Control of pH for separated quantitation of nitrite and cyanide ions using photoluminescent copper nanoclusters

摘要

A dual sensing probe has been developed for the detection of nitrite (NO2-) and cyanide (CN-) ions based on the analyte-induced photoluminescence (PL) quenching of thiosalicylic acid (TA) capped-copper (Cu) nanocluster (NC) aggregates. The TA-Cu NC aggregates prepared from Cu2+ and TA emit at 420 nm when excited at 338 nm, with a quantum yield of 13.2%. The PL quenching of the TA-Cu NC aggregates by NO2-is through a redox reaction between HNO2 and TA under acidic conditions, while that by CN- ions in a basic solution is through an etching process. By controlling pH values at 5.0 and then at 8.0, the probe allows consecutive quantitation of NO2-and CN-ions in water samples, with limits of detection of 5 mM and 5 nM, respectively, at a signal-to-noise ratio of 3. The practicality of this probe has been validated through the determination of the concentrations of NO2-and CN-ions in representative lake water samples.