Electrochemiluminescence behavior of meso -tetra(4-sulfonatophenyl)porphyrin in aqueous medium: its application for highly selective sensing of nanomolar Cu 2+

Abstract

The cathodic electrochemiluminescence (ECL) behavior of meso-tetra(4-sulfonatophenyl)porphyrin (TSPP) with potassium peroxydisulfate (K₂S₂O₈) as the coreactant in aqueous solution with strong and stable emission was exploited to determine Cu²⁺ down to nanomolar concentration. Two possible reaction mechanisms have been proposed to understand the generation of ECL by the TSPP/K₂S₂O₈ system. The effects of the concentration of TSPP and K₂S₂O₈, pH of the medium, and scan rate on the ECL intensity were studied in detail. The ECL intensity was efficiently quenched by trace amounts of Cu²⁺. This phenomenon was used to develop a new method, which can offer rapid, reliable, and selective detection of Cu²⁺. Under the optimum conditions, plots of the ECL of the TSPP/K₂S₂O₈ system versus the concentration of Cu²⁺ are linear in the range of 5 to 160 nM with a detection limit of 1.56 nM (S/N = 3). The proposed ECL sensor was successfully applied for analysis of tap and river water samples. It is anticipated that TSPP could be a new class of promising luminescent agent for ECL sensors.

Graphical Abstract

A two-step cathodic elelctrochemiluminescence (ECL) behavior of TSPP/K₂S₂O₈ system in the aqueous solution and Cu²⁺ determination using the same

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