Ultrasensitive and rapid lead sensing in water based on environmental friendly and high luminescent L-glutathione-capped-ZnSe quantum dots.

Water-soluble and high luminescent l-glutathione-capped-ZnSe quantum dots (QDs) were applied for ultrasensitive Pb(II) detection. l-glutathione-capped-ZnSe QDs were synthesized by a facile colloid aqueous phase route. It is characterized by transmission electron microscopy, X-ray powder diffraction spectrometry, Fourier transform infrared spectrometry, Ultraviolet-visible spectrometry and fluorescence spectrometry. Quantum yields of l-glutathione-capped-ZnSe QDs could reach 50.1% without post irradiation. The fluorescence quenching of the l-glutathione-capped-ZnSe QDs depended on the concentration, pH and reaction time of the Pb(II) solution. The possible mechanism of fluorescence of l-glutathione-capped-ZnSe QDs quenched by Pb(II) was discussed in detail. Under optimal conditions, the quenched fluorescence intensity increased linearly with the concentration of Pb(II) in the range of 1.0×10(-8)∼8.0×10(-7)mol/L. The limit of detection for Pb(II) was 0.71 nmol/L. This developed method is demonstrated to contain improved sensitive and selective characteristics for the detection of trace Pb(II) in water.