Absorbance change and static quenching of fluorescence of meso-tetra(4-sulfonatophenyl)porphyrin (TPPS) by trinitrotoluene (TNT)

Meso-tetra(4-sulfonatophenyl)porphyrin (TPPS) interacts with trinitrotoluene (TNT) and forms a 1:1 complex with a new absorbance peak at 422 nm. TNT quenches TPPS emission intensity at 645 and 702 nm when excited at 413 nm. The TPPS–TNT complex is formed in the ground state on the basis of a linear Stern–Volmer plot indicative of static quenching. The association constants determined from absorbance and fluorescence studies are in excellent agreement.