Why Does Hemoglobin Cause Longer Fluorescence in Luminol Reactions?

[aspiring_1010]

Today in lab we performed two different chemiluminescent reactions - one involving the oxidation of luminol with H2O2 in a CuSO4 solution and the other the oxidation of luminol with H2O2 in a hemoglobin solution.

My question is, why would there be a difference in the duration of the fluorescence of luminol between CuSO4 and hemoglobin? Why would the hemoglobin solution fluoresce for longer?

 

[DrDu]

I would guess that CuSO4 is a better catalysator for the reaction than is Hemoglobine, but the quantum yield is higher with hemoglobine than with CuSO4.