Compositions and elements containing triarylmethane leuco dyes and methods using same

A dry analytical element for the determination of an analyte in an aqueous liquid, said element comprising:

• a support having thereon a porous spreading zone and
• (1) an interactive composition which produces hydrogen peroxide upon interaction with said analyte, (2) a substance having peroxidative activity and (3) a triarylmethane leuco dye which provides a dye having a maximum absorption at a wavelength equal to or greater than about 600 nm upon interaction with hydrogen peroxide, said leuco dye having the structure:
• ##STR40## wherein R is a 5- to 15-membered aromatic heterocyclic moiety provided that said moiety does not have an --NH-- group in the ring;
• and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently alkyl, alkaryl, aralkyl, aryl or a heterocyclic moiety, or R.sup.1 and R.sup.2 or R.sup.3 and R.sup.4 independently taken together with the respective nitrogen atom reperesent the atoms necessary to complete a heterocyclic ring.

A method for determing hydrogen peroxide or an analyte which reacts to produce hydrogen peroxide in an aqueous liquid, said method comprising the steps of:

• A. physically contacting a sample of said liquid with a composition comprising a substance having peroxidative activity and tariarylmethane leuco dye which provides a dye having a maximum absorption at a wavelength equal to or greater than about 600 nm upon interaction with hydrogen peroxide, said leuco dye having the sructure:
• ##STR42## wherein R is a 5- to 15-membered aromatic heterocyclic moiety provided that said moiety does not have an --NH-- group in the ring;
• and R' and R" are independently open chain or cyclic amines;
• and
• B. detecting said dye at a wavelength equal to or greater than about 600 nm.