[Absolute quantification of carminic acid in cochineal extract by quantitative NMR].
[Absolute quantification of carminic acid in cochineal extract by quantitative NMR].
复制标题
[通过定量NMR对胭脂虫红提取物中胭脂红酸进行绝对定量]。
DOI：
10.3358/shokueishi.51.19
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
T. Nishimura
中科院分区：
文献类型：
--
作者：
N. Sugimoto;A. Tada;T. Suematsu;Kazunori Arifuku;Takeshi Saito;T. Ihara;Yuuichi Yoshida;R. Kubota;Maiko Tahara;K. Shimizu;S. Ito;T. Yamazaki;Y. Kawamura;T. Nishimura
应用定量NMR（qNMR）方法测定胭脂红酸。胭脂红酸是胭脂虫红染料的主要成分，胭脂虫红染料是一种广泛使用的天然食品着色剂。由于几家制造商仅提供试剂级胭脂红酸，因此没有确定纯度的参比物质。为了提高分析数据的可靠性，我们正在开发定量核磁共振（qNMR），这是基于给定NMR共振的强度与样品中该核的摩尔量成正比的事实。胭脂红酸的纯度和含量由胭脂红酸上的芳香族质子与用作内标的DSS-d 6上的三个甲基的九个质子的信号强度的比率计算。使用邻苯二甲酸氢钾校正DSS-d 6本身的浓度，邻苯二甲酸氢钾是一种经认证的参比物质（CRM）。以胭脂红酸钾盐三水合物的晶体结构为基础，测定了胭脂红酸钾盐三水合物的纯度和胭脂红酸含量，并通过X射线衍射分析证实了这一点，其SI-溯源性分别为25.3-92.9%和4.6-30.5%。的qNMR方法不需要参考化合物，是快速和简单的，只有10分钟的总分析时间。因此，我们的方法代表了一个绝对的定量方法与SI的可追溯性，应该很容易适用于任何天然产物的分析和质量控制。
A quantitative NMR (qNMR) method was applied for the determination of carminic acid. Carminic acid is the main component in cochineal dye that is widely used as a natural food colorant. Since several manufacturers only provide reagent-grade carminic acid, there is no reference material of established purity. To improve the reliability of analytical data, we are developing quantitative nuclear magnetic resonance (qNMR), based on the fact that the intensity of a given NMR resonance is directly proportional to the molar amount of that nucleus in the sample. The purities and contents of carminic acid were calculated from the ratio of the signal intensities of an aromatic proton on carminic acid to nine protons of three methyl groups on DSS-d6 used as the internal standard. The concentration of DSS-d6 itself was corrected using potassium hydrogen phthalate, which is a certified reference material (CRM). The purities of the reagents and the contents of carminic acid in cochineal dye products were determined with SI-traceability as 25.3-92.9% and 4.6-30.5% based on the crystalline formula, carminic acid potassium salt trihydrate, which has been confirmed by X-ray analysis. The qNMR method does not require a reference compound, and is rapid and simple, with an overall analysis time of only 10 min. Our approach thus represents an absolute quantitation method with SI-traceability that should be readily applicable to analysis and quality control of any natural product.