Turn-on electrochemiluminescence sensing of Cd2+ based on CdTe quantum dots

• ECL of QDs was quenched by S2− and restored by following addition of Cd2+.
• ECL turn-on sensing of Cd2+ was proposed.
• The sensing mode was sensitive and selective.
• Linear range: 6.2 nM–3.2 μM (R = 0.999), LOD: 2.1 nM.

A simple and sensitive method for the detection of cadmium ion was proposed based on the electrochemiluminescence (ECL) of thioglycolic acid capped-CdTe quantum dots (CdTe QDs). The ECL of CdTe QDs was firstly quenched by introduction of S2− and was restored due to following addition of Cd2+, on the basis of which, a “turn-on” ECL method for the detection of Cd2+ was demonstrated. The ECL of CdTe QDs exhibited linear response toward Cd2+ concentration in the range from 6.3 nM to 3.4 μM (R = 0.999) with a detection limit of 2.1 nM. The proposed assay was simple, sensitive, selective, and practicable in real water samples.

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