Patent ID: 8735083

Claim:
A method for inhibiting peroxidase enzymatic activity in an aqueous solution comprising the steps of: providing an aqueous solution comprising a peroxidase enzyme, an electron acceptor substrate, and ABTS (2,2′-azino-di-(3-ethylbenzothiazoline-6-sulphonic acid) as an electron donor substrate, wherein the peroxidase enzyme catalyzes turnover of ABTS to yield a colored oxidized product of ABTS which can be measured spectrophotometrically, and adding an acidic stop reagent to the solution wherein the stop reagent comprises sodium dodecyl sulfate (SDS) and whereby the pH of the solution is adjusted to between about 2.5 and 4.2, and further whereby SDS is present in the solution at a concentration of between 0.25% and 2.5% weight by volume, thereby inhibiting the peroxidase enzymatic activity while stabilizing the oxidized product to avoid precipitation of the substrate and maintain the spectrophotometric measurement of the solution.