Size dependent active effect of CdTe quantum dots on pyrogallol-H2O2 chemiluminescence system for chromium(III) detection

Water-soluble CdTe quantum-dots (QDs) of different sizes and capped with mercaptosuccinic acid were prepared by the microwave irradiation method. The QDs can significantly enhance the chemiluminescence (CL) of the pyrogallol-H₂O₂ system. Those with a diameter of 3.8 nm produce the most intense CL. UV-vis, photoluminescence, and CL spectra were acquired in order to explore the effect. The results showed that the chromium(III) ion in the concentration range from 20 pM to 30 µM enhances CL, and this is exploited for its trace determination.The limit of detection (3σ) is 6 pM, with a relative standard deviation (n?=?11) of 1.7%. A continuous flow injection CL method was developed and applied to the determination of chromium(III) in tap water and lake water samples with satisfactory results.