Fluorescence-based selective sensing of 1,2,4-trihydroxybenzene using histidine-stabilized ZnS nanospheres

In this paper, histidine-stabilized ZnS nanospheres have been used as a fluorescent probe for the selective detection of 1,2,4 –trihydroxybenzene (1,2,4 –THB). 1,2,4 –THB quenches the fluorescence of ZnS nanospheres in the 0.2–1.0 μM concentration range. Two other isomers of the analyte (namely, 1,2,3 –THB and 1,3,5 –THB) do not quench the fluorescence of the ZnS nanospheres in the above mentioned concentration range. A charge transfer complex is formed between 1,2,4 –THB and the histidine molecules surrounding the ZnS nanospheres. Due to its electron-rich character, 1,2,4 –THB acts as an electron donor while histidine acts as an electron acceptor. The limit of detection (LOD) of 1,2,4 –THB using this method is 0.28 μM. This fluorescence-based method has the potential to be used for the detection of 1,2,4 –THB in biological samples since the experiments have been carried out in an aqueous medium at pH 7.2. (papers)