Use of micellar solutions to improve the fluorescence determination of 2-naphthol

Abstract

The effect of ionic and non-ionic surfactants on the fluorescence of 2-naphthol was studied in connection with its acid-base properties and proton-transfer reactions during the lifetime of the excited state. It is shown that sodium dodecyl sulphate (SDS) and polyoxyethylene-23 lauryl ether (Brij 35) inhibit proton-transfer and proton-induced quenching reactions. As a result, the fluorescence spectrum exhibits, on either side of the ground-state pK, only one band corresponding to the species that is actually present in the test solution. An account is given of the practical application of the surfactant effect.