Förster-free Effect Fluorescence Quenching of 5,10,15,20-tetraphenylporphyrin in Solution

Abstract

Inner-lter absorption of the exciting light by the quencher or may be cause of large errors in the evaluation of quenching e ciencies in measurements of uorescence quenching. We performed uorescence measurements of 5,10,15,20-tetraphenylporphyrin toluene solution in a wide concentration range. We have shown a Förster-free uorescence quenching in a right-angle geometry experiment, caused by second order inner lter. We proposed to perform measurements in a front-surface geometry to investigate the nature of quenching not related to the inner lters. We have shown that concentration effects in tetraphenylporphyrin solutions in toluene are not accompanied by a decrease in the uorescence intensity in a front-surface geometry at concentrations of 10 − 3 -10 − 7 mol/l. It was possible to separate the phenomena of the internal lters from the processes occurring in a liquid medium. Our results are of great importance due to the widespread fundamental research of porphyrin-based dyes properties. HighlightsThe Förster-free effect uorescence is observed up to closed to the ultimate solubility concentrations in tetraphenylporphyrins toluene solution at concentrations of 10 -3 -10 -7 mol/l.Förster radius was estimated for 5,10,15,20-tetraphenylporphyrin molecules.Concentration quenching of tetraphenylporphyrin solutions was studied in a wide range of concentrations A correction experimental method is proposed conditions to minimize inner lter effects