摘要 |
<p>An element for the analysis of liquids contains a radiation-transmissive, detectable species migration-inhibiting layer interposed between a porous radiation-blocking layer and a radiation-transmissive reagent layer. All three layers are permeable to a predetermined analyte. The reagent layer contains a composition that provides a detectable species such as a dye in proportion to the concentration of the analyte that diffuses into the reagent layer from the overlying porous radiation-blocking layer. The detectable species migrationinhibiting layer acts to reduce the migration of, for example, dye from the reagent layer into the porous radiation-blocking layer, where the optical density of the dye cannot easily be measured. Optionally, the above-described three layers can be carried on a radiation-transmissive support, and other layers such as spreading layers, registration layers, and subbing layers can also be present in the element.</p> |