Uporaba sitotiskanih elektrod za elektrokemijsko določitev bisfenola S v vodnem mediju

Sodnik, Neža (author), Kralj Cigić, Irena (mentor), Žagar Soderžnik, Kristina (co-mentor)

Bisfenol S (BPS) je eden od komercialno najbolj razširjenih predstavnikov obstojnih in mobilnih spojin (PMC), ki vzbujajo splošno zaskrbljenost zaradi širokega nabora negativnih vplivov na zdravje in okolje. Trend raziskav na področju PMC v zadnjih letih ni usmerjen v klasične kromatografske metode za določitev bisfenolov, ampak k hitrejšim, enostavnejšim in prenosnim načinom določitve, kot so elektrokemijski senzorji. V tem magistrskem delu je bila elektrokemijska določitev BPS izvedena na komercialnih sitotiskanih elektrodah dveh tipov – na osnovi ogljika (SPE-C) in enostenskih ogljikovih nanocevk (SPE-SWCNT). Elektrode so bile uporabljene brez nadaljnjih modifikacij. V prvem delu so bile elektrode uporabljene za meritve s ciklično voltametrijo. Primerne so bile za določitev BPS v širokem koncentracijskem območju (1–400 μM) z nizko mejo zaznave (0,73 μM pri SPE-C in 0,87 μM pri SPE-SWCNT) in ponovljivim odzivom na BPS tekom 16 meritev na eni elektrodi. Z uporabo ciklične voltametrije v kombinaciji s tekočinsko kromatografijo visoke ločljivosti je bil raziskan mehanizem oksidacije BPS na obeh tipih elektrod. V drugem delu so bile elektrode uporabljene za hkratno zaznavo bisfenolov S in bisfenola A (BPA) z uporabo diferenčne pulzne voltametrije. Z obema senzorjema je bilo možno ločiti med BPS in BPA. Pri uporabi SPE-C se je izboljšala občutljivost in meja zaznave BPS (0,37 μM), medtem ko je bila meja zaznave na SPE-SWCNT (1,57 μM) višja kot pri določitvi s ciklično voltametrijo. V tretjem delu je bila ciklična voltametrija na SPE-C uporabljena za analizo 11 realnih vzorcev termo papirja. Pravilnost dobljenih rezultatov je bila preverjena s tekočinsko kromatografijo visoke ločljivosti. Rezultati elektrokemijske določitve so se dobro ujemali z rezultati tekočinske kromatografije, kar potrjuje, da so preiskovane elektrode primerne za kvalitativno in kvantitativno analizo bisfenola S v termo papirju.

• Language: Slovenian
• Keywords: bisfenol S, sitotiskane elektrode, ciklična voltametrija, diferenčna pulzna voltametrija, termo papir
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-151803
• COBISS.SI-ID: 174153475
• Publication date in RUL: 20.10.2023

Secondary language

• Language: English
• Title: The use of screen-printed electrodes for electrochemical determination of bisphenol S in aqueous media

Abstract

Bisphenol S (BPS) is one of the most commercially widespread representatives of persistent and mobile chemicals (PMCs) of general concern due to a wide range of negative health and environmental impacts. The research trend in the field of PMC in recent years is not directed towards classic chromatographic methods for the determination of bisphenols, but towards faster, simpler, and portable methods of determination, such as electrochemical sensors. In this master's thesis, the electrochemical detection of BPS was performed on commercial screen-printed electrodes of two types - carbon-based (SPE-C) and single-walled carbon nanotube-based (SPE-SWCNT). The electrodes were used without further modifications. In the first part, the electrodes were used for cyclic voltammetry measurements. They were suitable for the determination of BPS in a wide concentration range (1–400 μM) with a low detection limit (0.73 μM for SPE-C and 0.87 μM for SPE-SWCNT) and a reproducible response to BPS over the course of 16 measurements on one electrode. Using cyclic voltammetry combined with high-resolution liquid chromatography, the mechanism of BPS oxidation on both types of electrodes was investigated. In the second part, the electrodes were used for the simultaneous detection of bisphenol S and bisphenol A (BPA) using differential pulse voltammetry. With both sensors it was possible to distinguish between BPS and BPA. Using SPE-C improved the sensitivity and detection limit of BPS (0.37 μM), while the detection limit on SPE-SWCNT (1.57 μM) was higher than with cyclic voltammetry detection. In the third part, cyclic voltammetry on SPE-C was used to analyse 11 real thermal paper samples. The correctness of the obtained results was verified by high-resolution liquid chromatography. The results of electrochemical detection were in good agreement with the results of liquid chromatography, which confirms that the investigated electrodes are suitable for the qualitative and quantitative analysis of bisphenol S in thermal paper.

• Keywords: bisphenol S, screen printed electrodes, cyclic voltammetry, differential pulse voltammetry, thermal paper