DETERMINATION OF DEGREE OF DEACETYLATION OF CHITOSAN BY H-1-NMR SPECTROSCOPY
DETERMINATION OF DEGREE OF DEACETYLATION OF CHITOSAN BY H-1-NMR SPECTROSCOPY
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DOI：
10.1007/bf00299352
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发表时间：
1991-07-01
期刊：
影响因子：
3.2
通讯作者：
NAKAJIMA, A
中科院分区：
文献类型：
--
作者：
HIRAI, A;ODANI, H;NAKAJIMA, A
介绍了一种用核磁共振氢谱测定壳聚糖脱乙酰度的新方法。以2wt%Cd_3COOD/D_2O和2wt%DC_1/D_2O为壳聚糖的溶剂，在70℃下进行了测定。在DC1/D2O体系中，应考虑壳聚糖的水解度，45度脉冲所需的脉冲重复延迟为40s。而对于Cd_3COOD/D_2O体系，由于Cd_3COOD中的Cd_2H残基与N-乙酰残基中的CH_3残基的信号重叠，需要测定两个谱线的差值，因此对于Cd_3COOD/D_2O体系，6s的脉冲重复延迟对于45度的脉冲来说是足够的，并且需要高磁场的核磁共振装置。与传统的胶体滴定和元素分析方法相比，该方法更加有效、准确和简便。并对壳聚糖的H-1和C-13核磁共振谱进行了归属。
This paper describes a novel method to determine the degree of deacetylation of chitosan by H-1 NMR spectroscopy. Measurements were carried out at 70-degrees-C by using 2 wt% CD3COOD/D2O and 2wt% DC1/D2O as solvents for chitosan. In the case of DC1/D2O system, effect on hydrolysis of chitosan should be taken into consideration, and the pulse repetition delay required for 45-degrees pulse is 40s. Whereas, in regard to CD3COOD/D2O system, 6s pulse repetition delay is enough for 45-degrees pulse, and moreover, high magnetic field NMR apparatus is necessary, because signal of CD2H residue in CD3COOD overlaps with that of CH3 residue in N-acetyl residue and determination of the difference of two spectra is required. The proposed method is more effective, precise and simple, comparing with the conventional colloid titration and elemental analysis methods. Assignments of H-1 and C-13 NMR spectra of chitosan are also reported.