Poli(tiyonin) Destekli Paladyum Nanopartikülleri İle H2O2 Tayini

Abstract

Önerilen tez çalışmasının amacı biyolojik sistemlerde oldukça önemli bir molekül olan hidrojen peroksit (H2O2) tayini için basit, düşük maliyetli ve hızlı bir amperometrik sensör geliştirilmesidir. Hazırlanan sensör için çalışma elektrodu olarak iletken bir redoks polimeri olan poli(tiyonin) (PTH) ve palladyum (Pd) nanopartikülleri ile modifiye edilmiş camsı karbon elektrot (GCE) elektrodu kullanılmıştır. Sensörün hazırlanma süreci iki basit aşamada gerçekleştirilmiştir: (i) Elektrodun polimer filmiyle kaplanması, (ii) Pd nanopartiküllerinin polimer yapısına immobilize edilmesi. Modifiye elektrodun hazırlanma koşullarının optimize edilmesi için kronoamperometri yöntemi kullanılmıştır. Bu amaçla modifiye elektrot sistemi pH=7.0 fosfat tamponunda (PBS) kronoamperometrik (CA) koşullarda dengeye getirildikten sonra stok H2O2 çözeltisinden eklemeler yapılarak elde edilen akım artışları kaydedilmiş ve en yüksek akımın sağlandığı deneysel koşul optimum koşul olarak kabul edilmiştir. Elde edilen sensörün hazırlanması kolay, ekonomik, seçiciliği yüksek ve hassas bir sensör olduğu ve hızlı bir cevap süresine sahip olduğu deneysel çalışmalarla ortaya konmuştur. Ürik asit, askorbik asit ve dopamin moleküllerinin H2O2 sinyaline girişim etkisi incelenmiş ve bu moleküllerin fizyolojik seviyelerde sensöre girişim yapmadığı gözlenmiştir. Ayrıca optimum koşullarda hazırlanan modifiye elektrot sistemi dönüşümlü voltametri, elektrokimyasal empedans spektroskopisi ve taramalı elektron mikroskobu ile görüntüleme yöntemleri kullanılarak elektrokimyasal ve fiziksel olarak karakterize edilmiştir.,The purpose of the current thesis is to develop a simple, cost-effective and fast amperometric sensor for detection of hydrogen peroxide (H2O2), which is an important molecule in biological systems. For the sensor, a glassy carbon electrode (GCE) which was modified with the conducting poly(thionine) (PTH) polymer and palladium (Pd) nanoparticles was used as the working electrode. The preparation route of the sensor involved two facile steps: (i) Coating the electrode with the polymer film, (ii) Immobilization of Pd nanoparticles into the polymer matrix. Chronoamperometry method was used for optimization of the experimental parameters. For this purpose, aliquots of stock solution of H2O2 was added to phosphate buffer solution (PBS, pH=7.0) under chronoamperometric conditions and the current increase was used as the criteria for determining the optimum conditions. It was revealed from the experimental results that the prepared sensor was easy-toprepare, economical, selective and sensitive with a fast response time. Interference of uric acid, ascorbic acid and dopamine molecules have been studied and it was found that these molecules did not have significant interference at physiological levels. Moreover, the modified electrode system prepared under optimum conditions was characterized electrochemically and physically by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy methods.

The purpose of the current thesis is to develop a simple, cost-effective and fast amperometric sensor for detection of hydrogen peroxide (H2O2), which is an important molecule in biological systems. For the sensor, a glassy carbon electrode (GCE) which was modified with the conducting poly(thionine) (PTH) polymer and palladium (Pd) nanoparticles was used as the working electrode. The preparation route of the sensor involved two facile steps: (i) Coating the electrode with the polymer film, (ii) Immobilization of Pd nanoparticles into the polymer matrix. Chronoamperometry method was used for optimization of the experimental parameters. For this purpose, aliquots of stock solution of H2O2 was added to phosphate buffer solution (PBS, pH=7.0) under chronoamperometric conditions and the current increase was used as the criteria for determining the optimum conditions. It was revealed from the experimental results that the prepared sensor was easy-toprepare, economical, selective and sensitive with a fast response time. Interference of uric acid, ascorbic acid and dopamine molecules have been studied and it was found that these molecules did not have significant interference at physiological levels. Moreover, the modified electrode system prepared under optimum conditions was characterized electrochemically and physically by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy methods.