A potential visual fluorescence probe for ultratrace arsenic (III) detection by using glutathione-capped CdTe quantum dots.

The interaction between mercaptoacetic acid (MA)-capped CdTe QDs, MA-capped CdTe/ZnS QDs or glutathione (GSH)-capped CdTe QDs with As(III) was studied using fluorescence spectrometry. As (III) has a high-affinity to reduced-GSH to form As(SG)(3), and the emission of the GSH-capped CdTe QDs (λ(em.) =612 nm) is quenched effectively. Thus, a novel fluorescence spectrometric method was developed for As (III) determination by using GSH-CdTe QDs. Under optimal conditions, the quenched fluorescence intensity (F(0)/F) increased linearly with the concentration of As (III) ranging from 5.0 × 10(-6) to 25 × 10(-5) mol L(-1). The limit of detection (3σ) for As (III) was found to be 2 × 10(-8) mol L(-1). This method is potentially useful in visual detection of As (III) under irradiation of the ultraviolet light.