Figure 7.

The rate of oxidation of 2'7'-dichlorodihydrofluorescein by copper is slowed by AAOS. DCFH₂ (200 μL of 90 μM in 20 mM carbonate buffer, pH 7.0) and 80 μL of mineral solution (100 μM in 20 mM carbonate, pH 7.0) were mixed in a standard UV-Vis cuvette; total volume 300 μL. The reaction was initiated by addition of 20 μL of 0.3% H₂O₂ yielding a final concentration of 88 mM. The formation of DCF was followed by its absorbance at 500 nm.