METHOD OF QUANTITATIVE DETERMINATION OF CONCENTRATION OF POLYHEXAMETHYLENEGUANIDINE HYDROCHLORIDE IN WATER SOLUTION Russian patent published in 2015 - IPC G01N33/18 

FIELD: chemistry.

SUBSTANCE: invention relates to analytical chemistry, namely to method of determining concentration of polyhexamethyleneguanidine hydrochloride (PHMG) in water of different type. Method is based on interaction of PHMG cations with reagent representing preliminarily obtained colloidal solution of negatively charged silver particles in citrate buffer. In the course of determination aggregates of nanoparticles, Rayleigh scattering of which is measured by synchronous scanning of fluorescence spectrum with zero difference of emission and registration wavelengths, are formed; signal is measured at 485 nm. In tap water linearity of calibration curve is observed in the range 0.07-2.2 mg/l, in sewage water of stormwater drain - in the range 0.007-0.7 and 0.7-2.2 mg/l, relative standard deviation constitutes 0.02-0.03. Determination of PHMG (4·10^-7 M PHMG in pure water) is not prevented by presence of admixtures in quantity not higher than: 0.05 M of NaCl, 200 mg/l of calcium ions, 120 mg/l of magnesium ions, 0.5 mg/l of copper (II) ions, 0.14 mg/l of sodium n-dodecylsulphate, 0.1 mg/l of humic acids, 0.25 mg/l of non-ionic surfactants, 0.025 mg/l of cationic surfactants, 0.1 mg/l of bovine serum albumin, 2.5 mg/l of polyethyleneimine.

EFFECT: application of method makes it possible to extend range of determinable PHMG concentrations in water, in particular determine PHMG concentrations in sewage water at the level of MPC for water of fishery purposes (0,01 mg/l) and lower.

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