Highly selective circular dichroism sensor based on D-penicillamine/ cysteamine cadmium sulfide quantum dots for copper (II) ion detection
Kessarin Ngamdee, Kanokwan Chaiendoo, Chatree Saiyasombat, Wutthikrai Busayaporn, Somlak Ittisanronnachai, Vinich Promarak, Wittaya Ngeontae
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
A highly selective circular dichroism sensor based on cysteamine-capped cadmium sulfide quantum dots (Cys-CdS QDs) was successfully developed for the determination of Cu2+. Basically, the Cys-CdS QDs are not active in circular dichroism spectroscopy. However, the circular dichroism probe ([email protected] QDs) can be simply generated in situ by mixing achiral Cys-CdS QDs with D-penicillamine. The detection principle was based on measuring the circular dichroism signal change upon the addition of Cu2+. The strong CD signal of the [email protected] QDs dramatically decreased in the presence of Cu2+, while other cations did not result in any spectral changes. In addition, the degree of the CD signal decrease was linearly proportional to the concentration of Cu2+ in the range of 0.50–2.25 μM (r2 = 0.9919) with a detection limit of 0.34 μM. Furthermore, the proposed sensor was applied to detect Cu2+ in drinking water samples with %recovery values of 102–114% and %RSD less than 6%.
Circular dichroism, Cotton effect, Ligand binding, Sensors, Nanostructures, Materials