Abstract: A multilayer analytical element has been prepared for accurate and rapid colorimetric determination of ethanol in aqueous specimens using alcohol dehydrogenase and an oxidized nicotinamide coenzyme. The element includes at least one reagent layer beneath a porous spreading layer. This reagent layer has a crosslinked polymeric binder prepared, in part, with a polymerizable monomer having a halomethylcarbonyl, haloethylcarbonyl, halomethylsulfonyl or haloethylsulfonyl group. Alcohol dehydrogenase is in a layer of the element for reaction with the analyte.

Abstract: A colorimetric assay for the determination of conjugated or unconjugated bilirubin in biological fluids can be carried out with an improved analytical element. The element includes a support having thereon a gelatin-free mordant layer with a positively-charged interactive mordant having at least one binding site for bilirubin, a radiation-blocking layer, and a porous spreading layer. The interactive mordant is dispersed in a binder material of crosslinkable copolymers which include a monomer capable of reaction with a crosslinking agent to crosslink the copolymer.

Abstract: A dry analytical element for the determination of serum cholinesterase (CHE) activity is disclosed. The element analyses undiluted body fluids and employs butyrylthiocholine as the substrate for CHE. Butyrylthiocholine is hydrolyzed by serum cholinesterase and liberates butyric acid and thiocholine. The thiocholine liberated then reduces ferricyanide to ferrocyanide and the rate of change is measured by reflectance densitometry.