EFFECT OF TEMPERATURE AND pH ON THE QUENCHING OF TRIPLET LUMIFLAVIN IN THE PRESENCE AND ABSENCE OF FERRI‐ AND FERROCYANIDE

Abstract

Abstract— –Flash photolysis at 450 nm over the temperature range 0.8–60°C was used to determine Arrhenius parameters for the first and second order disappearance of triplet lumiflavin (1.66 µ.M) at a flash energy of 2 kj in deaerated phosphate buffer at varying pH: 3Lf → Lf0 3Lf +3Lf → Lf0+ Lf0 Arrhenius parameters were also determined for the pseudo first‐order quenching of triplet lumiflavin by 10 µM ferri‐ and ferrocyanide ions, 3Lf + Fe3+→ Fe3+→ Lf0+ Fe3+ (energy transfer) 3Lf + Fe2+→ Lf‐+ Fe3+ (electron transfer) and for disappearance of the semireduced lumiflavin in the presence of ferrocyanide at pH 6.8, by the second‐order reaction Lf‐+Lf ‐→ Lf0+ Lf=.