Surface plasmon resonance sensors using reduced graphene oxide-maghemite composite material for plumbum ion detection
As industries rapidly expand to meet the demands of massive dynamic development around the globe, plumbum contamination persists to be among the unsettled environmental issues we have today. The exposure to plumbum is known to cause severe systemic disease even at very low concentrations. The fea...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2017
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/70958/1/FK%202017%205%20-%20IR.pdf |
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| Summary: | As industries rapidly expand to meet the demands of massive dynamic development
around the globe, plumbum contamination persists to be among the unsettled
environmental issues we have today. The exposure to plumbum is known to cause
severe systemic disease even at very low concentrations. The fears from close of Pb2+
sources such as plumbing components to clinical applications and healthy
environment are the motivating for developing sensors. Over the past few years,
researchers have shown enormous interest in surface plasmon resonance (SPR) based
sensors due to its sensitivity and fast response for chemical, biological and
environmental sensing applications. The attached nanocomposite-sensing layer to a
plasmonic material has created vast integration for sensitivity and selectivity
enhancement in detection of heavy metals. This research work focuses on plumbum
(Pb2+) ion detection using SPR sensor have a new nanocomposite called reduced
graphene-maghemite (rGO/γ-Fe2O3) as a sensing layer. The main aspects of the study
are the sensing potentiality of rGO/γ-Fe2O3 in prism based SPR sensor technique,
protect the rGO/γ-Fe2O3 from degradation in water environment and finally detect
plumbum in water using rGO/γ-Fe2O3 at sub ppb detection limits. Preliminary studies
of the sensing layer when tested with hydrocarbon vapor show that it is sensitive
towards acetone as compared to ethanol, propanol and methanol, which highlights the
first demonstration of rGO/γ-Fe2O3 nanomaterial in optical sensing applications. For
heavy metal ion detection, its main challenge is the erosion of graphene-based
nanomaterial when the layer interacts with aqueous analyte. Therefore, a special
material matrix is required to enhance the adhesiveness of rGO/γ-Fe2O3 to the gold
(Au) layer on SPR and the combination of Au-rGO/γ-Fe2O3 sensing layer and 1-Ethyl-
3-(3-dimethylaminopropyl)carbodiimide/ N-Hydroxysuccinimide/ (EDC/NHS) as a
protection layer is used in the sensor structure. The optimized thicknesses of Au,
rGO/γ-Fe2O3 and EDC/NHS are 41, 8.75 and 4 nm, respectively and its limit of
detection for Pb2+ ions is 0.001 ppm in static water conditions. The limit of detection
is further enhanced to 0.3 ppb by adopting the water circulation method. Selectivity of
Pb2+ ions is greatly enhanced, by replacing EDC/NHS with polyvinylchloride (PVC). This work highlights the advantages of rGO/γ-Fe2O3 nanocomposite as the sensing
layer on an SPR based sensor for the detection of Pb2+ ions in water. Its sensing
performance has shown great potential in matching the need for a robust, cheap,
sensitive and selective sensing method to detect heavy metals and help curb the
environmental problem. The quantitative research findings are 1.1-degree angle shift
in 10% concentration vapor acetone, EDC/NHS enhanced the sensing layer to work
under water circulation for 50 experiments and detection of plumbum ions in water at
concentration 0.3 ppb. |
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