Electrogenerated chemiluminescence of Ag₂Te quantum dots and its application in sensitive detection of catechol

Ag₂Te quantum dots (QDs) were synthesized through ion-exchange method with CdTe QDs as precursors. The same size of Ag₂Te QDs can be obtained from the different sizes of precursors, which results in the similar fluorescent behaviors. The maximum FL peak of Ag₂Te QDs is red-shifted from 510 nm to 950 nm with the increase of ion-exchange time. Strong cathodic ECL of Ag₂Te QDs can be observed in neutral condition with K₂S₂O₈ as coreactant, which is much stronger than that of CdTe QDs. The ECL signals exhibit close relationship with the reaction time, the modified amount of QDs, and the K₂S₂O₈ concentration. Resonance energy transfer can occur between Ag₂Te QDs ECL and catechol resulting in the decreased ECL signals, which can be used in the sensitively detection of catechol. Under the optimal conditions, the decreased ECL signals varied linearly with the concentrations of catechol in the range of 1.0 × 10⁻⁹−1.0 × 10⁻⁵ mol L⁻¹ with a detection limit of 0.31 nM (3σ). The ECL sensor exhibited satisfied stability, repeatability and selectivity in the detection of catechol.