Aromatik sülfonik asit boyar maddeleriyle modifiye elektrot kullanılarak akışa enjeksiyon analiz sisteminde hidrazinin elektrokatalitik tayini
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Tarih
2018
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Çanakkale Onsekiz Mart Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada kalmagit (Clm), kromotropik asit (Cta), tropeolin (Trp), pirokatekol violet (Pcv) gibi iyi bir redoks mediyatör özelliğine sahip aromatik sülfonik asit boyar maddelerin elektropolimerizasyon ve adsorpisyon yoluyla modifiye kalem grafit elektrot yüzeyine modifikasyonu gerçekleştirilmiş ve hazırlanan bu modifiye elektrotlar ile hidrazinin elektrokatalitik yükseltgenmesi hem döngüsel voltammetri hem de amperometrik tekniklerle incelenmiştir. 0,1 M pH 9,0 fosfat çözeltisinde kaydedilen döngüsel voltammogramlara göre hidrazin, yalın PGE'de yaklaşık 600 mV gibi yüksek bir potansiyelde yayvan bir şekilde yükseltgenirken, Clm ve Pcv modifiye elektrotlarda sırasıyla 300 mV ve 150 mV gibi daha negatif potansiyellerde keskin şekilde yükseltgenmiştir. Bu özellikler, bu iki organik molekülün hidrazinin yükseltgenmesine iyi bir elektrokatalitik aktivite gösterdiğini yansıtmaktadır. Ancak Trp ve Cta ile modifiye PGE'lerde hidrazinin elektrokatalitik yükseltgenmesine iyi yanıt alınamamıştır. Poli-Clm/PGE ve Pcv/PGE ile birlikte daha önceki çalışmalarda ilk defa PGE için geliştirilen fotoelektrokimyasal akış hücresi kullanılarak hidrazinin akış enjeksiyon (Flow Injection, FI) amperometrik tayini de gerçekleştirilmiştir. FI amperometrik çalışmalardan, doğrusal kalibrasyon aralığı/gözlenebilme sınırı (limit of detection, LOD) değerleri Poli-Clm/PGE ve Pcv/PGE için sırasıyla 0,1-100 µM (R2=0,9999)/0,038µM ve 0,25-500 µM (R2=0,9995)/0,08 µM hidrazin olarak bulunmuştur. Geliştirilen FI amperometrik hidrazin sensörünün su örneklerine uygulanabilirliği test edilmiş ve çeşme ve deniz suyu örneklerine ilave edilen hidrazinin %98-102 arasında bir geri kazanımla tayin edilebileceği sonucuna varılmıştır. Ayrıca hidrazinin elektrokatalitik yükseltgenmesine girişim yapan bazı katyonların girişimleri, çözeltiye EDTA ve etilen glikol ilave edilerek giderilmiştir. Bu çalışma sonucunda Poli-Clm/PGE ve Pcv/PGE modifiye elektrotlar kullanılarak, duyarlığı, seçiciciliği ve doğruluğu yüksek amperometrik hidrazin sensörü ilk defa FIA sisteminde geliştirilmiştir.
In this thesis, the modification of four aromatic sulphonic acid dyes such as calmagite (Clm) chromotropic acid (Cta), tropeolin (Trp) and pyrocatechol violet (Pcv) which have a good redox mediator property was performed on pencil graphite electrode (PGE) via electropolymerization and adsorption procedures. Then the electrocatalytic oxidation of hydrazine was investigated by both cyclic voltammetric and amperometric techniques at these prepared modified electrodes. According to cyclic voltammograms recorded in 0.1 M pH 9.0 phosphate solutions, while hydrazine broadly oxidized at a high potential about 600 mV, it sharply oxidized at more negative potentials such as 300 and 150 mV at Clm and Pcv modified electrodes, respectively. Flow injection (FI) amperometric determination of hydrazine was also carried out using Poly-Clm/PGE and Pcv/PGE photoelectrochemical flow cell developed for PGE. From FI amperometric studies, the linear calibration range/limit of detection values were found to be 0.1-100 µM (R2=0.9999)/0.038 µM and 0.25-500 µM (R2=0.9995)/0.08 µM hydrazine at Poly-Clm/PGE and Pcv/PGE, respectively. The applicability of the developed FI amperometric hydrazine sensor to water samples has been tested and the obtained result showed that hydrazine added to tap water and seawater samples can be determined with a recovery of 98-102%. In addition, interferences of some cations on the electrocatalytic oxidation of hydrazine were eliminated by adding of EDTA and ethylene glycol to the solution. As a result, an amperometric hydrazine sensor with high sensitivity, selectivity and accuracy has been developed using Poli-Clm/PGE and Pcv/PGE in FIA system for the first time.
In this thesis, the modification of four aromatic sulphonic acid dyes such as calmagite (Clm) chromotropic acid (Cta), tropeolin (Trp) and pyrocatechol violet (Pcv) which have a good redox mediator property was performed on pencil graphite electrode (PGE) via electropolymerization and adsorption procedures. Then the electrocatalytic oxidation of hydrazine was investigated by both cyclic voltammetric and amperometric techniques at these prepared modified electrodes. According to cyclic voltammograms recorded in 0.1 M pH 9.0 phosphate solutions, while hydrazine broadly oxidized at a high potential about 600 mV, it sharply oxidized at more negative potentials such as 300 and 150 mV at Clm and Pcv modified electrodes, respectively. Flow injection (FI) amperometric determination of hydrazine was also carried out using Poly-Clm/PGE and Pcv/PGE photoelectrochemical flow cell developed for PGE. From FI amperometric studies, the linear calibration range/limit of detection values were found to be 0.1-100 µM (R2=0.9999)/0.038 µM and 0.25-500 µM (R2=0.9995)/0.08 µM hydrazine at Poly-Clm/PGE and Pcv/PGE, respectively. The applicability of the developed FI amperometric hydrazine sensor to water samples has been tested and the obtained result showed that hydrazine added to tap water and seawater samples can be determined with a recovery of 98-102%. In addition, interferences of some cations on the electrocatalytic oxidation of hydrazine were eliminated by adding of EDTA and ethylene glycol to the solution. As a result, an amperometric hydrazine sensor with high sensitivity, selectivity and accuracy has been developed using Poli-Clm/PGE and Pcv/PGE in FIA system for the first time.
Açıklama
Fen Bilimleri Enstitüsü, Kimya Ana Bilim Dalı
Anahtar Kelimeler
Kimya, Chemistry
