Selective Colorimetric Detection of Hydrogen Sulfide Based on Primary Amine-Active Ester Cross-Linking of Gold Nanoparticles.

Hydrogen sulfide (H2S) is a highly toxic environmental pollutant and also an important gaseous transmitter. Therefore, selective detection of H2S is very important, and visual detection of it with the naked eye is preferred in practical applications. In this study, thiolated azido derivates and active esters functionalized gold nanoparticles (AE-AuNPs)-based nanosensors have been successfully prepared for H2S perception. The sensing principle consists of two steps: first, H2S reduces the azide group to a primary amine; second, a cross-linking reaction between the primary amine and active ester induces the aggregation of AuNPs. The AE-AuNPs-based nanosensors show high selectivity toward H2S over other anions and thiols due to the specific azide-H2S chemistry. Under optimal conditions, 0.2 μM H2S is detectable using a UV-vis spectrophotometer, and 4 μM H2S can be easily detected by the naked eye. In addition, the practical application of the designed nanosensors was evaluated with lake water samples.