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Improved method for i.r. determination of the degree of N-acetylation of chitosan

1992; Elsevier BV; Volume: 14; Issue: 3 Linguagem: Inglês

10.1016/s0141-8130(05)80007-8

1879-0003

Alasdair Baxter, Michael Dillon, K.D. Anthony Taylor, George A. F. Roberts,

Electrochemical sensors and biosensors

Three published i.r. absorption band ratios for determining the % N-acetylation of chitosan have been used to follow the rate of alkaline deacetylation of chitin. Only one, the A1655/A3450 ratio, gives the expected rate of deacetylation curve. Consideration of the various i.r. ratios has led to a new relationship, % N-acetylation = (A1655/A3450) × 115, where the absorbance of the amide I band at approximately 1655 cm−1 is determined using the baseline proposed previously. The values obtained using this proposed relationship agree closely with those obtained from dye adsorption measurements for chitosans having % N-acetylation values in the range 0–55%.