Division of Macromolecular Chemistry, Institute of Applied Synthetic Chemistry, Vienna University of Technology, 1060 Vienna, Austria.
Division of Macromolecular Chemistry, Institute of Applied Synthetic Chemistry, Vienna University of Technology, 1060 Vienna, Austria.
Carbohydr Polym. 2019 Jan 15;204:124-130. doi: 10.1016/j.carbpol.2018.10.003. Epub 2018 Oct 4.
The purpose of the present study was the development of an accurate method to determine the degree of substitution (DS) of modified hyaluronic acid (HA) by proton nuclear magnetic resonance (H NMR) spectroscopy. The influence of the effect of ionic strength and pH on H NMR spectra of HA was studied. The results showed a correlation between the conformation of HA in solution and the quality of the H NMR spectra. The best spectra with full proton mobility are obtained when HA is dissolved in DO with 2 M NaCl or DO with 0.1 M NaOD with a maximum concentration of 5 mg/ml. Under those conditions the size of the polymer coils is reduced below the concentration of chain overlap point, all the protons show the same response and a correct degree of substitution can be determined.
本研究的目的是开发一种准确的方法，通过质子核磁共振（H NMR）光谱法来确定修饰透明质酸（HA）的取代度（DS）。研究了离子强度和 pH 值对 HA 的 H NMR 光谱的影响。结果表明，HA 在溶液中的构象与 H NMR 光谱的质量之间存在相关性。当 HA 在 2 M NaCl 的 DO 或 0.1 M NaOD 的 DO 中以最大浓度 5 mg/ml 溶解时，可获得具有完整质子迁移率的最佳光谱。在这些条件下，聚合物线圈的大小减小到链重叠点的浓度以下，所有质子都表现出相同的响应，并且可以确定正确的取代度。
