RANDOMLY SEGMENTED THERMOPLASTIC POLYURETHANES AS MATRIX FOR ELECTROCHEMICAL ANALYSIS OF Ca++ IONS

摘要

Composition, comprising in homogeneous distribution A) at least one salt containing a lipophilic anion, B) a plasticiser-free thermoplastic randomly segmented polyurethane which is soluble in organic solvents, a polyurea or a polyurethane urea, which components are formed from a) 5-45 % by weight of an aromatic, cycloaliphatic or linear aliphatic diisocyanate, b) 0-20 % by weight of a linear or branched C2-C12alkylenediol or C2-C12alkylenediamine, c) 0-75 % by weight of a polytetrahydrofuran or aminopropyl-terminated polytetrahydrofuran, d) 0-10 % by weight of a polyethylene glycol or aminopropyl-terminated polyethylene glycol, e) 0-75 % by weight of a polypropylene glycol or aminopropyl-terminated polypropylene glycol, which composition contains f) 15-95 % by weight of a hydroxy-, hydroxypropyl- or aminopropyl-terminated polydimethylsiloxane, the percentages relating to the amount of polymer, and the sum of components a) to f) being 100, and C) a nonionic ionophore which forms a complex with Ca++ ions. The invention also relates to an electrode for calcium analysis, containing said composition in the form of a membrane, to a process for the electrochemical analysis of Ca++ ions in solution as well as to the use of this composition for the electrochemical analysis of Ca++ ions.