Determination of the degree of deacetylation of chitosan by potentiometric titration preceded by enzymatic pretreatment

A novel method for determining the degree of deacetylation of chitosan is described. This involves two-abrupt-change potentiometric titration preceded by enzymatic pretreatment (EP-TPT) with chitosanolytic enzyme (cellulase) to reduce the viscosity of chitosan solution. Acidic titration is preferred for the rapid response within the two abrupt changes of pH. Half-deacetylated chitosan (almost soluble in all pH range) was used to prove that the enzyme did not interfere with the measurement. Compared with other methods such as 1H NMR, XRD, FT-IR and linear potentiometric titration, the proposed method is simple, low-cost, accurate, reliable and easy to operate for industrial application.