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

Oluwasesan Adegoke, Patricia B. C. Forbes (Lead / Corresponding author)

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

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 unconjugated 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 µg/L was obtained for Phe under optimum conditions, whilst the LOD of Ant, Py and Naph were estimated to be ~0.26 µg/L. The fluorescence detection mechanism is proposed.

Original languageEnglish
Pages (from-to)780-788
Number of pages9
JournalTalanta
Volume146
Early online date16 Jun 2015
DOIs
Publication statusPublished - 1 Jan 2016

Keywords

  • Absorption, Physicochemical
  • Adsorption
  • Cysteine/chemistry
  • Environmental Pollutants/analysis
  • Fluorescent Dyes/chemistry
  • Nanocomposites/chemistry
  • Oxides/chemistry
  • Polycyclic Aromatic Hydrocarbons/analysis
  • Quantum Dots/chemistry
  • Solubility
  • Spectrometry, Fluorescence
  • Water/chemistry

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