TY - JOUR
T1 - L-cysteine-capped core/shell/shell quantum dot-graphene oxide nanocomposite fluorescence probe for polycyclic aromatic hydrocarbon detection
AU - Adegoke, Oluwasesan
AU - Forbes, Patricia B. C.
N1 - A postdoctoral fellowship offered by the University of Pretoria is gratefully appreciated by O. Adegoke. This work is based on research supported in part by the National Research Foundation of South Africa, Grant Numbers: 90720 and 93394 (P. Forbes), as well as the Department of Science and Technology (DST), South Africa, through the Photonics Initiative of South Africa (grant PISA-15-DIR-06), and the Water Research Commission, South Africa (grant K5-2438).
PY - 2016/1/1
Y1 - 2016/1/1
N2 - 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.
AB - 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.
KW - Absorption, Physicochemical
KW - Adsorption
KW - Cysteine/chemistry
KW - Environmental Pollutants/analysis
KW - Fluorescent Dyes/chemistry
KW - Nanocomposites/chemistry
KW - Oxides/chemistry
KW - Polycyclic Aromatic Hydrocarbons/analysis
KW - Quantum Dots/chemistry
KW - Solubility
KW - Spectrometry, Fluorescence
KW - Water/chemistry
U2 - 10.1016/j.talanta.2015.06.023
DO - 10.1016/j.talanta.2015.06.023
M3 - Article
C2 - 26695330
SN - 0039-9140
VL - 146
SP - 780
EP - 788
JO - Talanta
JF - Talanta
ER -