A rapid, simple and sensitive label-free fluorescence method was developed for the determination of trace amounts
of an important drug, heparin. This new method was based on water-soluble glutathione-capped CdTe quantum dots (CdTe QDs)
as the luminescent probe. CdTe QDs were prepared according to the published protocol and the sizes of these nanoparticles were
verified through transmission electron microscopy (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS) with an
average particle size of about 7 nm. The fluorescence intensity of glutathione-capped CdTe QDs increased with increasing hepa-
rin concentration. These changes were followed as the analytical signal. Effective variables such as pH, QD concentration and
incubation time were optimized. At the optimum conditions, with this optical method, heparin could be measured within the
range 10.0 – 200.0 ng mL
1 with a low limit of detection, 2.0 ng mL
1 . The constructed fluorescence sensor was also applied
successfully for the determination of heparin in human serum. Copyright © 2015 John Wiley & Sons, Ltd.