Copper (Ii) ion‐modified gold nanoclusters as peroxidase mimetics for the colorimetric detection of pyrophosphate

Abstract

Copper (II) ions have been shown to greatly improve the chemical stability and peroxidase‐like activity of gold nanoclusters (AuNCs). Since the affinity between Cu2+ and pyrophosphate (PPi) is higher than that between Cu2+ and AuNCs, the catalytic activity of AuNCs‐Cu2+ decreases with the introduction of PPi. Based on this principle, a new colorimetric detection method of PPi with high sensitivity and selectivity was developed by using AuNCs‐Cu2+ as a probe. Under optimized conditions, the detection limit of PPi was 0.49 nM with a linear range of 0.51 to 30,000 nM. The sensitivity of the method was three orders of magnitude higher than that of a fluorescence method using AuNCs‐Cu2+ as the probe. Finally, the AuNCs‐Cu2+ system was successfully applied to directly determine the concentration of PPi in human urine samples.