Luminol-free chlorine chemiluminescence in an oil-in-water microemulsion medium

Abstract

A surfactantless oil-in-water microemulsion medium, water–n-hexane–2-propanol, was evaluated for the sensing of free chlorine based on luminol chemiluminescence under basic and unbuffered conditions. The results were compared with those in homogeneous and other microheterogeneous reaction media. Under unbuffered conditions, free chlorine provided strong light emission in the microemulsion medium, the signal being comparable with that in a 10^–2M NaOH aqueous solution. Transition metal ions (Fe²⁺, Cu²⁺, Co²⁺, Mn²⁺) gave rise to no light emission. Free chlorine in tap water was successfully determined with no interference from concomitant ions.