Preparation of ZnS:Ni/ZnS quantum dots with core/shell structure and application for detecting cefoperazone–sulbactam

• ZnS:Ni/ZnS QDs were synthesized easily with nontoxic.
• It shows fluorescent characteristic with good water-solubility and stability.
• ZnS:Ni/ZnS QDs was firstly used as fluorescent probe to detect CPZ–SBT.
• This novel method is sensitive with good selectivity and a low detection limit.

ZnS:Ni quantum dots (QDs) have been synthesized via a water-soluble route, which were coated by ZnS shell through surface modification to give ZnS:Ni/ZnS QDs. The QDs were characterized by atomic force microscope, X-ray diffraction, infrared spectrometry and fluorescent spectrometry. Then, a novel method for the determination of cefoperazone–sulbactam (CPZ–SBT) in aqueous solutions has been developed based on the enhancement of fluorescence of ZnS:Ni/ZnS QDs in the presence of CPZ–SBT. Under the optimal conditions, the enhanced fluorescence intensity (ΔF) was proportional to CPZ–SBT concentration in the range of 8.0 × 10−6–1.0 × 10−4 g/L with a detection limit of 1.0 × 10−7 g/L. The method was employed for the determination of CPZ–SBT in sample to give satisfactory result. Compared with others, this method was more sensitive, fast and simple with low limit detection.

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