Patent ID: 7022285
Filing Date: 2006-04-04
Classification: G01N,Y10T

Abstract:
1. In an integral multilayer analytical element for the determination of ammonia or an ammonia-producing substance comprising a transparent support, an indicator layer containing an indicator which produces a detectable change by gaseous ammonia, a liquid blocking layer permitting gaseous ammonia to pass therethrough, a reagent layer containing an alkaline buffering agent and optionally a reagent capable of reacting with said ammonia-producing substance to produce ammonia, and a spreading layer, adhesively laminated in this order, the improvement which comprises that said liquid blocking layer is composed of at least two types of porous membrane layers which are impermeable to aqueous liquids, wherein a pore diameter of an uppermost porous membrane of said at least two types of porous membrane layers, which contacts said reagent layer, is smaller than that of a just underlying porous membrane.