Size tunable copper nanocluster aggregates and their application in hydrogen sulfide sensing on paper based devices
Polystyrene sulfonate (PSS) a strong polyelectrolyte, was used to prepare red photoluminescent PSS penicillamine (PA) copper (Cu) nanoclusters (NC) aggregates, which displayed high selectivity and sensitivity to the detection of hydrogen sulfide (H2S) The size of the PSS PA Cu NC aggregates could be readily controlled from 5.5 mm to 173 nm using different concentrations of PSS, which enabled better dispersity and higher sensitivity towards H2S. PSS PA Cu NC aggregates provided rapid H2S detection by using the strong Cu S interaction to quench NC photoluminescence as a sensing mechanism. As a result, a detection limit of 650 nM, which is lower than the maximum level permitted in drinking water by the World Health Organization, was achieved for the analysis of H2S in spring water samples. Moreover, highly dispersed PSS PA Cu NC aggregates could be incorporated into a plate format paper based analytical device which enables ultra low sample volumes (5 mL) and feature shorter analysis times (30 min) compared to conventional solution based methods. The advantages of low reagent consumption, rapid result readout, limited equipment, and long term storage make this platform sensitive and simple enough to use without specialized training in resource constrained settings.
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