高等学校化学学报 ›› 2019, Vol. 40 ›› Issue (1): 47-54.doi: 10.7503/cjcu20180421

• 分析化学 • 上一篇    下一篇

黄豆黄素与黄豆黄苷吸收光谱和荧光光谱的比较研究

李文红1, 王丹阳2, 曹津津2, 魏永巨2()   

  1. 1. 河北工业职业技术学院环境与化学工程系, 石家庄 050091
    2. 河北师范大学化学与材料科学学院, 石家庄 050024
  • 收稿日期:2018-06-08 出版日期:2019-01-10 发布日期:2018-11-16
  • 作者简介:

    联系人简介: 魏永巨, 男, 博士, 教授, 主要从事天然荧光产物和荧光分析方面的研究. E-mail: weiyju@126.com

  • 基金资助:
    国家自然科学基金(批准号: 20975029, 81173496)、 河北省科技计划自筹项目(批准号: 17273003)和河北工业职业技术学院博士基金(批准号: BZ201701)资助.

Comparative Study of Absorption and Fluorescence Spectra of Glycitein and Glycitin

LI Wenhong1, WANG Danyang2, CAO Jinjin2, WEI Yongju2,*()   

  1. 1. Department of Environmental and Chemical Engineering, Hebei College of Industry and Technology, Shijiazhuang 050091, China
    2. College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024, China
  • Received:2018-06-08 Online:2019-01-10 Published:2018-11-16
  • Contact: WEI Yongju E-mail:weiyju@126.com
  • Supported by:
    † Supported by the National Natural Science Foundation of China(Nos.20975029, 81173496), the Science and Technology Program of Hebei Province, China(No.17273003) and the Doctoral Fund Project of Hebei College of Industry and Technology, China(No.BZ201701).

摘要:

研究了黄豆黄素和黄豆黄苷在不同pH条件下的吸收光谱和荧光光谱, 从分子结构的角度解释了二者呈现不同光谱特征的原因. 黄豆黄素分子基本无荧光. 在弱碱性时, 黄豆黄素分子发生7-OH质子的电离, 导致吸收光谱中320 nm的吸收峰红移至348 nm. 采用pH-光度法测得7-OH质子的电离常数pKa1=7.08±0.04. 黄豆黄素一价阴离子呈现较强荧光, 最大激发和发射波长λex/λem分别为334 nm/464 nm, 荧光量子产率为0.049. 在碱性溶液中, 黄豆黄素4'-OH质子电离, 导致吸收光谱中254 nm的吸收峰红移至260 nm, 电离常数pKa2=9.96±0.01. 黄豆黄苷分子基本无荧光. 在碱性条件下, 黄豆黄苷分子的4'-OH质子发生电离, 导致吸收光谱中256 nm的吸收峰红移至 280 nm, 电离常数pKa=9.81±0.03. 黄豆黄苷阴离子基本无荧光, 但在热碱性条件下发生γ-吡喃酮环裂解反应而产生较强荧光, λex/λem为288 nm/388 nm, 裂解产物的荧光量子产率为0.056. 虽然, 黄豆黄苷与黄豆黄素是苷与苷元的关系, 但黄豆黄苷不能在热碱性条件下通过糖苷水解转变为黄豆黄素, 二者的荧光增强机理存在本质不同.

关键词: 异黄酮, 黄豆黄素, 黄豆黄苷, 裂解反应, 荧光增强

Abstract:

The absorption and fluorescence spectra of glycitein and glycitin in aqueous solutions with different pH values were investigated in detail, and the reasons why the two presented different spectral characteristics were explained in the viewpoint of molecular structure. The molecular form of glycitein is essentially no fluorescence. Under weak alkaline condition, the 7-OH proton ionization causes a redshift of the absorbance peak at 320 nm to 348 nm. The proton ionization constant is measured to be pKa1=7.08±0.04, by a pH-photometric method. The univalent-anion form of glycitein exhibit a fairly strong fluorescence with maximum excitation and emission wavelengths(λex/λem) of 334 nm/464 nm, and the fluorescence quantum yield is measured to be 0.049. In alkaline solutions, the ionization of 4'-OH proton of glycitein causes a redshift of the absorbance peak at 254 nm to 260 nm, the ionization constant is pKa2=9.96±0.01. The molecular form of glycitin has almost no fluorescence. Under alkaline conditions, the ionization of 4'-OH proton causes a redshift of the absorbance peak at 256 nm to 280 nm, with pKa=9.81±0.03. The anion form of glycitin has almost no fluorescence, but the cleavage reaction of γ-pyrone ketone ring occurs under hot and alkaline conditions and produces a fairly strong fluorescence, with λex/λem of 288 nm/388 nm, and the fluorescence quantum yield of the cleavage reaction product is 0.056. Although the relationship between glycitin and glycitein is as that of glycoside and aglycone, but glycitin cannot be converted to glycitein by means of hydrolysis of glycoside under hot alkaline conditions. The fluorescence enhancement mechanisms of these two are essentially different.

Key words: Isoflavone, Glycitein, Glycitin, Cleavage reaction, Fluorescence enhancement