Endokrin bozucu bazı kimyasalların seçici ve hassas sensörlerle tayini

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Thesis Type: Doctorate

Institution Of The Thesis: Ankara University, Sağlık Bilimleri Enstitüsü, temel eczacılık bilimleri, Turkey

Approval Date: 2022

Thesis Language: Turkish

Student: SARİYE İREM KAYA

Supervisor: Sibel Ayşıl Özkan

Open Archive Collection: AVESIS Open Access Collection

Abstract:

Within the scope of this doctoral thesis, molecularly imprinted polymer (MIP) based electrochemical sensors were developed for the selective and sensitive determination of bisphenol A (BPA), bisphenol s (BPS) and bisphenol F (BPF), the most important group of endocrine disrupting chemicals. 5 mM [Fe(CN)6]3−/4– solution was used as the redox probe in all electrochemical measurements. Non-imprinted polymer (NIP) was used to control the performance of the sensors. During the preparation of the MIP based electrochemical sensor for the sensitive, selective and rapid determination of BPA, electropolymerization was performed with the functional monomer aniline. For the characterization of the MIP(ANI)/GCE sensor, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and contact angle measurements were performed. The MIP(ANI)/GCE sensor has a linear range of 1x10-15 M - 8x10-15 M for standard solution and serum, and limit of detection (LOD) and limit of quantification (LOQ) values at femtomolar level. The accuracy of the sensor was demonstrated by recovery studies in serum and plastic bottled water samples. Imprinting factor (IF) and interference studies also proved the selectivity. This sensor is a very useful, highly sensitive and selective, low cost and reliable option for BPA analysis. For the electrochemical analysis of BPS, a MIP-based sensor was prepared by photopolymerization with the amino acid-based functional monomer N-methacryloyl-L-tyrosine. For the characterization study of the sensor, CV, EIS, SEM and FTIR methods were used. The linear range of the MA-Tyr@MIP/GCE sensor was found as 1x10-15 M - 1x10-14 M, while LOD and LOQ were calculated as 0.171 fM and 0.569 fM. Good recovery values obtained with serum and plastic bottled water samples showed that the sensor could be successfully applied to these samples. A 14-day stability assessment demonstrated that the sensor had high stability up to day 5. IF studies also show that this sensor has high selectivity with stability, sensitivity and repeatability. For the selective and sensitive analysis of BPF, a porous MIP-based electrochemical sensor was prepared using L-Tryptophan as functional monomer, tetraethyl orthosilicate and cetyltrimethylammonium bromide. SEM, Raman spectroscopy, CV and EIS were used to characterize the MIP surface. The linear range of the MIP(TEOS:L-Trp)@GCE sensor for standard solution and serum sample was found as 1x10-15 M - 1x10-14 M. The LOD and LOQ showing the high sensitivity of the sensor were calculated as 0.291 fM and 0.971 fM. Good recovery% values obtained with plastic bottled water and serum samples indicated the accuracy of the sensor. Interference and IF analyzes proved high selectivity. Also, the sensor has been found to be stable up to 5 days. The MIP(TEOS:L-Trp)@GCE sensor is a sensitive, stable, selective and easy-to-apply option for BPF determination. Consequently; it was shown that the MIP-based sensors developed for the electrochemical analysis of BPA, BPS and BPF are more advantageous and alternative methods for bisphenol analysis compared to existing methods.