谱进行了分析研究。主要内容有以下四部分组成:一:中国名酒的概述。即介绍了中国名酒的评定方法、成分、微量香味成分的研究历史、香型分类及主体香成分、中国名酒及糠醛的检测方法及取得的成果。并简单介绍了拉曼散射技术在无损检测技术新进展及表面增强拉曼散射的应用。二:茅台酒的光谱方法鉴别初探研究。我们分别用紫外吸收光谱法,红外光谱法,拉曼光谱法及表面增强拉曼光谱法对真假茅台酒进行了光谱研究。研究结果表明:用光谱法来鉴别茅台酒的真假是切实可行的。三:我们用密度泛函数理论计算出了糠醛分子的拉曼光谱和红外光谱,并将其与实验测得的糠醛分子的正常拉曼光谱和红外光谱进行比对,从而对糠醛分子的光谱振动模式进行了指认和归属。四:研究了糠醛分子吸附在银胶、银镜表面上的表面增强拉曼散射光谱。通过实验数据和密度泛函理论计算结果的比较分析,得出糠醛分子是以杂五环垂直于或稍微倾斜吸附表面的方向通过杂五环非键合的电子吸附到银颗粒表面的。同时,研究了糠醛在不同电压下,吸附在铜电极表面的SERS光谱,得出糠醛在铜电极表面的吸附方式随电极电压的改变而变化。更多还原

【Abstract】 The Chinese famous liquor, as the world-famous brand, has been receiving the infringement of the false famous brand all the time. Nowadays, people pay more and more attention to how to distinguish the Chinese famous brands of wine. There are mainly two kinds of methods to distinguish famous liquor: One method is to distinguish the liquor by the sense organ, and the other method is to adopt chromatograms analysis. But the former is time-consuming, arduous and costly, which limits its application in industrial production and circulation. Searching for simple and rapid appraisal method will be valuable in distinguishing high-quality Chinese liquor from fake or inferior brands.A large number of reports find: all kinds of Chinese famous liquor contain almost the same perfume components, but there are obvious differences between quantity and proportion of perfume. Obviously, it is unrealistic and unnecessary for quantitative analysis of several hundred kinds of chemical components in Chinese liquor. It is just significative for quantitative analysis of those perfume-decising compositions, which is chemically steady and determine the liquor flavor of the Chinese famous liquor. Chinese scientific researchers have analyzed the 30 kinds of main chemical components by GC/MS, GC/IR and other advanced analyzing methods. From the flavoring components of famous Chinese liquor, Chinese researchers put forward“chromatograph skeleton components”, which determine the aroma and quality of liquor. It provides potential evidence for the determination of aroma, commonness and differences of Chinese famous liquor. Also, it makes it feasible to blend and appreciate liquor by computer. Spectrum analytic approach has already applied to research fields such as material, chemistry, living beings, mineral gem, law sciences of public security for its fast and unharmful properties at present. This text has studied on the Moutai liquor by UV-Vis-NIR absorption, infrared and Raman spectra in order to obtain its chromatogram property and appreciate the true and false Moutai liquor. We find that the furfural content in Moutai is 10 times more than that of other famous brands of liquor by the spectral analysis, so we have chosen furfural, one of the most important perfume compositions in the Moutai, as the research object.Raman scattering is one method to investigate molecular vibrations. The principle and mechanism of Raman scattering is different from infrared spectrum, but the information they offer is complemental. They both offer information about various normal vibration frequencies and correlated vibrational energy level in the molecule. They can both be used to identify the functional group that exist in the molecule. In the analysis of molecular structure, Raman and infrared spectra supplement each other. As a result, some information that can’t be measured in infrared spectrum can well show in Raman spectrum. Raman spectrum is used along with infrared spectrum offer more comprehensive information of molecular structure. Surface enhanced Raman scattering, which has extremely high sensitivity and can offer molecular structure information, especially the information of mutual interaction between the molecules and metal surface, has been widely applied in trace detection. Density functional theory (DFT) is the third method (except ab initio method and semiempirical method ) of the computation of molecular structure and vibrational frequencies. DFT methods have led to the prediction of very accurate molecular structures and vibrational frequencies as compared to the conventional ab initio and semiempirical methods. The DFT method provides a costeffective approach for calculating the vibrational spectra of molecules. The DFT method has been extensively used in fields such as chemistry, physics, life sciences and material science at present.This paper has studied the spectrum of the Moutai liquor. The paper is made up of four parts as follows:One: summary of the Chinese famous brand of liquor. This part introduces appraisal method of famous liquor, component, micro-perfume composition, fragrant type, detection method and achievement of the Chinese famous brand and furfural made in the past. Also, we briefly introduce the application of Raman scattering and surface enhanced Raman technique in unharmful detection.Two: the elementary study on Moutai spectrum method is presented in this part. We investigated the true and false Moutai by UV-Vis-NIR, Raman and Surface enhanced Raman spectra method. The results show it is feasible for distinguishing the true and false Moutai by spectrum method.Three: We calculated the Raman and IR spectra of furfural molecule by DFT method and compare them with the normal Raman and infrared spectra obtained in our experiment. Also, the vibrational modes of spectra were assigned and ascribed. Four: this part investigated the furfural molecule absorded on the surface of silver colloid and silver mirror by surface enhanced Raman spectrum method. By the comparision analysis of the calculated and experimental results, it is concluded that furfural molecules are perpendicularity or acclivitously adsorded on the silver surface via the nonbonding electrons of the carbonyl oxygen. Meanwhile, we have studied SERS spectra of furfural molecule absorded on the surface of copper electrode under different voltages. The experimental results showed that the absorded manners of furfural molecule varied with change of the electrode voltage.更多还原