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master's thesis
Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida
Zagreb: University of Zagreb, Faculty of Chemical Engineering and Technology, 2015. urn:nbn:hr:149:415696
Gospić, Ema Antonia
University of Zagreb
Faculty of Chemical Engineering and Technology

Institutional repository: Repository of Faculty of Chemical Engineering and Technology University of Zagreb

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Gospić, E. A. (2015). Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida (Master's thesis). Zagreb: University of Zagreb, Faculty of Chemical Engineering and Technology. Retrieved from https://urn.nsk.hr/urn:nbn:hr:149:415696

Gospić, Ema Antonia. "Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida." Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, 2015. https://urn.nsk.hr/urn:nbn:hr:149:415696

Gospić, Ema Antonia. "Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida." Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, 2015. https://urn.nsk.hr/urn:nbn:hr:149:415696

Gospić, E. A. (2015). 'Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida', Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, accessed 25 November 2024, https://urn.nsk.hr/urn:nbn:hr:149:415696

Gospić EA. Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida [Master's thesis]. Zagreb: University of Zagreb, Faculty of Chemical Engineering and Technology; 2015 [cited 2024 November 25] Available at: https://urn.nsk.hr/urn:nbn:hr:149:415696

E. A. Gospić, "Elektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida", Master's thesis, University of Zagreb, Faculty of Chemical Engineering and Technology, Zagreb, 2015. Available at: https://urn.nsk.hr/urn:nbn:hr:149:415696

Metadata
TitleElektrokemijska detekcija antioksidansa na elektrodi od grafitne paste s nanočesticama titan dioksida
Title (english)Electrochemical investigation of antioxidants at TiO2 nanoparticles modified carbon paste electrode
AuthorEma Antonia Gospić
MentorSanja Martinez (mentor)
Committee memberSanja Martinez (predsjednik povjerenstva)
Committee memberMarijana Kraljić Roković (član povjerenstva)
Committee memberMartina Biošić (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Chemical Engineering and Technology
Zagreb
Defense date and country2015-09-21, Croatia
Scientific / art field,
discipline and subdiscipline		TECHNICAL SCIENCES
Chemical Engineering
Analysis, Synthesis and Management of Chemical Processes
Abstract
U ovom radu istražen je utjecaj modifikacije elektrode od grafitne paste nanočesticama titan dioksida u svrhu poboljšanja osjetljivosti i selektivnosti elektrode. Grafitna pasta modificirana je sa 15 odnosno 30% nanočestica TiO2, ali s obzirom da u preliminarnim istraživanjima povećanje udjela nanočestica nije dovelo do poboljšanja signala, daljnja istraživanja nastavljena su na elektrodi s 15% TiO2. Odziv modificirane elektrode ispitan je cikličkom voltametrijom u otopinama šest antioksidansa: askorbinske, mokraćne, galne, kumarinske, kavene i klorogenske kiseline. Elektroda je također osvijetljena UV lampom da bi se ispitao utjecaj fotokatalitičkog efekta nanočestica titan dioksida na njen odziv. Dobiveni rezultati uspoređeni su sa odzivom elektrode od čiste grafitne paste i pokazuju da se dodatkom nanočestica TiO2, već na sobnom osvjetljenju, a posebice pod UV lampom, oksidacijska struja povećava, a strujni vrhovi se pomiču prema nižim potencijalima. Budući da se oksidacijski strujni vrhovi svih ispitivanih kiselina nalaze na bliskim potencijalima, odziv modificirane elektrode ispitan je i u devet otopina njihovih mješavina. Najbolji odziv odnosno najbolje razdvajanje signala postignuto je u mješavinama s kumarinskom kiselinom, dok je najgore u otopinama s askorbinskom kiselinom. UV svjetlost ne poboljšava značajno odziv mješavina na modificiranoj elektrodi.
Abstract (english)
For the purposes of this study, carbon paste electrode was modified with TiO2 nanoparticles in order to enhance its sensitivity and selectivity. The paste was modified with 15 and 30% of nanoparticles, but since the larger amount of TiO2 didn't improve the given signal, further studies were conducted only with 15% TiO2 modified carbon paste electrode. The electrochemical behaviour of the modified electrode was investigated by cyclic voltammetry in water solutions of six antioxidants: ascorbic, uric, gallic, coumaric, caffeic an chlorogenic acid. The electrode was also illuminated with UV lamp to study photocatalytic effect of TiO2. Obtained results were compared to the results on the bare carbon paste electrode and they show that the presence of TiO2, especially under the UV illumination, improved the sensitivity by enhancing peak currents and shifting the oxidation potentials to lower values. Since all investigated acids have quite close oxidation potentials, cyclic voltammetry with modified electrode was performed in nine mixtures of the acids. Best response was obtained in mixtures with coumaric acid, while the response was worst in ascorbic acid mixtures. In almost all the cases, UV light didn't improve significantly signal of antioxidant mixtures.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:149:415696
Study programmeTitle: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry
Course: Advanced materials and technologies
Study programme type: university
Study level: graduate
Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
Type of resourceText
File originBorn digital
Access conditionsOpen access
Terms of useLicence In copyright icon
Created on2017-03-06 13:05:30