20种氨基酸近红外光谱及其分子结构的相关性

发布时间：2018-04-11 15:36

本文选题：近红外光谱 + 氨基酸　；参考：《光谱学与光谱分析》2016年09期

【摘要】：旨在研究20种氨基酸的分子结构与其近红外光谱的相关性,为氨基酸近红外光谱在动物科学、食品和医药等方面的推广应用奠定一定的理论基础。应用岛津傅里叶变换红外光谱仪IRPrestige-21及其近红外附件FlexIRTM Near-Infrared Fiber Optics module,采集20种氨基酸标准物质在1 000~2 502nm波长范围内的近红外光谱,分辨率8cm-1,每个样品扫描3次,每次扫描50遍,取其平均值为氨基酸标准品的近红外光谱。根据氨基酸侧链基团的不同,分别比较脂肪族氨基酸、芳香族氨基酸和杂环氨基酸中各氨基酸分子结构与其近红外光谱的相关性。研究表明,20种氨基酸在1 000~2 502nm区域有非常明显的近红外光谱吸收且差异显著。分子量较大的脂肪族氨基酸其近红外光谱受侧链基团的影响较大,而甘氨酸近红外光谱受羧基和氨基的影响较大;两种芳香族氨基酸近红外光谱的差异主要来自于苯环,酪氨酸苯环上的—OH基团降低了苯分子的对称性,导致更多振动吸收峰的出现;杂环氨基酸因其侧链上杂环分子基团构成不同,其近红外光谱在1 600~1 800nm区域差异较大。综上,20种氨基酸主要存在4个特征光谱区:第1特征光谱区为1 050~1 200nm主要由C—H基团的二级倍频构成;第2特征光谱区为1 300~1 500nm主要由C—H基团的组合频构成;因侧链基团分子构成不同,在第3特征光谱区1 600~1 850nm和第4特征光谱区2 000~2 502nm表现出差异较大的特征吸收峰。因此,可以利用此4个近红外光谱特征区域对氨基酸进行定量和定性分析,提高氨基酸近红外光谱模型预测的准确性。
[Abstract]:The aim of this paper is to study the correlation between the molecular structure of 20 amino acids and their near infrared spectra, and to lay a theoretical foundation for the popularization and application of amino acid near infrared spectroscopy in animal science, food and medicine.IRPrestige-21 and its near infrared accessory, FlexIRTM Near-Infrared Fiber Optics module, were used to collect the near infrared spectra of 20 amino acid reference materials in the wavelength range of 1 000 ~ 2 502nm. The resolution was 8cm ~ (-1). Each sample was scanned 3 times, 50 times each time.The average value is the near infrared spectrum of amino acid standard.According to the differences of amino acid side chain groups, the correlation between the molecular structure of each amino acid in aliphatic amino acids, aromatic amino acids and heterocyclic amino acids and their near infrared spectra was compared.The results show that 20 amino acids have very obvious near infrared absorption in the region of 1 000 ~ 2 502nm and the difference is significant.The near infrared spectra of aliphatic amino acids with large molecular weight are greatly influenced by the side chain groups, while the near infrared spectra of glycine are greatly affected by carboxyl and amino groups, and the differences between the near infrared spectra of the two aromatic amino acids are mainly from benzene ring.The -OH group on the tyrosine benzene ring reduces the symmetry of benzene molecule and leads to more vibrational absorption peaks, and the near infrared spectra of heterocyclic amino acids vary greatly in the region of 1 600 ~ 1 800nm due to the heterocyclic molecular group composition on the side chain.There are four characteristic spectral regions in the 20 amino acids: the first characteristic region is 1 050 200nm, the second is composed of the second order frequency doubling of C-H group, the second characteristic region is 1 300 ~ 1 500nm mainly composed of the combined frequency of C-H group.Because of the different molecular composition of the side chain, the characteristic absorption peaks of 1 600-1 850nm in the third characteristic spectral region and 2 000 ~ 2 502nm in the fourth characteristic spectral region are different.Therefore, the quantitative and qualitative analysis of amino acids can be carried out by using these four NIR spectral characteristic regions to improve the prediction accuracy of NIR model of amino acids.
【作者单位】：云南农业大学动物科学技术学院云南省动物营养与饲料重点实验室;云南农业大学基础与信息工程学院;
【基金】：国家高技术研究发展专项(863计划)项目(2011AA100305) 云南省科技创新工程项目(2008LA020) 云南省应用基础研究计划面上项目(2011FB056)资助
【分类号】：O657.33;O629.71

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