A method of detecting an enzymatic activity, comprising: providing a sample that may comprise a source of one or more predetermined enzymatic activities; a first indicator system comprising a first indicator reagent with a first absorbance spectrum, wherein the first indicator reagent comprises a pH indicator dye or a redox dye, wherein the first indicator reagent can be converted by a first predetermined enzymatic activity to a first biological derivative; a second indicator system comprising a second indicator reagent that is converted by the first predetermined enzymatic activity to a second biological derivative with a second emission spectrum, wherein the second indicator reagent comprises a fluorogenic enzyme substrate; a substrate that receives and concentrates the first indicator reagent from an aqueous mixture; wherein the substrate comprises charged nylon; and an instrument that detects the first indicator reagent or the second biological derivative, wherein the instrument comprises an optical path; forming a first aqueous mixture comprising the sample, the first indicator reagent, and the second indicator reagent; bringing the first aqueous mixture into fluid communication with the substrate to form a second aqueous mixture in which a concentration of the first indicator reagent is lower than the concentration of the first indicator reagent in the first aqueous mixture; observing the substrate to detect the first indicator reagent or the first biological derivative; and detecting a presence or absence of fluorescence from the second biological derivative, wherein detecting a presence or absence of fluorescence from the second biological derivative comprises using the instrument to detect the second biological derivative, wherein the optical path does not intersect any portion of the substrate; wherein the first absorbance spectrum includes detectable absorbance in at least a portion of wavelengths present in the second emission spectrum; wherein detecting the presence or absence of fluorescence from the second biological derivative comprises detecting the presence or absence of fluorescence in the second aqueous mixture. providing a sample that may comprise a source of one or more predetermined enzymatic activities; a first indicator system comprising a first indicator reagent with a first absorbance spectrum, wherein the first indicator reagent comprises a pH indicator dye or a redox dye, wherein the first indicator reagent can be converted by a first predetermined enzymatic activity to a first biological derivative; a second indicator system comprising a second indicator reagent that is converted by the first predetermined enzymatic activity to a second biological derivative with a second emission spectrum, wherein the second indicator reagent comprises a fluorogenic enzyme substrate; a substrate that receives and concentrates the first indicator reagent from an aqueous mixture; wherein the substrate comprises charged nylon; and an instrument that detects the first indicator reagent or the second biological derivative, wherein the instrument comprises an optical path; a sample that may comprise a source of one or more predetermined enzymatic activities; a first indicator system comprising a first indicator reagent with a first absorbance spectrum, wherein the first indicator reagent comprises a pH indicator dye or a redox dye, wherein the first indicator reagent can be converted by a first predetermined enzymatic activity to a first biological derivative; a second indicator system comprising a second indicator reagent that is converted by the first predetermined enzymatic activity to a second biological derivative with a second emission spectrum, wherein the second indicator reagent comprises a fluorogenic enzyme substrate; a substrate that receives and concentrates the first indicator reagent from an aqueous mixture; wherein the substrate comprises charged nylon; and an instrument that detects the first indicator reagent or the second biological derivative, wherein the instrument comprises an optical path; forming a first aqueous mixture comprising the sample, the first indicator reagent, and the second indicator reagent; bringing the first aqueous mixture into fluid communication with the substrate to form a second aqueous mixture in which a concentration of the first indicator reagent is lower than the concentration of the first indicator reagent in the first aqueous mixture; observing the substrate to detect the first indicator reagent or the first biological derivative; and detecting a presence or absence of fluorescence from the second biological derivative, wherein detecting a presence or absence of fluorescence from the second biological derivative comprises using the instrument to detect the second biological derivative, wherein the optical path does not intersect any portion of the substrate; wherein the first absorbance spectrum includes detectable absorbance in at least a portion of wavelengths present in the second emission spectrum; wherein detecting the presence or absence of fluorescence from the second biological derivative comprises detecting the presence or absence of fluorescence in the second aqueous mixture.