Oxygen Sensing Based on the Room Temperature Phosphorescence Intensity Quenching of Some Lead–8-hydroxyquinoline Complexes

Abstract

8-Hydroxy-5-quinolinesulfonic acid and 8-hydroxy-7-quinolinesulfonic acid chelates of lead, when retained on the surface of anion-exchange resin beads, exhibit strong room temperature phosphorescence (RTP) in suspensions of both aqueous and organic solutions. Two oxygen transducers based on RTP quenching measurement of the Pb chelates were evaluated. The immobilised RTP chelates proved to be photochemically stable and their RTP emission highly sensitive towards oxygen. Detection limits lower than 0.1% v/v of oxygen in argon were found. Typical response times were <2 s for a full signal change for gaseous mixtures and about 90 s for solution samples and organic solvents. The sensors were successfully tested for the determination of dissolved oxygen in tap waters.