Modification of boron doped diamond electrode by electrochemical oxidation of p-aminobenzoic acid

This bachelor's thesis deals with the modification of a boron-doped diamond electrode (BDDE) by the electrochemical oxidation of p-aminobenzoic acid. Subsequently, the stability of the modified electrode was investigated by a study of various parameters. The modification of the electrode was performed using cyclic voltammetry (CV) in LiClO4 electrolyte. The success of the modification and its subsequent stability was investigated by the CV method in electrolyte KCl in the presence of the redox system [Fe(CN)6]4-/3- . Stability was tested in terms of ultrasonic cleaning in isopropanol and anodic cleaning in 0.5 mol l-1 H2SO4. It was found that the modification of the surface cannot be completely removed by ultrasonic cleaning in isopropanol, in contrast, pulses of period 2 seconds with a high positive potential are enough to completely remove the modification. Optimal conditions for surface stability were determined. The ideal number of cycles for surface modification was set at 5 cycles. The use of different electrolytes during modification (KClO4 and LiClO4) determined that in the case of modification in the KClO4 electrolyte, it is possible to measure in the range of the potential window from -400 to +1600 mV and in the case of LiClO4 in the range of -400 to +1500 mV without breaking the modified...Tato bakalářská práce se zabývá modifikací borem dopované diamantové elektrody (BDDE) elektrochemickou oxidací kyseliny p-aminobenzoové. Následně byla zkoumána stabilita modifikované elektrody vlivem aplikace různých parametrů. Modifikace elektrody byla provedena metodou cyklické voltametrie (CV) v elektrolytu LiClO4. Úspěšnost modifikace a její následná stabilita byla zkoumána též metodou CV v elektrolytu KCl v přítomnosti redoxního systému [Fe(CN)6]4-/3- . Stabilita byla testována z hlediska čištění v isopropanolu ultrazvukem a anodického čištění v 0,5 mol l-1 H2SO4. Bylo zjištěno, že modifikace povrchu čištěním v isopropanolu ultrazvukem zcela odstranit nelze, naopak při anodickém čištění stačí pro úplně odstranění modifikace pouhý 2s pulz o vysokém kladném potenciálu. Byly stanoveny optimální podmínky pro stabilitu modifikace povrchu. Ideální počet cyklů při modifikaci povrchu byl stanoven na 5 cyklů. Použitím různých elektrolytů při modifikaci (KClO4 a LiClO4) bylo určeno, že v případě modifikace v elektrolytu KClO4 je možné měřit v rozsahu potenciálového okna od -400 do +1600 mV a v případě LiClO4 v rozsahu od -400 do +1500 mV bez porušení modifikované vrstvy. Z hlediska stárnutí elektrody se objevila větší stabilita u modifikace v přítomnosti LiClO4. Klíčová slova: Borem dopovaná diamantová...Department of Analytical ChemistryKatedra analytické chemieFaculty of SciencePřírodovědecká fakult

Modification of boron doped diamond electrode by electrochemical oxidation of p-aminobenzoic acid

This bachelor's thesis deals with the modification of a boron-doped diamond electrode (BDDE) by the electrochemical oxidation of p-aminobenzoic acid. Subsequently, the stability of the modified electrode was investigated by a study of various parameters. The modification of the electrode was performed using cyclic voltammetry (CV) in LiClO4 electrolyte. The success of the modification and its subsequent stability was investigated by the CV method in electrolyte KCl in the presence of the redox system [Fe(CN)6]4-/3- . Stability was tested in terms of ultrasonic cleaning in isopropanol and anodic cleaning in 0.5 mol l-1 H2SO4. It was found that the modification of the surface cannot be completely removed by ultrasonic cleaning in isopropanol, in contrast, pulses of period 2 seconds with a high positive potential are enough to completely remove the modification. Optimal conditions for surface stability were determined. The ideal number of cycles for surface modification was set at 5 cycles. The use of different electrolytes during modification (KClO4 and LiClO4) determined that in the case of modification in the KClO4 electrolyte, it is possible to measure in the range of the potential window from -400 to +1600 mV and in the case of LiClO4 in the range of -400 to +1500 mV without breaking the modified..