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 11.5x10-8 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.
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