Primjena fluorescentnih derivata benzimidazola u funkcionalnim materijalima

master's thesis

• Title (english): Application of fluorescent benzimidazole derivatives in functional materials
• Author: Vedran Vučić
• Mentor: Ivana Steinberg (mentor)
• Committee member: Ivana Steinberg (predsjednik povjerenstva)
• Committee member: Ema Horak (član povjerenstva)
• Committee member: Nataša Perin (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2017-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Applied Chemistry

Abstract

Cilj ovog rada je razvoj novih funkcionalnih materijala temeljenih na derivatima benzimidazola. Pripravljen je novi ireverzibilni kemijski optički senzor (optoda) - kemodozimetar za detekciju žive, čiji se mehanizam rada temelji na fluorescentnom odgovoru derivata benzimidazola 2-N-piperidinilbenzimidazol[1,2-a]kinolin-6-karbonitrila imobiliziranog u plastificiranu polimernu matricu. Funkcija optode se zasniva na stvaranju ionskih parova odabranog benzimidazolnog derivata i lipofilne anionske soli tetraklorfenil borata. Benzimidazolni derivat je u ovom slučaju fluorofor – odgovoran za nastanak analitičkog signala, a lipofilni anion (boratna sol) osjetilni dio optode koji prepoznaje ione žive u mjerenom uzorku (receptor). Boratna sol se u prisutnosti žive raspada, čime se raspada i ionski par Florofor+Receptor-, te se istovremeno benzimidazolni fluorofor deprotonira radi uravnoteženja naboja u polimernoj membrani. Deprotoniranjem fluorofor mijenja svoja fotofizčka svojstva, odnosno intenzitet fluorescencije raste (engl. turn-on senzor). Korištenjem tehnike nanošenja filma brzim rotiranjem (engl. Spin coating) i imobilizacijom fluorofora i boratne soli u plastificiranu PVC matricu, pripravljen je tanki film na prozirnom nosaču (optoda). U radu je istražen utjecaj pH na fluorescenciju te optimalno pH područje za najbolji odziv optode, istražen je mehanizam senzorskog djelovanja, raspon koncentracija u kojem se optoda može koristiti za detekciju žive u otopini, vrijeme odziva, stabilnost optode u puferu i selektivnost prema ionima žive. Optoda je karakterizirana UV-vidljivom apsorpcijskom i fluorescencijskom spektrofotometrijom. Uspješno je pripravljen kemijski optički senzor za detekciju žive u rasponu koncentracija od c = 5*10^-4 M do c = 1*10^-6 M. Prilikom detektiranja žive u senzoru se događaju ireverzibilne kemijske promjene što ga definira kao kemodozimetar. Ispitane su interferencije drugih metala, gdje je najveće odstupanje analitičkog od referentnog signala iznosilo 12%. Senzor je stabilan unutar djelovanja od 15 minuta.

Abstract (english)

The aim of this work is to develop novel functional materials based on benzimidazole derivates. A new irreversible chemical optical sensor (optode) - a chemodosimeter for mercury detection based on the fluorescence response of benzimidazole, 2-N-piperidinylbenzimidazole[1,2-a]quinoline-6-carbonitrile immobilised in the polymer matrix was prepared. The sensing mechanism is based on the formation of ionic pair of the selected benzimidazole derivative and the lipophilic anionic salt, tetrachlorophenyl borate. The benzimidazole derivate is fluorophore responsible for the formation of the analytical signal, whilst lipophilic anion (borate salt) is the sensing part of the optode, responsible for the detection of mercury ions in the measured sample (receptor for mercury ions). Borate salt in the presence of mercury ions is decomposed, and at the same time, the ionic pair of Fluorophfore+Receptor- is disintegrated after which the benzimidazole fluorophore deprotonates for balancing charge in the polymer membrane. By deprotonating, the fluorophore changes its photophysical properties, or the fluorescence intensity increases (turn-on senor). Thin film on a transparent carrier, optode, was prepared by spin coating technique, immobilising fluorophore and anionic borate salt in a plasticized PVC matrix. The influence of pH and the optimum pH range for the best fluorescence response of the optode was investigated. The mechanism of sensing activity, the range of concentrations in which the optode can be used for mercury detection in the solution, the response time, the stability in the buffer and the selectivity of mercury was described. The optode is characterized by UV-visible absorption and fluorescence spectrophotometry. A chemical optical sensor for mercury detection has been successfully developed in the concentration range of c = 5*10^-4 M to c = 1*10^-6 M. During the detection of mercury, in the sensor, there are irreversible chemical changes that define it as a chemodosimeter. Interferences with other metals were investigated where the greatest deviation of the analytical signal from the reference signal was about 12%. Sensor showed good stability within a 15-minute sensory activity.

• Keywords: benzimidazol; funkcionalni materijali; kemijski optički senzori; kemodozimetar; živa; fluorescencija
• Keywords (english): benzimidazole; functional materials; chemical optical sensors; chemodosimeter; mercury; fluorescence
• Language: croatian
• URN:NBN: urn:nbn:hr:149:055729
• Study programme: Title: Environmental Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka ekoinženjerstva (magistar/magistra inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-04-21 13:00:00