Development of an electrochemical immunosensor for environmental monitoring of polychlorinated biphenyls (PCBs) in soil environment

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dc.check.date2025-09-30
dc.contributor.advisorMoore, Eric
dc.contributor.authorAlsefri, Samiaen
dc.contributor.funderMinistry of Education – Kingdom of Saudi Arabi
dc.date.accessioned2024-05-30T10:30:12Z
dc.date.available2024-05-30T10:30:12Z
dc.date.issued2023
dc.date.submitted2023
dc.descriptionPartial Restriction
dc.description.abstractPolychlorinated biphenyls, PCBs are a type of chemical contaminant known as persistent organic pollutants (POPs). They consist of biphenyl molecules covalently bonded with one to ten chlorine atoms. PCBs pose a threat to ecosystems and food safety due to their high toxicity, long-term stability, poor degradation, and bioaccumulation. The current methods, although sensitive, have their limitations, for example, time-consuming, laborious, and costly. Further, the instrumentation cannot be used for on-site analysis. The aim of this research is to develop a novel electrochemical method that will be capable of providing a direct, portable, cost-effective, and easy method for analysing and monitoring PCBs in the environment. For the first time, a self-assembled monolayer was used to modify an electrode as a method for fabricating a transducer for detection of PCBs by using a gold electrode, it was modified with 11-mercaptoundecanoic acid (11-MUA), and the activation of the carboxylic acid terminal was performed by cross-linking 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hyrodsuccinmide (NHS). The electrochemical behaviour of the electrode was investigated by CV (Cyclic Voltammetry), LSV (Linear Sweep Voltammetry) and EIS (Electrochemical Impedance Spectroscopy) using a ferrocyanide/ferricyanide redox pair. It was found that the indirect competitive assay showed the best performance for Aroclor1254 detection, with a commercial Polyclonal chicken antibody (IgY) specific to PCB was used as primary antibody. The limit of detection was found at 0.20 ng/ml using bare gold electrode. However, the sensitivity of the sensor was increased after the electrode surface modification was found at 0.09 ng/ml. A novel electrochemical immunosensor method showed a good performance with a 3-fold decrease in sensitivity achieved after the surface modification. The electrode coated with coating conjugate was found stable for more than 25 days at 4 ˚C. In conclusion, this Ph.D. thesis demonstrates that the integration of electrochemical techniques with immunoassay methods can achieve detection limits as low as required for in-situ and real-time analysis of soil samples. It was found that the electrochemical immunosensor method showed better results compared to ELISA and that was verified with GC-MS. The usage of this a novel electrochemical immunosensor as a complement to the electrochemical studies not only enhanced the quality of the research but also contributed to the construction and improvement of immunosensors. As a result, they represent an accurate and a new robust method that can be applied to microsensors and microfluidic systems for the effective control and prevention of PCBs in the environment.en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationAlsefri, S. A. 2023. Development of an electrochemical immunosensor for environmental monitoring of polychlorinated biphenyls (PCBs) in soil environment. PhD Thesis, University College Cork.
dc.identifier.endpage278
dc.identifier.urihttps://hdl.handle.net/10468/15959
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2023, Samia Abdullah Alsefri.
dc.rights.urihttps://creativecommons.org/licenses/by-nc/4.0/
dc.subjectPolychlorinated biphenylsl
dc.subjectDisposable screen-printed gold electrode
dc.subjectLinearsweepvoltam metry
dc.subjectImmunosensors
dc.subjectImmunoassays
dc.subjectSelf-assembledmonolayers
dc.titleDevelopment of an electrochemical immunosensor for environmental monitoring of polychlorinated biphenyls (PCBs) in soil environment
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD - Doctor of Philosophyen
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