Abstract: Systems are provided for the detection of hydrogen peroxide for determination of analytes, where a N-alkylated 3-oxyaniline derivative is covalently bonded to a bibulous support and the other component for forming an indamine dye may be non-covalently bound to the support. Upon passage of a transport medium across the support in the presence of hydrogen peroxide and a peroxidase, an indamine dye is formed. Where a limited amount of hydrogen peroxide is introduced at a site proximal to one end of the support, and the hydrogen peroxide migrates toward the other end, the distance of color development will be related to the amount of hydrogen peroxide, which can be correlated to the amount of analyte in a sample.