Water-dispersed fluorescent silicon nanodots as probes for fluorometric determination of picric acid via energy transfer.

Abstract

Water-dispersed fluorescent silicon nanodots (SiNDs) were synthesized by a one-pot hydrothermal method starting from tetraethyl orthosilicate (TEOS) as silicon source and trisodium citrate as reducing reagent. The method is simple and convenient. The SiNDs, with excitation/emission peaks at 347/440nm and with fluorescence quantum yield of 18% are shown to be viable fluorescent probes for picric acid (PA). The SiNDs strongly bind PA, and their blue fluorescence is quenched. The distance between the donor and acceptor (R0 value) is calculated from fluorescence data to be 2.1nm. A fluorometric method was worked out that has a linear response in the 8nM to 50μM PA concentration range and a 0.92nM limit of detection. The method has a fast response (2min) and is well selective over other nitroaromatic compounds and metal ions. The average recoveries from spiked lake water samples ranged between 98.4 and 100.8%. Graphical abstract Water-dispersed fluorescent silicon nanodots (SiNDs) are synthesized using tetraethyl orthosilicate (TEOS) and trisodium citrate. Based on spectral overlap of fluorescent spectrum of SiNDs and absorption spectrum of picric acid (PA), fluorometric determination of PA at concentrations aslow as 0.92nM is achieved.