A highly sensitive dual-readout assay for perfluorinated compounds based CdTe quantum dots

Perfluorooctanoic acid (PFOA) and Perfluorooctane sulfonate (PFOS) are two typical perfluorinated compounds (PFCs) that poss potential ecological toxicity . In this work, a fluorescence and resonance light scattering (RLS) dual-readout strategy for the detection of PFCs at picomole level based on the water-soluble CdTe quantum dots (CdTe QDs) has been proposed. It is found that the CdTe QDs exhibit a quenching in the presence of PFCs and thus serve as useful probes for PFCs. The linear ranges are 0.032 – 10.0 nM with a limit of detection(LOD) of 32.02 pM for PFOA and 0.044 – 15.0 nM with a LOD of 43.96 pM for PFOS, respectively. Meanwhile, PFCs can form complexes with CdTe QDs in acid medium , resulting in remarkable RLS signals.  The enhanced RLS intensities are in proportion to the concentrations of PFOA and PFOS, respectively. And the linear ranges are 0.048 – 5.0 nM with a LOD of 47.78 pM for PFOA, and 0.057 – 5.0 nM with a LOD of 56.72 pM for PFOS, respectively.  This dual-mode detection increases the reliability of the measurement. The proposed method is simple, sensitive and cost-effective, with  potential  applications in environmental monitoring and assessment.