K-Blue Aqueous is a revolutionary 100% solvent-free, non-volatile TMB substrate. It contains 3,3,5,5 tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) in a one-bottle format with long-term stability and high activity. K-Blue Aqueous develops a deep blue color in the presence of peroxidase labelled conjugate and is ideal for end users working under strict regulatory requirements. The formula is compliant with Annex XVII for REACH and contains no hazardous substances at or above published reporting levels. K-Blue Aqueous has been optimized for use with microwell applications, especially ELISA. This substrate is not applicable for use with assays requiring a precipitating substrate. Stable for a minimum of 36-months when stored at 2-8C.