Electronic Theses and Dissertation

ABSTRAK



Glutation (GSH) merupakan senyawa tiol intraselular utama yang berpengaruh terhadap banyak proses biologis. Perubahan konsentrasi GSH dalam tubuh secara biologis dapat menyebabkan berbagai penyakit. Elektroda emas termodifikasi ferosen telah difabrikasi dalam penelitian ini untuk mendeteksi GSH melalui proses elektrokatalitik. Immobilisasi self-assembly monolayer (SAM) menggunakan asam 3-merkaptopropionik (3-MPA) yang mengandung gugus karboksilat digunakan sebagai linker antara aminoferosen (Fc-NH2) dan permukaan elektroda. Proses aktivasi gugus karboksilat dilakukan menggunakan senyawa 1-ethyl-3-(3-dimethyl amino propyl) carbodiimide (EDC) / n-hydroxy succinimide (NHS). Teknik siklik voltametri (CV) dan surface-enhance infrared absorption spectroscopy (SEIRAS) digunakan untuk mengkarakterisasi modifikasi permukaan elektroda. Kinerja elektroda emas termodifikasi ferosen sebagai sensor terhadap oksidasi elektrokatalitik GSH di dalam larutan buffer kemudian dievaluasi. Berdasarkan hasil square wave voltammetry (SWV), arus oksidasi elektrokatalitik GSH pada permukaan elektroda termodifikasi secara linier bergantung pada konsentrasi GSH, selama rentang konsentrasi antara 0,2 - 1 mM, dengan nilai R2 0,9906. Sensor hasil fabrikasi tersebut diusulkan untuk kajian lebih lanjut terhadap kesesuaian penggabungan Fc-NH2 menjadi elektroda emas termodifikasi ferosen dan deteksi GSH di dalam sampel klinis.

Kata kunci: ferosen, elektroda emas, glutation, elektrokatalitik, siklik voltametri, square wave voltammetry

ABSTRACT



Glutathione (GSH) is a major intracellular thiol compound that involved in many biological processes and the changes of GSH concentration in biological bodies may lead to diseases. Ferrocene-modified gold electrode was fabricated in this research to detect GSH via electrocatalytic process. Self-assembly monolayer (SAM) immobilization using 3-mercaptopropionic acid (3-MPA) which contains a carboxylate group was used to act as a linker of aminoferrocene (Fc-NH2) and electrode surface. The carboxylate group activation process was carried out using 1-ethyl-3-(3-dimethyl amino propyl) carbodiimide (EDC) / n-hydroxy succinimide (NHS) solution. Cyclic voltammetry (CV) and surface-enhance infra-red absorption spectroscopy (SEIRAS) techniques were used to characterize the electrode surface modification. Performances of ferrocene-modified gold electrode as a sensor for the electrocatalytic oxidation toward GSH in buffer aqueous solution were then evaluated. Using square wave voltammetry (SWV) technique, the electrocatalytic oxidation peak current of GSH at the surface of this modified electrode was linearly dependent on the GSH concentration, over the concentration range between 0.2 mM and 1 mM, with R2 value was 0.9906. The fabricated sensor was proposed for further study to the suitability of incorporation of Fc-NH2 into ferrocene-modified gold electrode and detection of GSH in clinical samples.

Keywords: ferrocene, gold electrode, glutathione, electrocatalysis, cyclic voltammetry, square wave voltammetry

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