Use of water-soluble PbS quantum dots as fluorescent probe in sensing copper(Ⅱ)

摘要

In this paper, we report a new facile method for the synthesis of water-soluble PbS quantum dots (QDs), using dihydrolipoic acid (DHLA) as a stabilizer. The prepared QDs were characterized by optical techniques and high-resolution transmission electron microscopy (TEM). Next, these water-soluble luminescent PbS QDs were further used to detect copper (Ⅱ). The obtained experimental results show that the fluorescence of the PbS QDs could be markedly quenched by Cu(Ⅱ) whereas approximate concentrations of other physiologically relevant cations, such as Zn(Ⅱ), Ca(Ⅱ), Mg(Ⅱ), Mn(Ⅱ), Na(I) and K(Ⅰ) etc., almost did not interfere with the fluorescence quenching progress of copper ions. Based on this, a simple and rapid method for Cu(Ⅱ) determination was developed. Under optimal conditions, the response was linearly proportional to the copper(Ⅱ) concentration in the range of 1 to 11.5×10~-8 mol-L~-1, with a correlation coefficient of 0.995. Hence, aqueous DHLA-stabilized PbS QDs may be a promising fluorescent probe in sensing copper(II) selectively.