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Chitosans with various degrees of deacetylation (D.D.), which were used as standard sample for FTIR determination, were prepared from completely deacetylated chitosan by homogeneous N-acetylation reaction. By combining four probable probe bands, i.e. 1655, 1560, 1380 and 1320 cm-1, eight probable reference bands, i.e. 3430, 2920, 2880, 1425, 1155, 1070, 1030 and 895 cm-1 and two baseline methods, the most suitable ratios Aprobe band/Aeterence band from IR spectra to determine the degree of acetylation of chitosan were evaluated from 48 combinations to be A1560/A2880, A1560/A2920 and A1655/A3430(A1560/A2880 is mostly recommended). The second baseline method, i.e. linking between adjacent two valleys, was better for measuring the absorbances of 1560 and 1655 cm-1 bands. The determination range of the D.D. (1%-100%) covered almost the whole range. The standard curves with A1560/A2880 and A1655/A3430 were also suitable for the determination of degree of substitution of other N-acylated chitosan, such as N-pr
By combining four probable probe bands, ie 1655, 1560, 1380 and 1320 cm- 1, eight probable reference bands, ie 3430, 2920, 2880, 1425, 1155, 1070, 1030 and 895 cm-1 and two baseline methods, the most suitable ratios Aprobe band / Aeterence band from IR spectra to determine the degree of acetylation of The second baseline method, ie linking between adjacent two valleys, was better for measuring the absorbances of 1560 and 1655 (A1560 / A2880 is mostly recommended) cm-1 bands. The determination range of the DD (1% -100%) covered almost the whole range. The standard curves with A1560 / A2880 and A1655 / A3430 were also suitable for the determination of degree of substitution of other N-acylated chi tosan, such as N-pr