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
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