Electrochemiluminescence of Tris(8-hydroxyquinoline-5-sulfonic acid)aluminum(III) in Aqueous Solution
The electrochemiluminescence (ECL) of tris(8-hydroxyquinoline-5-sulfonic acid)aluminum(III) in aqueous solution is reported. ECL is generated by complexing aluminum ions with the chelating agent 8-hydroxyquinoline-5-sulfonic acid (HQS) to form Al(HQS)3, followed by oxidation in the presence of tri-n-propylamine (TPrA). The ECL intensity peaks a potential corresponding to oxidation of both TPrA and Al(HQS)3, and the ECL emission spectrum (λmax = 499 nm) matches the photoluminescence emission spectrum, indicating that the emission is from a Al(HQS)3* excited state. ECL efficiencies (φecl, photons generated per redox event) of 0.002 using Ru(bpy)32+ (φecl = 1) as relative standard. Conditions for ECL emission were optimized and used to generate a calibration curve that was linear over the 7 × 10-6−4 × 10-4 M (5−281 mg/L (ppm)) range with a theoretical limit of detection of 1 ppm. The ECL of several metal ions other than aluminum with HQS and effects on Al(HQS)3 ECL were also examined.
photoluminescence, solution chemistry, metals, aluminum, ions
Muegge, Brian D., Sean Brooks, and Mark M. Richter. "Electrochemiluminescence of tris (8-hydroxyquinoline-5-sulfonic acid) aluminum (III) in aqueous solution." Analytical chemistry 75, no. 5 (2003): 1102-1105.