Abstract: A test device, test composition, and method are disclosed for determining the presence of a component in a sample. The device comprises a carrier matrix incorporated with a reactant system which produces a detectable response upon contact with the sample component. After a predetermined time interval elapses, the production of the detectable response is terminated by an inhibitor system also incorporated with the matrix. The test composition comprises the reactant and inhibitor systems. The method of use comprises contacting the test device with a test sample suspected of containing the component, permitting a predetermined time to elapse after contacting, and observing any detectable response produced.

Abstract: Devices and methods are provided for determining specific gravity or osmolality of liquids. The preferred devices comprise a carrier matrix incorporated with microcapsules having osmotically fragile, semipermeable polymeric membrane walls encapsulating therein a solute and a coloring substance. In use, the test device is contacted with the liquid to be tested, and color change on the carrier matrix is observed as a measure of the specific gravity or osmolality of the liquid.