Immobilization of phosphorescent quantum dots in a sol–gel matrix for acetone sensing

Quantum dots (QDs) are semiconductor nanoparticles (NPs) that are increasingly used in optical sensing applications due to their exceptional optoelectronic properties. When such nanocrystals are doped with certain metal impurities, a phosphorescence-like emission can be obtained, allowing the development of novel robust and highly selective sensing phases (it is possible to perform time resolved measurements enabling a simple discrimination between the luminescence emission from the QDs from the background fluorescence of the sample, in which luminescent lifetime is shorter). s context, a phosphorescent sensing material for acetone control in water media has been developed based on the immobilization of phosphorescent quantum dots in an inorganic sol–gel solid matrix. ch purpose, colloidal manganese-doped ZnS nanoparticles (Mn:ZnS QDs) surface-modified with l-cysteine (for water solubilisation) were synthesised. The Mn:ZnS QDs exhibit an intense room temperature phosphorescence (RTP) emission in aqueous media even in the presence of dissolved oxygen. Further, a simple and general procedure is proposed to incorporate the colloidal l-cysteine Mn:ZnS QDs in a sol–gel matrix. ation of the developed sensing material to analytical control of acetone dissolved in contaminated water samples was performed based on measurement of the quenching effect of the analyte on the QDs phosphorescence emission. The sol–gel procedure (e.g. nature and concentration of the silica precursors used) employed for immobilization of the QDs was optimized trying to obtain the best analytical features for detection of acetone. The optimized sensing material showed a high selectivity of the sensing material towards acetone. The linear range of the developed methodology turned out to be at least up to 50% acetone:water (v/v) with a detection limit (DL) for acetone dissolved in aqueous medium of 0.16% acetone:water (v/v). The developed sensing phase was finally applied for acetone determination in different spiked water samples, and the recoveries fall in the range of 93–109%.