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Multi-array sensor technology for polycyclic aromatic hydrocarbons screening in wastewater
Expanded Title:PAHs are highly hydrophobic species that are readily absorbed from the gastrointestinal tract of humans and other mammals, where they particularly deposit in the fatty tissue. Cytochrome P450-mediated mixed function oxidase systems are primarily responsible for oxidation or hydroxylation of these PAHs. Whilst there are numerous well known natural and anthropogenic sources of PAHs it is perhaps less well known that PAHs can be produced biologically by certain plants and bacteria or formed during the degradation of plant material. Polyaromatic hydrocarbons are not the easiest analyse species to detect based on redox chemistry. Chemical oxidation appears to be a minor PAH degradation mechanism under most environmental conditions, directly affected by molecular weight and structure of the compound, its physical state, temperature, and the strength of the oxidizing agent all impact the outcome. The novel polymer electro-catalysts developed in this work provided for a wide range of new catalysts to be implemented in a controlled electro-catalytic approach. Unlike total degradation that may be achieved by high voltage electrolysis, electro-catalysis seeks to identify unique signals for identification of analyte species and intermediates that may be used for quantification and the understanding of degradation mechanisms. The electro-catalysts were developed from Schiff base monomers synthesised by aldol condensation chemistry to produce reliable product in good yield. These polymers were then deposited in situ at commercial screen printed electrode arrays to evaluate and quantify the oxidation current generated by electrochemical oxidation of selected PAH species. For the first time in this project we have reported on the electrochemical redox signals reported at commercial screen printed carbon electrodes and novel polymer coated electrodes, of a wide range of the most significant PAHs, in a comprehensive manner. Both the materials aspects of the actuator type polymers as well as the electrochemical signal reporting of PAHs, listed by the U.S. EPA as priority pollutants, are completely novel aspects of the research concluded. The novel electro-catalysts were then assemble in a multi-array configuration as a pre-text to the development of a fully independent electro-analytical tool for discrimination and quantification of PAHs in mixed samples. An enhancement of electrochemical transduction may be effected by incorporating a suitable electron wiring effect by doping the polymers with metal nanoparticles or other high surface area nanomaterials. Any development to improve the electrochemistry of the materials, will directly benefit the overall analytical protocol developed here. However the systematic approach demonstrated in this work is ground breaking and paves the way for all future developments in this regard.
Date Published:01/03/2018
Document Type:Research Report
Document Keywords:Health, Nutrient Management, Water Quality
Document Format:Report
Document File Type:pdf
Research Report Type:Standard
WRC Report No:2454/1/17
ISBN No:978-1-4312-0966-8
Authors:Baker PGL
Project No:K5/2454
Originator:WRC
Organizations:University of Western Cape ,South Africa
Document Size:1 468 KB
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