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The binding ability of ochratoxin A using nano-enabled materials to mitigate exposureYoumbi, Thierry Fonkui 13 October 2014 (has links)
M.Tech. (Biotechnology) / Please refer to full text to view abstract
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Development of polypyrrole films by electrochemical imprinting for molecular recognition of ochratoxin A - applications in surface plasmon resonace sensor and micro solid phase extraction /Yu, Jorn Chi-Chung. January 1900 (has links)
Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 151-159). Also available in electronic format on the Internet.
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Avaliação da presença de ocratoxina A em alguns alimentos e bebidas nacionais / Evaluation of the presence of ochratoxin A in some brasilian food and beveragesVieira, Ana Paula 07 June 2005 (has links)
Orientador: Lucia Maria Valente Soares / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T15:48:34Z (GMT). No. of bitstreams: 1
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Previous issue date: 2005 / Doutorado / Doutor em Ciência de Alimentos
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Application of catalysts and nanomaterials in the design of an electrochemical sensor for ochratoxin AFlanagan, Shane Patrick 06 December 2010 (has links)
Ochratoxin A is the most potent chlorinated derivative of the ochratoxin group, consisting of a 5'-chlorinated dihydroisocoumarin moiety linked by an amide bond to l-phenylalanine. Produced as a secondary fungal metabolite by several species of Aspergillus and Penicillium, ochratoxin A has been shown to readily contaminate a large variety of commodities including cereals, groundnuts, dried fruit, spices and coffee. This has led to widespread contamination of ochratoxin in wine, beer, milk and meat products. As ochratoxin A is a potent nephrotoxin exhibiting teratogenic and carcinogenic properties, the development of a rapid screening platform for the cost effective control of ochratoxin A content in foodstuffs is therefore required. The evaluation of metallophthalocyanine and carbon nanotube electrode modification toward the development of a nanostructured biosensor capable of enhancing the electrochemical detection of ochratoxin A in complex media is presented. Cyclic voltammetry at a glassy carbon electrode allowed for the optimization of detection parameters including pH and type of supporting electrolyte. Britton-Robinson buffer was found to be the most suitable supporting electrolyte in terms of sensitivity and reproducibility obtaining a LOD of 0.28 μM as determined by differential pulse voltammetry. Subsequent analysis determined the dependence of OTA oxidation on pH in acidic media which proceeds with the transfer of two electrons to form a quinone/hydroquinone couple shown to adsorb to the electrode surface. Passivation of the electrode through adsorption of oxidation products was shown to severely limit the detection of OTA upon successive detection cycles. Comparison of various metallophthalocyanine modifiers showed an increase in sensitivity toward the detection of OTA at phthalocyanine complexes with metal based redox processes. However with the exception of NiPc and CoTCPc complexes, phthalocyanine modification was limited by the increase in deviation of current response and extent of fouling. NiPc modification showed an increase in sensitivity by two fold with fouling characteristics comparable to an unmodified electrode while low improvements in fouling was observed at CoTCPc modified electrodes with sensitivity in detection comparable to an unmodified electrode.Modification of the electrode with multi- and single walled carbon nanotubes produced a significant increase in sensitivity toward the detection of ochratoxin A. The electrocatalytic activity of nanotube modifiers was attributed to the increase in surface area and to the addition of oxygenated functional groups upon acid treatment as confirmed by Raman spectroscopy. Acid functionalization of the carbon nanotubes for a period of two hours produced the greatest increase in sensitivity obtaining a respective LOD of 0.09 μM and 0.03 μM for analysis of ochratoxin A at multi- and single walled carbon nanotube modified electrodes. Centrifugal purification of carbon nanotubes was deemed necessary to improve the electrocatalytic activity of the nanotube modifiers through the removal of carbonaceous impurities as visualized by atomic force microscopy. Furthermore, a crude lipase preparation, lipase A, was investigated as a potential biological recognition element for selective detection of ochratoxin A in complex media. Lipase A enabled the hydrolysis of ochratoxin A to the electroactive species ochratoxin α as confirmed by thin layer chromatography and voltammetric analysis. Additional isolation of a pure hydrolase from the lipase A preparation is required prior to utilization within a nanostructured biosensor platform capable of detecting ochratoxin A in complex media.
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Analysis for ochratoxin A by molecularly imprinted sold phase extraction and pulsed elution /Zhou, Simon Ningsun, January 1900 (has links)
Thesis (M. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 98-104). Also available in electronic format on the Internet.
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Development of polypyrrole encapsulated nanomaterials in a syringe needle for automated molecularly imprinted solid phase extraction of Ochratoxin A /Wei, Yun, January 1900 (has links)
Thesis (M.SC.) - Carleton University, 2007. / Includes bibliographical references (p. 85-93). Also available in electronic format on the Internet.
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