impurity 1 and impurity 2, detected after acid hydrolysis of moxidectin (impurity 2 was also observed to a lesser extent after oxidation), were isolated from sample matrices and identified using liquid chromatography, NMR, high-resolution FT-ICR MS, and hydrogen/deuterium exchange studies. FTMS ...
青岛科技大学 硕士学位论文 肝素钠中主要杂质的NMR定量分析方法及污染肝素的分离技术研 究 姓名:*** 申请学位级别:硕士 专业:无机化学 指导教师:**强;张玉冰 20120606 肝素钠中主要 NMR分析方法及㈣ 染肝素的分离技术研究 摘要 肝素钠(HeparinSodium,HP)是从猪小肠粘膜中提取出来的一种糖胺聚糖 类抗凝血药物,具...
When the method was transferred to the determination of different kinds of samples, the most significant issue was signal overlapping of impurity signals, which affected the method’s accuracy. Therefore, the transfer of the method required revalidation of the specificity of the quantitative signals ...
where 1/𝑇𝑏𝑢𝑙𝑘21/T2bulk represents the relaxation rate of the bulk-like liquid inside the pores, 𝜌ρ represents the relaxivity, a constant depending on the paramagnetic impurity content of the pore surface; wettability of the filling liquid; temperature; and the strength of the ...
In the 1H NMR spectrum of the unspiked FCHw-M2 sample, a group of signals was observed between δ 1.09 and 1.14, corresponding to an impurity. These signals were used as the internal reference, and their integral was normalized to a value of 100. Consequently, the integrals of the methyl...
The method of using residual solvent signal as an internal standard significantly simplifies sample preparation. 2.3. Main Types According to the physical state of the sample, qNMR techniques can be divided into liquid qNMR and solid qNMR, of which the most commonly used is liquid NMR. However,...