Razvoj in uporaba elektrokemijskih senzorjev na osnovi modificiranih sitotiskanih elektrod za določanje nanoplastike

Martinc, Nina (author), Marolt, Gregor (mentor)

Plastika je dandanes zaradi svoje vsestranskosti, prilagodljivosti, cenovne ugodnosti in trpežnosti pogosto uporabljen material na različnih področjih. Zaradi množične proizvodnje plastičnih materialov je v okolju prisotna kot količinsko problematičen odpadek. Med večje probleme onesnaženja spada fragmentacija plastike na manjše delce, kar vodi do nastanka mikroplastike (MP) in nanoplastike (NP). Ta proces je problematičen, saj je delce manjših velikosti bistveno težje odstranjevati iz okolja. Problematiko predstavlja tudi vstopanje manjših delcev v telesa ljudi in živali, njihov vpliv na katere še ni popolnoma znan, postaja pa vse bolj pomembno vprašanje. Cilj magistrske naloge je razvoj elektrokemijskega senzorja, ki deluje na osnovi ciklične voltametrije. Osnova senzorja je komercialni sitotiskani trielektrodni sistem z zlato delovno elektrodo, srebrno kvazi-referenčno elektrodo ter zlato protielektrodo. Pred uporabo na elektrodah izvedemo modifikacijo, v prvi fazi modifikacije sem izvedla elektrodepozicijo tankega sloja mezoporozne silike, na katerega sem nato preko epoksisilana vezala različne aminokisline, ki omogočajo vezavno mesto za delce MP in NP. Delovanje tako modificiranega senzorja, sem testirala v standardni raztopini polistirena pri različnih vrednostih pH, napetostih, ob tem pa sem optimizirala tudi pogoje elektrodepozicije mezoporozne silike (čas in napetost). Modificirane elektrode sem testirala tudi v suspenziji realnega vzorca (delci MP in NP, v suspenziji delcev iz avtomobilskih gum). Cilj raziskav je potrditi vezavo delcev na modificirano elektrodo in dobljen elektrokemijski odziv primerjati z izmerjenim številom delcev. V ta namen sem poleg ciklične voltametrije vzporedno izvedla analizo z uporabo instrumenta na osnovi t.i. optifluidične indukcijske sile (angl. OptoFluidic Force Induction), ki omogoča karakterizacijo mikro- in nanodelcev, vključno s štetjem in določevanjem porazdelitve v velikostnem redu med 100 in 3000 nm. Da bi preverila posamično stopnjo modifikacije in potrdila sledečo adsorpcijo standarda polistirena, sem površino delovne elektrode analizirala z Ramansko spektroskopijo. Dobljeni rezultati so potrdili učinkovitost senzorja, kar kaže dober potencial za nadaljnji razvoj analiznih metod za detekcijo mikroplastike, ter in-situ uporabo

• Language: Slovenian
• Keywords: mikroplastika, nanoplastika, sitotiskana elektroda, modifikacija elektrode, kvantitativna analiza, Ramanska spektroskopija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-164316
• COBISS.SI-ID: 218953475
• Publication date in RUL: 22.10.2024

MARTINC, Nina, 2024, Razvoj in uporaba elektrokemijskih senzorjev na osnovi modificiranih sitotiskanih elektrod za določanje nanoplastike [online]. Master’s thesis. [Accessed 7 April 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=164316

Secondary language

• Language: English
• Title: Development and application of electrochemical sensors based on the modified screen-printed electrodes for the determination of nanoplastics

Abstract

Plastics are frequently used in various fields today due to their versatility, adaptability, cost-effectiveness, and durability. However, the mass production of plastic materials has resulted in plastic waste becoming a significant environmental issue. One of the major problems associated with plastic pollution is the fragmentation of plastic into smaller particles, leading to the formation of microplastics (MP) and nanoplastics (NP). This process is particularly problematic as smaller particles are considerably more challenging to be removed from the environment. Furthermore, the entry of these smaller particles into the bodies of humans and animals presents another issue; although their impact is not yet fully understood, it is becoming an increasingly important concern. The aim of this master's thesis is to develop an electrochemical sensor based on cyclic voltammetry. The sensor is built upon a commercial screen-printed three-electrode system comprising a gold working electrode, a silver quasi-reference electrode, and a gold counter electrode. Prior to use, the electrodes undergo a modification process. In the initial phase of this process, I performed electrodeposition of mesoporous silica thin film, onto which various amino acids were subsequently bound via epoxysilane. These amino acids provide binding sites for MP and NP particles. The performance of the modified sensor was tested in a standard polystyrene solution under varying pH levels and voltages. The conditions of mesoporous silica electrodeposition (time and voltage) were also optimized. Additionally, I tested the modified electrodes in a suspension of real samples (MP and NP aqueous suspension prepared from automobile tyres). The research aims to confirm the binding of particles to the modified electrode and to compare the resulting electrochemical response with the measured number of particles. To achieve this, alongside cyclic voltammetry, I conducted a quantitative analysis using the instrument based on optofluidic force induction, which enables the characterisation of micro- and nanoparticles, including counting and size distribution determination within the range of 100 to 3000 nm. To verify each modification stage and confirm the subsequent adsorption of the polystyrene standard, I analysed the surface of the working electrode using Raman spectroscopy. The results confirmed the sensor's effectiveness, indicating strong potential for further development of analytical methods for microplastic detection and in-situ application

• Keywords: microplastics, nanoplastics, screen-printed electrode, electrode modification, quantitative analysis, Raman spectroscopy.