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Zaradi naraščanja proizvodnje, uporabe in odlaganja plastike se v okolju s časom veča tudi količina mikroplastike, ki nastane s fragmentacijo večjih plastičnih izdelkov. Zaradi majhne velikosti mikroplastike predstavlja njen monitoring zelo velik izziv, to težavo pa lahko rešimo z ustreznim senzorjem, ki je sposoben zaznavati majhne delce. Cilj magistrskega dela je bil razvoj zanesljivega senzorja za detekcijo mikroplastike, ki deluje na osnovi voltametrije. Osnovo senzorja sestavlja zlata elektroda, ki je lahko klasična disk elektroda ali sito-tiskana elektroda, ali klasična disk elektroda iz steklastega ogljika. Delovna površina elektrode je bila modificirana s tanko plastjo mezoporozne silike oziroma s plastjo silike, na katero je bila vezana še izbrana aminokislina - prolin. Posamezno stopnjo modifikacije in sledečo adsorpcijo mikroplastike smo preverjali z merjenjem ciklovoltametričnega odziva elektrod v ekvimolarni raztopini [Fe(CN)6]3-/[Fe(CN)6]4-, prekritost površine delovne elektrode z nanosom plasti silike pa smo preverili tudi z vrstičnim elektronskim mikroskopom. Delovanje tako oblikovanih senzorjev smo testirali na mikroplastiki, pripravljeni iz avtomobilskih gum, ter polietilenski mikroplastiki, pridobljeni iz kozmetičnih izdelkov, pri različnih pH vrednostih, časih vzorčenja, volumnih raztopine in časih elektrodepozicije. Rezultati dela so potrdili učinkovitost in zanesljivost senzorja za zaznavanje mikroplastike iz avtomobilskih gum na podlagi zlate delovne elektrode, pri čemer se je površina, modificirana s tankim slojem mezoporozne silike in prolinom, izkazala za najbolj učinkovito. Pripravljen senzor za detekcijo mikroplastike kaže velik potencial za nadaljnji razvoj aplikacij za detekcijo in monitoring mikroplastike ter in situ uporabo. As the production, use and disposal of plastics increases, the amount of microplastics in the environment, which are formed by the fragmentation of larger plastic products, is also increasing over time. The small size of microplastics makes their monitoring very challenging, but this problem can be solved with a suitable sensor capable of detecting small particles. The aim of the masters’ thesis was to develop a reliable sensor for the detection of microplastics based on voltammetry. The sensor base consists of a gold electrode, which can be a disk electrode, a screen-printed electrode, or a glassy carbon disk electrode. The working surface of the electrode was modified with a thin layer of mesoporous silica, or a layer of silica to which a selected amino acid, proline, was bonded. The individual modification step and the subsequent adsorption of microplastics were verified by measuring the cyclovoltammetric response of the electrodes in an equimolar solution of [Fe(CN)6]3-/[Fe(CN)6]4-, and the coverage of the working electrode surface by the silica layer was also verified a scanning electron microscope. The performance of the designed sensors was tested on microplastics prepared from car tyres and on polyethylene microplastics obtained from cosmetic products at different pH values, sampling times, solution volumes and electrodeposition times. The results of the work confirmed the performance and reliability of the sensor for the detection of car tyre microplastics based on a gold working electrode, with the surface modified with a thin layer of mesoporous silicas and proline proving to be the most effective. The sensor for detection of microplastics shows great potential for further development of microplastics detection, monitoring and in situ applications. |
