L-Cysteine-capped core/shell/shell quantum dot-graphene oxide nanocomposite fluorescence probe for polycyclic aromatic hydrocarbon detection

TALANTA

卷:146

Article

Adegoke, Oluwasesan¹  Forbes, Patricia B. C.¹ 

[1] Univ Pretoria, Fac Nat & Agr Sci, Dept Chem, ZA-0002 Pretoria, South Africa

关键词: Quantum dots;    Graphene oxide;    Adsorption;    Photoluminescence;    Polycyclic aromatic hydrocarbon;    Fluorescence sensor;   

DOI  :  10.1016/j.talanta.2015.06.023

来源: Elsevier

【 摘 要 】

Environmental pollutants, such as the polycyclic aromatic hydrocarbons (PAHs), become widely distributed in the environment after emission from a range of sources, and they have potential biological effects, including toxicity and carcinogenity. In this work, we have demonstrated the analytical potential of a covalently linked L-cysteine-capped CdSeTe/ZnSe/ZnS core/shell/shell quantum dot (QD)-graphene oxide (GO) nanocomposite fluorescence probe to detect PAH compounds in aqueous solution. Water-soluble L-cysteine-capped CdSeTe/ZnSe/ZnS QDs were synthesized for the first time and were covalently bonded to GO. The fluorescence of the QD-GO nanocomposite was enhanced relative to the un-conjugated QDs. Various techniques including TEM, SEM, HRSEM, XRD, Raman, FT-IR, UV/vis and fluorescence spectrophotometry were employed to characterize both the QDs and the QD-GO nanocomposite. Four commonly found priority PAH analytes namely; phenanthrene (Phe), anthracene (Ant), pyrene (Py) and naphthalene (Naph), were tested and it was found that each of the PAH analytes enhanced the fluorescence of the QD-GO probe. Phe was selected for further studies as the PL enhancement was significantly greater for this PAH. A limit of detection (LOD) of 0.19 mu g/L was obtained for Phe under optimum conditions, whilst the LOD of Ant, Py and Naph were estimated to be similar to 0.26 mu g/L. The fluorescence detection mechanism is proposed. (C) 2015 Elsevier B.V. All rights reserved.

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