Optimizacija ekstrakcijske metode za oksidirane produkte PAH

Bordon, Samo (author), Prosen, Helena (mentor)

Policiklični aromatski ogljikovodiki so pomembna skupina organskih spojin, saj zaradi svoje preproste sinteze in pozitivnih reakcijskih lastnosti predstavljajo izhodiščno točno za sintezo mnogih kompleksnejših spojin. Mnoge raziskave pa so pokazale negativne lastnosti PAH-ov, izkazalo se je namreč, da je mnogo poliaromatskih spojin endokrinih motilcev, mutagenih ter kancerogenih. Njihova razširjenost in negativni vplivi na okolje, kot tudi na žive organizme v njem, je razlog, da se onesnaževala raziskuje in analizira. PAH-i predstavljajo velik okoljski problem sploh v morjih, kjer lahko nekontrolirano migrirajo in poškodujejo organizme. Prav zaradi njihove reaktivnosti in hitrih migracij med ekosistemi sem svojo diplomsko delo namenil optimizaciji ekstrakcijske metode na trdno fazo za pet poliaromatskih spojin, in sicer naftalen, acenaften, 2-naftol, 2,7-naftalendiol in acenaftenkinon. Cilj diplomskega dela je bil poiskati optimalne ekstrakcijske pogoje za naštete poliaromate. Preveril sem, kateri sorbent je primeren, kako na izkoristek ekstrakcije vplivata pH in prisotnost nevtralne soli v vzorcu, preizkusil pa sem tudi ekstrakcijske parametre, kot so elucijsko topilo, volumen elucijskega topila in prebojni volumen, z namenom poiskati najvišji izkoristek ekstrakcije. Poskusi so pokazali, da je za ekstrakcijo PAH-ov najprimernejša C8 (Supelco) ekstrakcijska kolona. Pri izbiri elucijskega topila in njegovega volumna je izkoristek bil najboljši ob uporabi 4 mL 100 % acetonitrila, najboljša oblika vrhov v HPLC kromatogramu pa se je izrisala ob redčenju eluata z Milli-Q vodo v razmerju ACN : Milli-Q = 70 : 30. Sprememba pH vrednosti vhodnega vzorca izkoristka ni spremenila, medtem ko je dodatek nevtralne soli (NaCl) izkoristek ekstrakcije povečal za nekaj odstotkov. Končni izkoristki metode so za osnovne poliaromate (naftalen, acenaften) bili med 47 % in 65 %, za razgradne produkte (acenaftenkinon, 2-naftol, 2,7-naftalendiol) pa so izkoristki dosegli vrednosti med 85 % in 110 %.

• Language: Slovenian
• Keywords: : policiklični aromatski ogljikovodiki, razgradni produkti, ekstrakcija na trdno fazo, tekočinska kromatografija visoke ločljivosti (HPLC)
• Work type: Bachelor thesis/paper
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-160776-ad4347dc-c5a0-5ef6-7d64-61e3b8dd96c7
• Publication date in RUL: 04.09.2024

Secondary language

• Language: English
• Title: Optimisation of extraction method for oxidised PAH products

Abstract

Polycyclic aromatic hydrocarbons are an important group of organic compounds because their simple synthesis and positive reaction properties make them the starting point for the synthesis of many more complex compounds. However, many studies have shown the negative properties of PAHs, as many polyaromatic compounds have been shown to be endocrine disruptors, mutagens and carcinogens. Their widespread occurence and their negative effects on the environment, as well as on the living organisms in it, are the reasons to investigate and analyse these organic pollutants. PAHs are a major environmental problem, particularly in the sea, where they can migrate uncontrollably and damage organisms. It is because of their reactivity and rapid migration between ecosystems that I dedicated my thesis to the optimisation of a solid-phase extraction method for five polyaromatic compounds: naphthalene, acenaphthene, 2-naphthol, 2,7-naphthalenediol and acenaphtoquinone. The aim of the thesis was to find the optimal extraction conditions for the polyaromatics listed. I checked which sorbent is suitable, how the extraction efficiency is affected by pH and the presence of neutral salt in the sample, and I tested extraction parameters such as elution solvent and its volume and breakthrough volume in order to find the highest extraction efficiency. The experiment showed that the C8 (Supelco) extraction column is the most suitable for the extraction of PAHs. The choice of elution solvent and its volume gave the best yield when 4 mL of 100% acetonitrile was used, while the shape of the peaks in the HPLC chromatogram was optimal when the eluate was diluted with Milli-Q water in the ratio ACN : Milli-Q = 70 : 30. Changing the pH value of the input sample did not change the yield, while the addition of a neutral salt (NaCl) increased the extraction yield by a few %. The final recoveries of the method for the parent polyaromatics (naphthalene, acenaphthene) were between 47% and 65%, while for the degradation products (acenaphthoquinone, 2-naphthol, 2,7-naphthalenediol) recoveries were between 85% and 110%.

• Keywords: Polycyclic aromatic compound, degradation products, solid phase extraction, high resolution liquid chromatography (HPLC)