Določanje elekroforetske mobilnosti fulerenheksamalonatnega iona s kapilarno elektroforezo

Kastelic, Anamarija (avtor), Cerar, Janez (mentor)

Kapilarna elektroforeza (angl. capillary electrophoresis) je analizna separacijska tehnika, katere prednost pred drugimi separacijskimi tehnikami je, da za analizo zahteva manjšo količino vzorcev in topil kot nekatere druge separacijske tehnike. Separacija poteka v električnem polju znotraj kapilare, napolnjene s pufrsko raztopino. Osnovni princip ločbe temelji na klasični elektroforezi in elektroosmotskem toku. S pojmom elektroforeza označujemo migracijo ionov pod vplivom električnega polja, medtem ko z izrazom elektroosmotski tok poimenujemo gibanje celotne raztopine elektrolita v kapilari proti katodi zaradi delno deprotoniranih silanolnih skupin na steni kapilare in prebitka kationov v pufru. Z elektroforezo ločimo delce z različnimi naboji, saj slednji znatno vplivajo na elektroforetske mobilnosti delcev, kot tudi delce z enakimi naboji, če so različnih velikosti ali oblik. V svojem delu sem želela z metodo kapilarne elektroforeze določiti elektroforetsko mobilnost fulerenheksamalonatnega iona, ki nastane pri ionizaciji fulerenheksamalonske kisline Th-C66(COOH)12. Elektroforetsko mobilnost sem izračunala iz izmerjenih migracijskih časov vzorca in acetona, električne napetosti na kapilari in dolžine kapilare. Ker je fulerenheksamalonska kislina občutljiva na delno dekarboksilacijo, smo na posnetih elektroferogramih opazili dva vrhova: prvi izvira iz nedegradirane kisline Th-C66(COOH)12, drugi pa je najverjetneje posledica prisotnosti enkrat dekarboksilirane fulerenheksamalonske kisline, C66H(COOH)11. Spreminjala sem pogoje ločbe, raztopino vzorca nakisala in jo segrevala pri višji temperaturi ter s tem pospešila delno dekarboksilacijo. Namerna degradacija vzorca se je odrazila tudi na elektroferogramih: pojavilo se je več novih vrhov, ki so bili posledica degradacije spojine, ko je iz molekule izstopila več kot le ena molekula CO2. V svoji diplomski nalogi sem med drugim tudi želela ugotoviti, kolikšna je ponovljivost izvedenih meritev elektroforetskih mobilnosti, kako na elektroforetsko mobilnost vplivata koncentracija pufra in napetost na kapilari, kakšna je učinkovitost ločbe, resolucija ter hidrodinamski polmer fulerenheksamalonatnega iona.

• Jezik: Slovenski jezik
• Ključne besede: kapilarna elektroforeza, elektroforetska mobilnost, fulerenheksamalonska kislina (FHMA), fulerenheksamalonatni ion
• Vrsta gradiva: Diplomsko delo/naloga
• Tipologija: 2.11 - Diplomsko delo
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Leto izida: 2020
• PID: 20.500.12556/RUL-119539
• COBISS.SI-ID: 29838083
• Datum objave v RUL: 09.09.2020

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Determination of electrophoretic mobility of fullerenehexamalonate ion using capillary electrophoresis

Izvleček

Capillary electrophoresis is an analytic separation technique, of which advantage over other separation techniques is that it requires smaller quantities of samples and solvents, when compared with some other separation techniques. Separation occurs under the influence of an electric field inside the capillary, filled with a buffer solution. The basic separation principle is based on classical electrophoresis and the electroosmotic flow. With the phrase electrophoresis we define the migration of ions under the influence of the electric field, meanwhile the term electroosmotic flow defines the movement of an entire electrolyte solution towards the cathode due to partially deprotonated silanol groups on the capillary wall and the consequent excess of cations in the buffer solution. Using electrophoresis, we can separate particles carrying different charges, as they significantly affect electrophoretic mobilities of them, and we can also separate particles of the same charge if they differ in size or shape. In this work, I wanted to determine the electrophoretic mobility of the fullerenehexamalonate ion with the use of capillary electrophoresis, which can be accomplished through complete ionization of fullerenehexamalonic acid Th-C66(COOH)12. I have calculated its electrophoretic mobility from the measured migration times for the analysed ion and acetone, applied voltage on the capillary, and the length of the capillary. Because fullerenehexamalonic acid is sensitive to partial decarboxylation, two peaks were observed in recorded electropherograms: the first peak belonged to non-degraded acid Th-C66(COOH)12, and the second one probably occurred due to the presence of once decarboxylated fullerenehexamalonic acid, C66H(COOH)11. I varied the conditions of separation, I acidified the sample and heated it to higher temperatures, in order to provoke its accelerated partial decarboxylation. This purposeful decarboxylation also reflected in the electropherograms: several new peaks were observed due to degradation of the compound when more than one CO2 molecule was released from the original molecule. I also wanted to determine the repeatability of our measurements of electrophoretic mobilities, how electrophoretic mobility is affected by the buffer concentration and voltage on the capillary, the separation efficiency, resolution and the hydrodynamic radius of the fullerenehexamalonate ion.

• Ključne besede: capillary electrophoresis, electrophoretic mobility, fullerenehexamalonic acid (FHMA), fullerenehexamalonate ion