Abstract
Nanomaterials are becoming one of the most important classes of material research [1]. For example, quantum dots (QDs), especially water soluble QDs, have been used in many areas of research [2-3]. QDs are nanosize crystals of inorganic semiconductors with diameter in the range of 1-10 nm [4]. At such small sizes (close to or smaller than the dimensions of the exciton Bohr radius within the corresponding bulk material), these nanostructured materials behave differently from bulk solids, because of quantum-confinement effects [4]. As a result of quantum-confinement, they have unique optical and electronic properties such as broad excitation spectra and narrow, symmetric and tunable emission spectra [4]. Therefore, QDs have been used as novel luminescent sensors for chemical and biological species [5-8].This study fabricated cadmium telluride (CdTe) QDs from aqueous solution containing CdCl2 and Te precursor in presence of thioglycolic acid. The resulted QDs were characterized by using Uv-Vis. spectroscopy, photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The results demonstrated that low concentration, in nano-molar range, of Hg(II) ions could effectively quench the CdTe QDs fluorescence because Hg(II) ions form a stable complex with QDs coating (thioglycolic acid) which allow for an effective electron transfer from the QDs to the Hg(II). A linear response to Hg(II) ions in the concentration range from 0.625 to 8.0 n M was observed and the detection limit of this sensor was 0.625 nM and sensitivity was equal to 53.4 /nM. References Rosi NL, Mirkin CA Nanostructures in biodiagnostics. Chem Rev 105:1547–1562 (2005)Goldman ER, Balighian ED, Mattoussi H, Kuno MK, Mauro JM, Tran PT, Anderson GP (2002) Avidin: a natural bridge for quantum dot-antibody conjugates. J Am Chem Soc 124:6378–6382Chen Y, Rosenzweig Z (2002) Luminescent CdS quantum dots as selective ion probes. Anal Chem 74:5132–5138Alivisatos AP (1996) Perspectives on the physical chemistry of semiconductor nanocrystals. J Phys Chem 100:13226–13239Chan WCW, Maxwel DJ, Gao X, Bailey RE, Han M, Nie S (2002) Luminescent quantum dots for multiplexed biological detection and imaging. Curr Opin Biotechnol 13:40–46Zhang L, Ci Xu, Li B (2009) Simple and sensitive detection method for chromium(VI) in water using glutathione—capped CdTe quantum dots as fluorescent probes. Microchim Acta 166: 61–68Landes C, Burda C, Braun M, El-Sayed MA (2001) Photoluminescence of CdSe nanoparticles in the presence of a hole acceptor: n-Butylamine. J Phys Chem B 105:2981–2986Dong F, Hu K, Han H, Liang J (2009) A novel method for methimazole determination using CdSe quantum dots as fluorescence probes. Microchim Acta 165:195–201
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have