Implementation of laser induced fluorescence in a pulse radiolysis experiment – a new way to analyze resazurin-like reduction mechanisms

Abstract : Resazurin (RNO) reduction by hydrated electrons produces a fluorescent molecule: resorufin (RN). To take advantage of RN fluorescence, a novel setup is designed by implementing fluorescence detection induced by laser in a pulse radiolysis experiment. Time resolved fluorescence spectra were recorded with a fast gated intensified CCD camera during the reduction of RNO from μs to ms. Two 532 nm laser types have been used to describe the short μs range by a 5 ns Q-switch laser and the μs–ms range by a CW DPSS laser. By fitting the simulated model to the experimental data a second order rate constant of 109 M−1 s−1 was re-evaluated. This method should be considered in the near future in many in situ and real time measurements for evaluating radical production.