After incubating the reaction at room temperature for at least 20 minutes, measure the absorbance at 595 nm on a plate reader (Spectramax M2).
Calculate the concentration of hydrogen peroxide by reference to a standard curve (100uM, 33.3uM, 11.1 uM, 3.7 uM and 0.0 uM H2O2) made in the corresponding media.
NB: Dilute culture supernatants as appropriate to bring measurements into the assay’s linear range.
An example of a typical standard curve generated by the assay. Error bars (1SD, n=3) are too small to be seen.