The Oxidation of Luminol an Experiment to Maximize the Efficiency of Chemiluminescence from Luminol

Abstract

In this work, seven inorganic salts, KCl, Na₂SO₄, MgSO₄-7H₂O, ZnCl₂, Na₂CrO₄, CuSO₄-5H₂O, and K₃[Fe(CN)₆], were used as catalysts to induce chemiluminescent luminol oxidation in alkaline aqueous media. It was observed that simple salts containing either Mg²⁺, Zn²⁺, Na⁺ and K⁺ cations or SO₄²⁻ and Cl⁻ anions, are not active as catalysts. On the other hand, the relative order of activity detected for the active chemiluminescent salts containing Fe(III), Cu(II) and Cr(VI) cations is K₃[Fe(CN)₆] < CuSO₄-5H₂O < Na₂CrO₄. The intensity of the emitted light agrees with the standard reduction potentials of the corresponding redox couple and with the presence of paramagnetic species in the aqueous solutions. The inhibition effect of mannitol was also studied.