Analytical Sciences

Determination of Biguanide Groups in Polyhexamethylene Biguanide Hydrochloride by Titrimetric Methods

Toshiaki HATTORI,  Yasuko NAKATA, and Ryo KATO

Research Center for Chemometrics, Toyohashi University of Technology, Tempaku Hibarigaoka 1-1, Toyohashi 441-8580, Japan

The biguanide concentration of polyhexamethylene biguanide hydrochloride (PHMB-HCl) was measured by non-aqueous titration with HClO₄, argentometric titration, the Kjeldhal method, and colloidal titration. The summation value of nonaqueous titration and argentometric titration corresponded to two titrable nitrogens in five nitrogens per one unit of PHMB-HCl, and consisted with the result of the Kjeldhal method to the five nitrogens. The colloidal titration of PHMBHCl at pH 2.05 was equal to that with the two nitrogens. The relative standard deviations of non-aqueous titration, argentometric titration, the Kjeldhal method, and colloidal titration were 0.50% for 8 runs, 0.13% for 7 runs, 3.61% for 6 runs, and 0.69% for 6 runs, respectively.

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