The commercially available fluorescence dye 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) can be used as a selective molecular probe for the detection of caffeine in aqueous solution.

A novel procedure for the evaluation of total reactive antioxidant potentials (TRAP) is described. The method is based on the measurement of the bleaching of pyranine by peroxyl radicals. The addition of the antioxidants produces a clear induction time whose magnitude is directly related to the antioxidant concentration. A comparison of the values obtained with those reported employing closely ...

The short and intermediate time scale dynamics of the photoacid pyranine (1-hydroxy-3,6,8-pyrenetrisulfonic acid, commonly referred to as HPTS) are studied with visible pump-probe spectroscopy in various solvents to elucidate the nature of its proton-transfer kinetics in water. The observed time dependences of HPTS are compared with those of the methoxy derivative, MPTS. A global fitting proced...