Pure zinc sulfide quantum dot as highly selective luminescent probe for determination of hazardous cyanide ion

• Preparation of functionalized ZnS quantum dots in aqueous media
• Highly selective quantum dot based luminescent probe for determination of cyanide
• Fast and sensitive determination of hazardous CN− by fluorescence quenching

A rapid and simple fluorescence method is presented for selective and sensitive determination of hazardous cyanide ion in aqueous solution based on functionalized zinc sulfide (ZnS) quantum dot (QD) as luminescent prob. The ultra-small ZnS QDs were synthesized using a chemical co-precipitation method in the presence of 2-mercaptoethanol (ME) as an efficient capping agent. The prepared pure ZnS QDs was applied as an optical sensor for determination of cyanide ions in aqueous solutions. ZnS nanoparticles have exhibited a strong fluorescent emission at about 424 nm. The fluorescence intensity of QDs is linearly proportional to the cyanide ion concentration in the range 2.44 × 10− 6 to 2.59 × 10− 5 M with a detection limit of 1.70 × 10− 7 M at pH 11. The designed fluorescent sensor possesses remarkable selectivity for cyanide ion over other anions such as Cl−, Br−, F−, I−, IO3−, ClO4−, BrO3−, CO32 −, NO2−, NO3−, SO42 −, S2O42 −, C2O42 −, SCN−, N3−, citrate and tartarate with negligible influences on the cyanide detection by fluorescence spectroscopy.

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