| Abstract [eng] |
This dissertation investigates graphite intercalation compounds (GIC) with sulphuric acid, prepared with different oxidising agents, in the presence and absence of P2O5 as a water-binding agent, and using graphite with different size grains (<50 μm, ≥149 – ≤840 μm, 2000 μm). Structural analysis revealed that the use of K2S2O8 and (NH4)2S2O8 oxidisers results in a much lower concentration of defects compared to the use of CrO3. Also, P2O5 has a positive effect on the formation of the highly intercalated GIC. Additionally, GICs synthesised from different graphite grains were thermally treated to obtain exfoliated graphite and further modified with conductive polymers. Characterisation of the resulting exfoliated graphite-polypyrrole (GPPy) and exfoliated graphite-polythiocianogen (EG(SCN)n) composites showed that simple mechanochemical modification enabled nitrogen and sulphur incorporation into the graphitic structure. Furthermore, it was demonstrated that the obtained composites are suitable electrode materials for the electrochemical detection of neurotransmitters. The GPPy-based sensor achieved a sensitivity of 2468 µA mM⁻1 cm⁻2 with a LOD value of 34 nM for dopamine, while the EG(SCN)n-based sensor demonstrated a LOD value of 59.5 nM and a sensitivity of 1893 µA mM⁻1 cm⁻2 for serotonin. These results revealed the potential application of the prepared composites for the construction of highly sensitive metal- and enzyme-free sensors for neurotransmitter detection. |
