Fluorometric determination of hydrogen sulfide via silver-doped CdS quantum dots in solution and in a test strip

摘要

Silver-doped CdS quantum dots capped with mercaptoacetic acid (CdSAg-MAA QDs) were prepared and are shown to be a quenchable fluorescent probe for hydrogen sulfide (H2S). The optimized approach exhibits a linear response in the 0.01 to 500 mu M H2S concentration range and a 3.0 nM detection limit (RSD = 0.54 % for n = 5 at 10 nM of H2S). The estimated endogenous H2S levels in local wastewater were 45.4 mu M and 48.7 mu M and the assays were not responsive to various ions often present in water and wastewater. The method gave recoveries ranging from 98 to 102 % for the analysis of acidified wastewater spiked with H2S. Consequently, a simple colorimetric test strip was prepared by impregnating the filter paper with a mixture of CdSAg-MAA QDs and chitosan. The test strip exhibited good selectivity and sensitivity for the quantitation of H2S in local wastewater samples.