A new approach to the spectrophotometric determination of polyhexamethyleneguanidinium chloride.

It has been demonstrated that the reaction of Phenol Red ( PR) with polyhexamethyleneguanidinium chloride ( PHMG) gives an ion associate and several aggregates. The composition of the latter ones was determined by spectrophotometry, turbidimetry, refractometry, and conductometry. The introduction of PHMG into PR solutions PR leads to the redistribution of the intensity of absorption bands and the appearance of extreme points corresponding to the regions of the maximal accumulation of the formed aggregates with the following stoichiometry: c: c = 8 (12, 16, 27, 54) : 1. A procedure has been developed for determining PHMG in disinfecting agent 'Biopag-D' employing the extreme points. The procedure provides PHMG the determination of PHMG with an error of 1%. [ABSTRACT FROM AUTHOR]