THE DETERMINATION OF DOPAC OVER POLYANILINEPOLY( 3-METHYLTHIOPHENE)-POLY(3,3’- DIAMINOBENZIDINE) ELECTRODE

Year 2015, Volume: 2 Issue: 3, 36 - 41, 09.06.2015

Muammer Kavanoz Emine Ülker

Abstract

3,4-dihydroxyphenylacetic acid (DOPAC) which is important metabolite of dopamine is an important biological molecules [1]. DOPAC with dopamine play an important role in the treatment of neurological disorders such as schizophrenia [2], epilepsy [3], Parkinson's disease [4] Alzheimer [5]. Because of the physiological importance, accurate and reliable determination of DOPAC is important clinically. The redox property of DOPAC allows its electrochemical detection. Various modified electrodes
with conductive polymer were used for the determination of DOPAC in the literature [6].
In this study, Polyaniline - Poly(3-methylthiophene) - Poly(3,3’-diaminobenzidine) (PANI - P3MT - PDAB) film which has PANI and P3MT (good conductive polymers) and PDAB (multiple amine functional groups) was potentiodynamically synthesized on Pt disk electrode in methylene chloride layer by layer. For this, green colored PANI film was deposited on Pt disk electrode in methylene chloride containing 100 mM tetrabuthyl ammonium perchlorate (TBAP) / 300 mM aniline / 100 mM HClO4 then
black colored P3MT – PDAB film was deposited on PANI film in methylene chloride containing 100 mM TBAP / 500 mM 3-methylthiophene / 1.0 mM 3,3’-diaminobenzidine. Characterization of PANI-P3MT–PDAB film was performed by UVvis, FT–IR, SEM and EDS methods. This film was used amperometric determination of DOPAC in solution consists of NaHSO4/Na2SO4 (pH 2.0). It was studied at 0.45 V, 0.50 V, 0.55 V and 0.60 V potentials for amperometric determination of DOPAC with this modified electrode. The best analytical data were obtained 0.50 V. Limit of
Detection (LOD), Limit of Quantification (LOQ), the linear response range and regression coefficient (R2) were found as 1.47x10-5 mM, 4.49x10-5 mM, 4.49x10-5 – 2.0 mM and 0.981, respectively.

Keywords

Amperometric determination, 3, 4-dihydroxyphenylacetic acid, polyaniline, poly (3methylthiophene), poly (3, 3'-diaminobenzidine)

POLİANİLİN-POLİ(3-METİLTİYOFEN)-POLİ(3,3’- DİAMİNOBENZİDİN) ELEKTROT ÜZERİNDEN DOPAC TAYİNİ

Abstract

Dopaminin önemli metaboliti olan 3,4-dihidroksifenilasetik asit (DOPAC) önemli bir biyolojik moleküldür [1]. Dopamin ile birlikte DOPAC; sizofreni [2], epilepsi [3], Parkinson [4], alzhemier [5] gibi nörolojik bozuklukların tedavisinde önemli rol oynar. Fizyolojik öneminden dolayı doğru ve güvenilir DOPAC tayini klinik açıdan önem kazanmaktadır. DOPAC’ın redoks özelliği, elektrokimyasal tayinine imkan sağlamaktadır. Literatürde DOPAC tayini için iletken polimerlerden olusan çesitli modifiye elektrotlar kullanılmıstır [6].

Bu çalısmada, iyi bir iletken polimer olan Polianilin (PANI) ve Poli(3-metiltiyofen) (P3MT) ile birden çok amin fonksiyonel gruba sahip Poli (3,3’-diaminobenzidin) (PDAB) polimerlerini içeren PANI - P3MT - PDAB polimer filmi metilen klorür ortamda Pt diskelektrot üzerine tabakalar halinde potansiyodinamik olarak sentezlendi. Bunun için ilk olarak 100 mM tetrabutilamonyum perklorat (TBAP) / 300 mM anilin / 100 mM HClO4
içeren metilen klorür ortamında Pt elektrot üzerine yesil renkli PANI filmi biriktirildi. Daha sonra PANI film üzerine 0.1M TBAP / 500 mM 3-metil tiyofen / 1.0 mM 3,3’- diaminobenzidin içeren metilen klorür çözeltisinde siyah renkli P3MT – PDAB filmi biriktirildi. Elde edilen PANI - P3MT – PDAB filminin karakterizasyonu UV-vis, FT–IR, SEM, EDS metotları kullanılarak yapıldı. Bu modifiye elektrot kullanılarak amperometrik I-t yöntemi ile DOPAC tayini NaHSO4/Na2SO4 (pH 2.0) çözeltisinde gerçeklestirildi. Bunun için 0.45 V ile 0.60 V arasında potansiyellerde çalısıldı. En iyi analitik veriler 0.50 V potansiyelde elde edildi. Bu potansiyelde gözlenebilme sınırı (LOD), tayin sınırı (LOQ), lineer cavap aralığı ve regrasyon katsayısı (R2) sırası ile
1,47x10-5 mM, 4,49x10-5 mM, 4,49x10-5 – 2.0 mM ve 0.981 olarak bulundu.

Keywords

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