REAGENT INDICATOR PAPER TESTS BASED ON CHROMOGENIC CELLULOSES AND METHOD OF THEIR PREPARATION Russian patent published in 1998 - IPC

FIELD: analytical methods. SUBSTANCE: invention may be used for rapidly determining allowable and dangerous concentrations of organic and inorganic substances in drinking water, surface waters, waste waters, soil, foods, and also pathologic concentrations of substances in body fluids. Tests are made in the form of primary measuring converters: 8-16-mm sheets and 8-45-mm disks with specific weight 60-240 g/sq.m based on chromogenic celluloses prepared by consecutive treatment of epoxidated cellulose with active reagents. Primary active reagents are benzidines with general formula (1), where R₁-R₄ are hydrogen or methyl; or R₁ and R₂ are hydrogen and R₃ and R₄ are methyl or methoxy. EFFECT: increased sensitivity. 2 cl, 3 dwg, 3 ex