On-off-on fluorescent silicon nanoparticles for recognition of chromium(VI) and hydrogen sulfide based on the inner filter effect

A highly sensitive and selective fluorescence sensor for detection of chromium(VI) and hydrogen sulfide was developed by using silicon nanoparticles (SiNPs) as probe. The fluorescence of SiNPs was effectively quenched by Cr(VI) via the inner filter effect. Upon addition of hydrogen sulfide, the fluorescence of SiNPs was recovered due to the oxidation-reduction between Cr(VI) and H2S. Under optimal conditions, the wide linear response ranges were obtained over the range of 0.1-200 μM and 0.1-200 μM with the low detection limits of 28 nM and 22 nM for Cr(VI) and H2S, respectively. The sensing platform was successfully applied to determination of Cr(VI) and H2S in real samples.