Scheme 1.
Schematic showing the HRP/H2O2 and nanoceria mediated oxidation of ampliflu. In the pH range 4–7, HRP/H2O2 oxidizes Ampliflu to a non-fluorescent final product (Resazurin). (a) In contrast, nanoceria oxidizes Ampliflu to the intermediate oxidation fluorescent product (Resorufin) at pH 7 (b), while at or below pH 5.0, nanoceria yields the terminal oxidized non-fluorescent product resazurin. (c). The ability of nanoceria to oxidize ampliflu to a stable fluorescent product in the pH range 6–8, will facilitate its use in ELISA. (d, e) without the use of H2O2.