FeIII–TAML activator: A potent peroxidase mimic for chemiluminescent determination of hydrogen peroxide

Efforts to replace native peroxidase with its low molecular weight alternatives have stimulated a search for peroxidase mimetics. Herein we describe the oxidation of luminol with hydrogen peroxide catalyzed by commercially available FeIII–TAML activator 1a, which was shown to be a more active catalyst than hemin. At FeIII–TAML activator 1a use in chemiluminescent assay for H2O2 determination the detection limit value (3σ) of 5×10−8 M was similar to the detection limit obtained with horseradish peroxidase (1×10−7 M) and significantly lower than that obtained in the presence of hemin (6×10−7 M). The linear ranges (R2=0.98) of the assay were 6×10−8–1×10−6 M and 6×10−7–1×10−6 M H2O2 for FeIII–TAML 1a and hemin, respectively. The CV values for FeIII–TAML 1a-based assay measured within the working range varied from 1.0% to 3.7% (n=4), whereas in the case of hemin −5.0% to 9.7% (n=4). Moreover, the sensitivity of FeIII–TAML 1a-based method was 56 and 5 times higher than that of hemin- and HRP-based methods, respectively. The obtained results open good perspectives to apply FeIII–TAML activator 1a in CL analytical methods instead of hemin, a traditionally used peroxidase mimetic.