Determination of superoxide anion radical by modified CdTe quantum dots

Abstract

Abstract A novel fluorescence probe for determination of superoxide anion radical (O2 −) was developed with CdTe quantum dots(QDs) modified by thiophene-2-formaldehyde shrinked l -cysteine Schiff base, which was characterized by Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), ultraviolet-visible (UV–vis) and fluorescent spectrum. The particle size of CdTe QDs was 3.1 nm as confirmed by X-ray powder diffraction pattern (XRD) and Transmission Electron Microscope (TEM) in presence of β-cysteamine (CA). The fluorescent results showed that the fluorescence intensity of CdTe QDs was decreased with modified Schiff base at 305 nm, but enhanced at 610 nm with O2 − and showed an apparent linear dependence in the concentration scope of 2.0 × 10−5–1.0 × 10−4 mol L−1 (r = 0.9934) with a detection limit of 1.8 × 10−6 mol L−1, which exhibited high selectivity and stability towards O2 −.