doktorska disertacija
Eva Rajh (Author), Aleksandra Lobnik (Mentor), Mitja Kolar (Thesis defence commission member), Jernej Iskra (Thesis defence commission member), Ema Žagar (Thesis defence commission member), Marijan Kočevar (Co-mentor)

Abstract

V okviru te disertacije je predstavljena strukturna modifikacija indikatorja rodamina B in vpliv strukturne modifikacije na optične in senzorske lastnosti indikatorja. Rodamin B smo strukturno modificirali z etilendiaminom in preučili, kako je navidezno majhna strukturna sprememba, vplivala na lastnosti indikatorja. Sintetiziran indikator RhB-EDA je ob konstantni pH vrednosti pokazal visoko občutljivost in selektivnost za ione Ag$^+$ med vsemi testiranimi kovinskimi ioni (K$^+$, Mg$^{2+}$, Cu$^{2+}$, Ni$^{2+}$, Fe$^{2+}$, Pb$^{2+}$, Na$^+$, Mn$^{2+}$, Li$^+$, Al$^{3+}$, Co$^{2+}$, Hg$^{2+}$, Sr$^{2+}$, Ca$^{2+}$, Ag$^+$, Cd$^{2+}$ in Zn$^{2+}$), medtem ko izhodiščni indikator rodamin B kaže veliko manjšo občutljivost na ione Ag$^+$, a visoko občutljivost na Fe$^{2+}$ ione. Novi fluorescentni indikator RhB-EDA ima zmožnosti zaznavanja Ag$^+$ ionov do μM koncentracij z zniževanjem intenzitete fluorescence. Indikator RhB-EDA je pokazal dinamičen odziv na Ag$^+$ ione v območju 0,43 10$^{-3}$ – 10$^{-6}$ M z mejo zaznave 0,1 μM. Sistem zaznavanja novega indikatorja RhB-EDA je bil optimiziran glede na spektralne lastnosti, učinek pH in pufra, fotostabilnost, čas inkubacije, občutljivost in selektivnost. Ker so bile vse optične in senzorske lastnosti preizkušene v vodnem mediju, čeprav se številni drugi podobni senzorski sistemi zanašajo na raztopine organskih topil, je indikator RhB-EDA lahko dober kandidat za zaznavanje Ag$^+$ ionov v resničnih aplikacijah. V nadaljevanju smo z etilendiaminom modificirani indikator še dodatno modificirali z metilakrilatom in ponovno z etilendiaminom ter ponovno preverili optične in senzorske lastnosti. Sintetiziran indikator RhB-EDA-MA-EDA je pokazal zanimive optične lastnosti. Z modifikacijo se je po prvi kot po drugi strukturni modifikaciji spremenila valovna dolžina eksitacije in emisije, obenem pa smo z njo vplivali tudi na indikatorjev Stokesov premik. V okviru te disertacije smo uspeli oblikovati rodaminski derivat z nadpovprečno velikim Stokesovim premikom. S strukturno modifikacijo izhodiščnega indikatorja smo bistveno vplivali tudi na njegovo selektivnost. Med vsemi testiranimi kovinskimi ioni (K$^+$, Mg$^{2+}$, Cu$^{2+}$, Ni$^{2+}$, Fe$^{2+}$, Pb$^{2+}$, Na$^+$, Mn$^{2+}$, Li$^+$, Al$^{3+}$, Co$^{2+}$, Hg$^{2+}$, Sr$^{2+}$, Ca$^{2+}$, Ag$^+$, Cd$^{2+}$ in Zn$^{2+}$), je RhB-EDA-MA-EDA pokazal neselektivno občutljivost na Hg$^{2+}$, Fe$^{2+}$, Al$^{3+}$ in Zn$^{2+}$. Novi fluorescentni indikator RhB-EDA-MA-EDA je pri valovni dolžini eksitacije 274 nm pokazal dinamičen odziv na Al$^{3+}$ ione v območju 4 10$^{-3}$ – 4·10$^{-7}$ M z mejo zaznave 0,2 μM. Obenem pa je pri valovni dolžini eksitacije 393 nm pokazal tudi dinamičen odziv na Fe$^{2+}$ ione v območju 5 10$^{-4}$ – 6 10$^{-6}$ M z mejo zaznave 4 μM. Sistem zaznavanja novegaindikatorja RhB- EDA-MA-EDA je bil optimiziran glede na spektralne lastnosti, učinek pH in pufra, fotostabilnost, čas inkubacije in občutljivost. Glede na mejo zaznave in koncentracijsko območje indikatorja za zaznavanje Fe$^{2+}$ in Al$^{3+}$ ionov, bi bil indikator RhB- EDA-MA-EDA lahko primeren za realne meritve omenjenih ionov v okolju. V okviru te disertacije smo ugotovili, da so se optične in senzorske lastnosti indikatorja spremenile nepredvidljivo, povsem naključno glede na strukturno modifikacijo. Vsak korak modifikacije je na optične in senzorske lastnosti vplival drugače.

Keywords

optični indikatorji;rodamin B;strukturne modifikacije;dendrimeri;dendrimerne strukture;doktorske disertacije;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [E. Soršak]
UDC: 543:681.586.5(043.3)
COBISS: 195513603 Link will open in a new window
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Downloads: 4
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Other data

Secondary language: English
Secondary title: Modified Rhodamine B based optical sensor probes
Secondary abstract: In the present doctoral thesis, the structural modification of the rhodamine B indicator and the influence of synthetic procedures on the optical and sensor properties of the indicator is described. Rhodamine B was structurally modified with ethylene diamine and examined how a seemingly small structural change affected the properties of the indicator. The synthesized RhB-EDA fluorescent indicator shows interesting optical sensor properties, and high sensitivity and selectivity to Ag$^+$ ions among all the tested metal ions (K$^+$, Mg$^{2+}$, Cu$^{2+}$, Ni$^{2+}$, Fe$^{2+}$, Pb$^{2+}$, Na$^+$, Mn$^{2+}$, Li$^+$, Al$^{3+}$, Co$^{2+}$, Hg$^{2+}$, Sr$^{2+}$, Ca$^{2+}$, Ag$^+$, Cd$^{2+}$ in Zn$^{2+}$), while the well-known Rhodamine B (RhB) fluorescent probe shows much less sensitivity to Ag$^+$ ions, but high sensitivity to Fe$^{2+}$ ions. The new RhB-EDA fluorescent indicator has has the ability to detect Ag$^+$ ions up to μM concentrations by using the fluorescence quenching approach. The probe displayed a dynamic response to Ag$^+$ in the range of 0.43 10$^{-3}$ – 10$^{-6}$ M with a detection limit of 0.1 μM. The sensing system of an RhB-EDA novel fluorescent probe was optimised according to the spectral properties, effect of pH and buffer, photostability, incubation time, sensitivity, and selectivity. Since all the spectral and sensing properties were tested in green aqueous media, although many other similar sensor systems rely on organic solvent solutions, the RhB-EDA sensing probe may be a good candidate for measuring Ag$^+$ ions in real-life applications. Subsequently, the ethylenediamine-modified indicator was further modified with methylacrylate and again with ethylenediamine, and the optical and sensor properties were checked again. The synthesized RhB-EDA-MA-EDA indicator showed interesting optical properties. The modification changed the wavelength of excitation and emission after the first and second structural modification, and at the same time we also influenced the Stokes shift of the indicators. In the framework of this dissertation, we managed to form a rhodamine derivative with an above-average Stokes shift. The structural modification of the baseline indicator also significantly affected its selectivity. Among all the metal ions tested (K$^+$, Mg$^{2+}$, Cu$^{2+}$, Ni$^{2+}$, Fe$^{2+}$, Pb$^{2+}$, Na$^+$, Mn$^{2+}$, Li$^+$, Al$^{3+}$, Co$^{2+}$, Hg$^{2+}$, Sr$^{2+}$, Ca$^{2+}$, Ag$^+$, Cd$^{2+}$ in Zn$^{2+}$), RhB-EDA-MA-EDA showed non-selective sensitivity to Hg$^{2+}$, Fe$^{2+}$, Al$^{3+}$ and Zn$^{2+}$. The new fluorescent indicator RhB-EDA-MA-EDA showed a dynamic response to Al$^{3+}$ ions in the range of 4 10$^{-3}$ – 4·10$^{-7}$ M at an excitation wavelength of 274 nm with a detection limit of 0.2 μM. At the same time, at an excitation wavelength of 393 nm, it also showed a dynamic response to Fe$^{2+}$ ions in the range of 5 10$^{-4}$ – 6 10$^{-6}$ M with a detection limit of 4 μM. The detection system of the new RhB- EDA-MA-EDA indicator has been optimized according to spectral properties, pH and buffer effect, photostability, incubation time and sensitivity. Given the detection limit and concentration range of the indicator forthe detection of Fe$^{2+}$ and Al$^{3+}$ ions, the indicator RhB-EDA-MA-EDA could be suitable for measuring these ions in the environment. In the context of this dissertation, we found that the optical and sensor properties of the indicator changed in an unpredictable, completely random way depending on the structural modification. Each modification step had a different impact on the optical and sensor properties.
Secondary keywords: rhodamine B;optical indicator;structural modification;optical sensors;Optični senzorji;Optične lastnosti;Fluorescenca;Univerzitetna in visokošolska dela;
Type (COBISS): Doctoral dissertation
Study programme: 1000381
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo
Pages: XVII, 124 f.
ID: 23668355