SENSOR OF CONCENTRATION OF AMMONIA Russian patent published in 2001 - IPC

FIELD: analytical instrumentation, ecological monitoring systems. SUBSTANCE: sensor of concentration of ammonia includes substrate 1 carrying electrodes 2, 3 and sensitive layer 4 based on polyaniline containing modifying additive. Modified film of polyaniline is continuously kept in fixed oxidation-reduction condition by way of action on it with D C voltage having value 35.0 mV±10.0 mV. In the capacity of modifying additive there are used: heteropolyacids of series 1:12 of common formula H_3+nAW_12-nMe_nO₄₀(A = P,Si,As; Me = Mo,V;, where n=0-12, or their potassium, sodium, lithium, ammonium, cerium, cobalt, manganese salts, unsaturated analogs of heteropolyacids of series 1:12 created by way of removal of one out of three atoms in molecule of common formula H_3+nAW_12-n-xMe_nO_40-2x ( A= P, Si, As, Me=Mo, V; n=0-12 ) or their potassium, sodium, lithium, ammonium, cerium, cobalt, manganese salts; heteropolyacids of series 2:18 of common formula H_6+nA₂W_18-nMe_nO₆₂ ( A= P, Si, As, Me=Mo, V; n=0-18 ) or their potassium, sodium, lithium, ammonium, cerium, cobalt, manganese salts; unsaturated analog of heteropolyacids of series 2:18 formed by removal of one to six atoms out of molecules of metal of common formula H_3+nAW_12-nMe_nO₄₀ ( A= P, Si, As, Me= Mo, V; N= 0-18) or their potassium, sodium, lithium, ammonium, cerium, cobalt, manganese salt; copper, cobalt, nickel chloride; cobalt H_6+nA₂W_18-n-xMe_nO_62-2x. EFFECT: increased sensitivity and selectivity of sensor to ammonia in its mixture with other gases. 6 cl, 3 dwg, 3 tbl