Electrochemical detection of quantum dots by stabilization of electrogenerated copper species

- Copper species are stabilized at electrodes modified with quantum dots
- Amount of quantum dots on the electrode affected the copper voltammetric response
- A method for the determination of quantum dots was optimized
- Limit of detection was in the order of hundreds of amol of nanoparticles

The determination of quantum dots is of particular interest as they are frequently used as labels in electrochemical biosensors. In this paper, we describe a method for the detection of very low concentrations of quantum dots using the voltammetric response of copper in ammonia solution. Copper species electrogenerated on the electrode surface are stabilized by the nanoparticles, preventing their oxidation by dissolved oxygen, and a relationship between the concentration of the nanoparticles and the copper voltammetric response can thus be obtained. The reported method shows a linear range between 0.05 and 2 nM of quantum dots, with a limit of detection in the order of 9 × 107 nanoparticles. This method could be employed to improve the detection limit of electrochemical biosensors using quantum dots as labels.

144