Detection of Copper Ions Using Copper/Silver Nanoclusters
Date Issued
2010
Date
2010
Author(s)
Su, Yu-Ting
Abstract
This thesis focuses on devoloping a simple and homogeneous fluorescence assay—comprising 3-mercaptopropionic acid (MPA) with DNA-Cu/Ag nanoclusters (NCs) in aqueous solution—for the detection of Cu2+ ions. The sensing mechanism is based on the suppression of MPA induced fluorescence quenching of the DNA-Cu/Ag NCs by Cu2+. MPA-induced fluorescence quenching is due to changes in the DNA conformation as a result of the interactions between MPA and Cu/Ag clusters. The MPA-induced fluorescence quenching followed a typical characteristic of a Stern-Volmer plot and followed a static quenching mechanism. The presence of Cu2+ resulted in the oxidation of MPA to form disulfide, leading to suppression of the MPA-induced fluorescence quenching. The fluorescence of the DNA-Cu/Ag NCs in the presence of MPA increased upon increasing the concentration of Cu2+ over the range 5-200 nM. The DNA-Cu/Ag NC probe provided the limit of detection at a signal-to-noise of 3 of 2.7 nM for Cu2+ ions, with high selectivity (at least 2300-folds over tested metal ions). The practicality of this approach has been validated by the analyses of Montana soil and water samples (3 replicate measurements), showing the potential of the probe for detection of Cu2+ ions in environmental samples.
Subjects
copper/silver nanoclusters
3-mercaptopropionic acid
copper ions sensor
Type
thesis
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