Development of fluorescence sensor and paper chips based on EDTA etched-CdTe@CdS QDs for the selective and sensitive detection of Cd(II) in rice samples

EDTA-etched CdTe@CdS QDs were used as the specific recognition element and signal probe of a fluorescence sensor or paper chip for the highly sensitive detection of Cd(II) with an electronic eye device as readout. The results showed that the CdTe@CdS QDs were successfully synthesized with a typical core–shell structure. Under the optimum conditions, the EDTA-etched CdTe@CdS QDs sensor achieved the sensitive detection of Cd(II) with a detection limit of 0.092 μM and a concentration range of 0.44–6.67 μM. The paper chips based on the EDTA-etched CdTe@CdS QDs sensor had a visual cut-off value of 0.44 μM with a short detection time (<15 min). The proposed method also exhibited excellent stability, high specificity, and good recovery for Cd(II) in real rice samples. These results suggested that the EDTA-etched CdTe@CdS QDs provide a promising platform for on-site and visual detection of Cd(II) in rice samples.