In situ anodic stripping of Cd(II) from CdS quantum dots for electrochemical sensing of ciprofloxacin

In this work, CdS quantum dots (QDs) were proposed as electrochemical sensing materials for ciprofloxacin (CIP) determination for the first time. The CdS QDs-modified glassy carbon electrode (GCE) exhibited a well-defined anodic stripping response in acidic solution, attributed to the release of Cd(II) ions from CdS QDs. The influences of supporting electrolyte and CdS QDs concentration on the response of CdS QDs-modified electrode were investigated and optimized. When CIP was added into the solution, the anodic stripping current of Cd(II) on CdS QDs/GCE decreased due to the complexation of CIP with in situ generated Cd(II) ions from CdS QDs. A linear relationship existed between the anodic stripping voltammetric response of CdS QDs/GCE and CIP concentration in the range from 1.0   ×   10 −7 to 1.0   ×   10 −5   mol   L −1 . The detection limit (3S/N) was 2.2   ×   10 −8   mol   L −1 . The applicability of the CdS QDs-modified electrode for CIP determination was demonstrated in biological fluids.