Analytical element containing photosensitive compound and filter layer and method of use

A multilayer analytical element for the determination of creatine kinase or an isoenzyme thereof comprising a nonporous transparent support having thereon three or more layers including a filter layer, and contained in at least one of said layers other than said filter layer, an interactive composition for creatine kinase, said composition comprising one or more reagents which cumulatively provide a detectable optical density change at a predetermined characteristic wavelength in response to action of creatine kinase on a substrate, one of said reagents being a photosensitive dye or dye precursor,

• said support having on one side:
• said filter layer containing at least one filter dye selected to absorb incident radiation other than radiation at said predetermined characteristic wavelength, produced in response to a reaction of creatine kinase or an isoenzyme thereof with its substrate and
• on the other side, in order, two or more layers including:
• a layer containing said photosensitive dye or dye precursor, and
• an outermost porous spreading layer.

A method for the determination of a clinically significant enzyme analyte comprising the steps of:

• A. contacting a sample of a liquid suspected of containing a clinically significant enzyme analyte with an analytical element comprising:
• a layer comprising an absorbent carrier material containing a substrate and an interactive composition for said analyte, said composition comprising a photosensitive compound which is capable of providing an optical density change at a predetermined characteristic wavelength in response to action of said analyte on said substrate, and
• a filter layer comprising at least one filter dye selected to absorb incident radiation other than radiation at said characteristic wavelength,
• to produce an optical density change detectable at said predetermined characteristic wavelength as a result of the presence of said enzyme in said sample, and
• B. determining said optical density change at said predetermined characteristic wavelength by directing incident radiation from transmission, reflection or fluorescent spectrophotometry to said element in such fashion that said incident radiation passes through said filter layer before it reaches said absorbent layer.

A method for the determination of total creatine kinase or an isoenzyme thereof comprising the steps of:

• A. contacting a sample of a liquid suspected of containing creatine kinase or an isoenzyme thereof with a multilayer analytical element comprising a nonporous transparent support having thereon three or more layers including a filter layer, and contained in at least one of said layers other than said filter layer, a substrate and an interactive composition for creatine kinase, said composition comprising one or more reagents which cumulatively provide a detectable optical density change at a predetermined characteristic wavelength in response to action of creatine kinase on said substrate, one of said reagents being a photosensitive dye or dye precursor,
• said support having on one side:
• said filter layer containing at least one filter dye selected to absorb incident radiation other than radiation at said predetermined characteristic wavelength, produced in response to a reaction of creatine kinase or an isoenzyme thereof with its substrate and
• on the other side, in order, two or more layers including:
• a layer containing said photosensitive dye or dye precursor, and
• an outermost porous spreading layer, to produce an optical density change detectable at said predetermined characteristic wavelength as a result of the presence of creatine kinase or an isoenzyme thereof in said sample, and
• B. determining said optical density change at said predetermined characteristic wavelength by directing incident radiation from transmission or reflection spectrophotometry to said element in such fashion that said incident radiation passes through said filter layer before it reaches said photosensitive dye or dye precursor layer.

A multilayer analytical element for the determination of creatine kinase or an isoenzyme thereof comprising a nonporous transparent support having thereon three or more layers including a filter layer, and contained in at least one of said layers other than said filter layer, an interactive composition for creatine kinase, said composition comprising one or more reagents which cumulatively provide a detectable optical density change at a predetermined characteristic wavelength in response to action of creation kinase on a substrate, one of said reagents being a photosensitive dye or dye precursor,

• said support having on one side, in order, three or more layers including:
• said filter layer containing at least one filter dye selected to absorb incident radiation other than radiation at said predetermined characteristic wavelength, produced in response to a reaction of creatine kinase or an isoenzyme thereof with its substrate and
• a layer containing said photosensitive dye or dye precursor, and
• an outermost porous spreading layer.

A multilayer analytical element for the determination of creatine kinase or an isoenzyme thereof comprising a nonporous support having thereon three or more layers including a filter layer, and contained in at least one of said layers other than said filter layer, an interactive composition for creatine kinase, said composition comprising one or more reagents which cumulatively provide a detectable optical density change at a predetermined characteristic wavelength in response to action of creatine kinase on a substrate, one of said reagents being a photosensitive dye or dye precursor,

• said support having on one side, in order, three or more layers including:
• a layer containing said photosensitive dye or dye precursor,
• said filter layer containing at least one filter dye selected to absorb incident radiation other than radiation at said predetermined characteristic wavelength, produced in response to a reaction of creatine kinase or an isoenzyme thereof with its substrate and
• an outermost porous spreading layer.