Use of MPA-capped CdS quantum dots for sensitive detection and quantification of Co2+ ions in aqueous solution - École polytechnique Access content directly
Journal Articles Analytica Chimica Acta Year : 2018

Use of MPA-capped CdS quantum dots for sensitive detection and quantification of Co2+ ions in aqueous solution

Abstract

Water soluble CdS quantum dots (QDs) were synthesized by a simple aqueous chemical route using mercaptopropionic acid (MPA) as a stabilizer. These QDs had a fluorescence emission band maximum at 540 nm with a FWHM ∼130 nm and a quantum yield of ∼12%. Transmission electronic microscopy images were used to determine the QD diameter of 8.9 ± 0.4 nm. From this value we calculated the molecular mass M(QD) = 1.17 × 106 g mol-1 and the extinction coefficient at the band edge (450 nm) ε450 = 4.7 × 106 cm-1 M-1, which allowed to determine the true molar concentration of 17 nM for spectroscopic measurements in solution. The fluorescence intensity of MPA-CdS QDs was quenched only in the presence of Co2+ ions, but not in the presence of thirteen other metal cations. The fluorescence quenching of MPA-CdS QDs appeared proportional to the Co2+ concentration in the range 0.04-2 μM. Based on a fluorescence peak position and a lifetime both independent from Co2+ concentration, the quenching mechanism of MPA-CdS QDs appeared static. Because the strong electronic absorption of Co2+ overlaps the emission of QDs, our results can be explained by Förster energy transfer from QD to the bound Co2+ cations.
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Dates and versions

inserm-04413423 , version 1 (23-01-2024)

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Naim Bel Haj Mohamed, Nassim Ben Brahim, Randa Mrad, Mohamed Haouari, Rafik Ben Chaâbane, et al.. Use of MPA-capped CdS quantum dots for sensitive detection and quantification of Co2+ ions in aqueous solution. Analytica Chimica Acta, 2018, 1028, pp.50 - 58. ⟨10.1016/j.aca.2018.04.041⟩. ⟨inserm-04413423⟩
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