【作者】 李毅；

【导师】 王嘉琛；

【作者基本信息】 华东师范大学 ， 无线电物理， 2020， 硕士

【摘要】 核磁共振技术具有便捷、直观、对样品无损等优点,被广泛应用于基础科学研究、医疗卫生诊断,以及工业生产检测等各领域。但是在对组分结构相似、性质相近的复杂样品体系的实际应用中,不同组分的磁共振信号会相互影响干扰,最终影响观测效果。本文探索采用不同磁共振新技术新方法,包括核自旋单态制备滤波技术和核磁共振指纹谱技术,解决磁共振方法在实际应用中,样品信号观测时间短,相似样品信号复杂难以区分等常见问题。对于样品中特定目标信号难以观测的问题,研究通过核自旋单态技术提高目标分子弛豫时间,从而改进观测效果。本研究首先以三肽AGG(Ala-Gly-Gly)分子为研究对象,分别使用SLIC、M2S以及优化脉冲三种单态制备序列,探究不同脉冲序列对AGG分子中二自旋体系单态制备效率的影响。随后采用SLIC脉冲制备研究了多巴胺分子中三自旋体系在不同浓度,以及多种有机物混合溶液条件及凝胶状态下的单态制备与观测效果,实现了对复杂有机混合物体系中多巴胺分子信号的特异性识别检测。而对含有大量组分相似性质相近的饱和或不饱和脂肪酸的植物性食用油,本研究尝试采用核磁共振指纹谱技术,设计新脉冲序列,采集建立植物油指纹谱的标准曲面,通过将不同植物油样品核磁信号与标准曲面进行比对,确定关键指纹识别区,并在此基础上实现对不同类型食用油,以及食用油掺杂掺伪的鉴别区分。更多还原

【Abstract】 Nuclear Magnetic Resonance（NMR）technology has been extensively applied in fundamental scientific research,medical diagnosis,manufacturing quality control and analysis,and other fields,with its advantages of convenient,straightforward and non-destructive to samples.However,in some case of complex samples,the NMR signals are overlapped and interacting with each other,therefore it leads to more complicated while less efficient data analysis,due to similar compositions and close structures of major components in the samples.In this paper,various novel methods of NMR,including nuclear spin singlet preparation and filtering technology,as well as NMR fingerprint technology,are explored to solve some practical problems in different applications of NMR.Application and manipulation of proton nuclear spin singlet states are studied for specifically observation of biomolecules in a complicated sample system.In our first project,three different nuclear spin singlet preparation sequences,including SLIC,M2S and optimal control pulses are used,using one of the two-spin system in tripeptide AGG as example,and their efficiency are compared and mechanisms behind this are discussed.Then we use SLIC pulse to further study the efficiency of observation for a three-spin system in dopamine molecule either for samples at different concentrations,or more complicated samples with other biomolecules.In the case of edible oils,which are composed of fatty acids with similar components and properties.We develop a magnetic resonance fingerprint spectroscopic with a set of new pulse sequence.With this method,NMR relaxation differences among different edible oils are amplified.Their T₂ distribution fingerprint regions and T₁-T₂correlation fingerprint regions have been used for identification of different oil samples.It has been demonstrated that this method is efficient in identification of oil samples of different types,or samples adulterated with either water,fried oil,lard or butter.更多还原