Primjena grafena u dizajnu elektrokemijskog senzora za analizu kvetiapina

master's thesis

• Title (english): Graphen application in design of electrochemical sensor for quetiapine analysis
• Author: Ivana Ćurak
• Mentor: Biljana Nigović (mentor)
• Committee member: Branka Zorc
• Committee member: Biljana Nigović
• Committee member: Miranda Sertić
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of pharmaceutical analysis); Zagreb
• Defense date and country: 2015-05-15, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Kvetiapin je dibenzotiazepinski antipsihotik druge generacije. Danas je jedan od najčešće propisivanih lijekova za liječenje shizofrenije.
U ovom radu, ispitan je utjecaj modifikacije površine elektrode od staklastog ugljika s grafenom u 0.1%-tnoj otopini Nafiona na voltametrijski odgovor lijeka. Svrha ispitivanja bila je odrediti može li modifikacija elektrode grafenom poslužiti za razvoj nove analitičke metode za određivanje kvetiapina.
Mjerenja na modificiranoj elektrodi pokazala su da je strujni vrh oksidacije kvetiapina pri vrijednosti potencijala od 1.06 V veći i izraženiji u odnosu na nemodificiranu elektrodu. Grafen povećava strujni vrh ispitivanog analita jer značajno povećava površinu te olakšava oksidaciju lijeka (prijenos elektrona). Nafion kao polimer pridonosi boljem vezanju grafena na površinu elektrode. Također, Nafion kao kationsko izmjenjivačka smola omogućava adsorpciju pozitivno nabijenih molekula lijeka na površinu elektrode.
Snimljeni su ciklički voltamogrami otopine lijeka u Britton-Robinsonovom puferu različitih pH vrijednosti. Rezultati su pokazali da se porastom pH vrijednosti potencijal oksidacije pomiče prema manje pozitivnim vrijednostima, što dokazuje da prijenos protona sudjeluje u oksidaciji kvetiapina. Također, pH vrijednost 4 odabrana je kao optimalna za daljnja mjerenja. Kako bi se dobio što osjetljiviji voltametrijski odgovor za analitička mjerenja praćena je promjena struje vrha zabilježena na modificiranoj elektrodi mijenjanjem instrumentalnih parametara diferencijalne pulsne voltametrije.

Abstract (english)

Quetiapine is a dibenzothiazepine antipsyhotic medicine of second-generation. Today, it is one of the most prescribed drugs for treating schizophrenia.
In this thesis, the influence of surface modification of glassy carbon electrode with graphene in 0.1% Nafion solution on quetiapine voltammetric response was investigated. The purpose of this research was to define can the modification of electrode with graphene lead to development of a new electroanalytical method for the determination of quetiapine.
Measurements on modified electrode have shown that the peak current observed at the potential of 1.06 V was higher and well-defined compared to the peak current obtained at unmodified electrode. Graphene enhances the peak current of examined medicine because it significantly increases electrode surface area and facilitates the electron transfer reaction. Nafion as polymer contributes to better binding of graphene on the electrode surface. Also, Nafion as cation-exchange polymer provides the adsorption of positively charged drug molecules on the electrode surface.
Cyclic voltammograms of quetiapine in Britton-Robinson buffer solutions at various pH values were recorded. The results have shown that the oxidation peak potentials were shifted to the less positive values by increasing the pH, suggesting that the proton transfer is involved in the oxidation reaction of quetiapine. Also, the pH value of 4 was selected as optimal for further measurements. To obtain a much more sensitive voltammetric response for analytical studies, the variation of the peak current recorded at modified electrode was monitored while changing instrumental differential pulse voltammetric parameters.

• Keywords: kvetiapin; grafenom modificirana elektroda; ciklička voltametrija; diferencijalna pulsna voltametrija
• Keywords (english): quetiapine; graphene modified electrode; cyclic voltammetry; differential pulse voltammetry
• Language: croatian
• URN:NBN: urn:nbn:hr:163:803543
• Study programme: Title: Pharmacy; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra farmacije (magistar/magistra farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2015-12-17 14:45:06