Fluorescent sensing of sulfide ions based on papain-directed gold nanoclusters

Abstract

A sensitive and selective method has been developed for the determination of sulfide ions (S 2À ) based on S 2À triggered fluorescence quenching of papain-directed Au nanoclusters. Under the optimized experimental conditions, the proposed method facilitated the determination of S 2À in the linear range 0.5-80.0 mM; the limit of detection was 0.38 mM at a signal-to-noise ratio of 3. In addition, the fluorescence intensity decreased selectively in response to S 2À relative to other ions. Based on multiple analyses, it is proposed that the fluorescence was quenched through the unique reactions between S 2À and the Au atoms/ions, and that the formation of Au 2 S induced aggregation of the Au nanoclusters.The practicality of the proposed method for the determination of S 2À in natural water samples was verified. The results were in good agreement with those determined by the methylene blue colorimetric method. This new method may broaden the scope of techniques available for the determination of S 2À .

Direct and sensitive detection of sulfide ions based on one-step synthesis of ionic liquid functionalized fluorescent carbon nanoribbons

“…Thus, IL-CNRs based method is sensitive enough to detect the maximum allowable level of S 2− ions in drinking water recommended by World Health Organization. 42,43 As shown in Table S1 (ESI † ), the detection limit obtained with the present method was lower than those obtained by carbon dots (CDs)-Ag + , 44 covalent linking fluorescein isothiocyanate with branched-polyethylenimine (PEI-FITC), 43 triarylimidazole chromophore (TPI-H)-Cu 2+ , 45 Au nanoclusters, 46 lysozyme-stabilized silver nanoclusters (Lys-Ag NCs), 47 graphene quantum dot (GQDs)-Cu 2+ , 48 but higher than that obtained using Cu nanoclusters, 49,50 Au nanoclusters-Ce( iii ), 51 and silver nanoparticles capped with carbon dots (AgNPs-CDs). 52 …”

Bio-Mediated Synthesis of Nanoparticles for Fluorescence Sensors

“…Inorganic anions, such as cyanide (CN -), sulfide (S 2-), and (nitrite) NO 2-, retain the damaging influence on ecological systems as well as human health. 108,[132][133][134][135][136][137][138][139][140][141][142][143] Among them, acquaintance to high levels of CN-leads to the compensations of organs and skin via the suppression of oxygen transportation. 108,[132][133][134][135][136] Besides, hydrogen cyanide (HCN) is practical to be liberated from enzyme-catalyzed hydrolysis of cyanogenic glycosides that are commonly present in edible foods, like bamboo and cassava.…”

Revealing the Active Site of Gold Nanoparticles for the Peroxidase-Like Activity: The Determination of Surface Accessibility

“…These results implied that AuNPs with various surface coatings should have the same active site of Au(I), and thus their peroxidase-like activities could all be inhibited by S 2− . It should be noted that excess S 2− can also lead to aggregation of AuNPs [18,19], and thus the active sites may be reduced by increasing the size of AuNPs. To avoid this problem, the added amount of S 2− was carefully controlled to inhibit nearly 90% of the peroxidase-like activity (see Figure S2).…”