Optimiranje odziva pH osjetljivih fluorofora u optičkim senzorima za ione

master's thesis

• Title (english): Optimising response of pH sensitive fluorophores in ion-selective optical sensors
• Author: Nika Gazdek
• Mentor: Ivana Steinberg (mentor)
• Committee member: Ivana Steinberg (predsjednik povjerenstva)
• Committee member: Nataša Perin (član povjerenstva)
• Committee member: Petar Kassal (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2018-07-04, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry; Applied Chemistry

Abstract

Optički kemijski senzori u proteklih nekoliko godina okupiraju veliku pažnju znanstvenika zbog svoje jednostavnosti, brzine i preciznosti detekcije analita. Optički senzori temeljeni na ionoforima (engl. Ionophore Based Optical Sensors, IBOS) se sve više istražuju zbog širokih mogućnosti odabira funkcionalnih materijala te njihove odgovarajuće kombinacije kojom se postiže selektivnost za točno određeni ion. IBOS sadrže ionofor i fluorofor/kromofor kao indikator. Velik broj derivata iminokumarina, zbog svojstva gašenja ili pojačavanja intenziteta fluorescencije u prisutnosti analita, koriste se kao fluorescirajuće jedinice (fluorofori). Senzori u obliku filma pridodaju stabilnosti i čvrstoći takvog sustava. U ovom radu razvijen je film koji sadrži ionofor (valinomicin) te fluorofor (7-N,N-dietilamino-2-imino-3-(2-N-metilbenzimidazolil)kromen (IM-2)) imobilizirane u PVC, te služi kao ion-selektivna optoda (optički senzor) za kalijeve ione. Cilj rada je UV-vidljivom apsorpcijskom i fluorescencijskom spektrofotometrijom okarakterizirati film koji sadrži fluorofor IM-2 kao fluorescentnu jedinicu te ocijeniti njegovu moguću primjenu u optičkim senzorima za ione. U radu je određena osjetljivost, utjecaj pH, stabilnost i selektivnost senzora. Senzor pokazuje dobre analitičke parametre. Najosjetljiviji je kod pH 8 pri kojem detektira različite koncentracije kalija od 3,16*10^-4 mol/dm^-3 do 1 mol/dm^-3. Senzor pokazuje dugoročnu stabilnost te selektivnost za kalij uz prisutnost alkalijskih i zemnoalkalijskih iona dok trovalentni kationi ometaju rad senzora.

Abstract (english)

Optical chemical sensors have attracted much attention in the past few years for their simplicity, fast response and precision in analyte detection. Ionophore based optical sensors (IBOS) are being extensively researched for possibility of choosing and assembling the components for the purpose of better selectivity. Ionophore based optical sensors contain an ionophore and fluorophore/chromophore as an indicator. Large number of iminocoumarine derivatives are used as fluorophores, due to their ability of fluorescence quenching or fluorescence amplification upon reaction with the analyte. Immobilisation into films adds to the stability and firmness of sensor systems. This work represents the development of a film that contains ionophore (valinomycin) and fluorophore (7-N,N-diethylamino-2-imino-3-(2-N-methylbenzimidazolyl)chromen (IM-2)) immobilised in a PVC matrix, which functions as an ion-selective optode (optical sensor) for potassium ions. The purpose of this work was spectrophotometric (UV-visible absorption and fluorescence) characterisation of the film containing the fluorophore IM-2 as a fluorescent unit and to evaluate the possibility of usage in optical ion sensors. Sensor sensitivity, influence of pH, selectivity and stability were evaluated. Sensor shows good analytical parameters showing the highest sensitivity at pH 8 at which various potassium concentrations ranging from 3.16*10^-4 mol/dm^-3 to 1 mol/dm^-3 can be detected. Sensor shows great stability and potassium selectivity among alkali metals and alkaline earth metals whereas trivalent cations interfere with sensor’s functionality.

• Keywords: optički senzori; ionofor bazirani optički senzori; iminokumarini; fluorofor; fluorescencija
• Keywords (english): optical sensors; ionophore based optical sensors; iminocoumarine; fluorophore; fluorescence
• Language: croatian
• URN:NBN: urn:nbn:hr:149:009985
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Applied organic chemistry; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra primijenjene kemije (magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-05-08 10:09:26