Razvoj analiznih metod za spremljanje fotorazgradnih produktov adsorbiranih onesnaževal na mikroplastiki

Pok, Špela (avtor), Prosen, Helena (mentor)

Razširjena in vse pogostejša uporaba plastike ter njeno odlaganje v okolje generirajo velike količine plastičnih odpadkov po vsem svetu. Bolj kot k sami razgradnji, so polimeri nagnjeni k razpadu na vse manjše delce. Le-ti se v velikosti pod 5 mm imenujejo mikroplastika (MP), ki je danes prepoznana kot sodobno onesnaževalo. Poleg različnih negativnih učinkov na organizme, lahko delci MP v okolje sproščajo svoje dodatke in delujejo kot vektorji z adsorpcijo onesnaževal. Interakcija je odvisna od številnih parametrov in kot taka predstavlja zanimivo področje pri raziskovanju vpliva teh onesnaževal na okolje. Cilj mojega raziskovalnega dela je bil razviti analizne metode za določanje izbranih onesnaževal in njihovih fotorazgradnih produktov, nastalih ob adsorpciji na mikroplastiko. Poskusi so bili narejeni na modelnih sistemih ftalatov (dimetil, dietil in dibutil ftalat), policikličnih aromatskih ogljikovodikov (naftalen, acenaften, fenantren in fluoranten) in bisfenolov (A in S). Kot osnova je bila razvita metoda GC-MS, vendar sta bili zaradi nehlapnosti bisfenolov dodani še metodi HPLC-DAD in LC-MS/MS. Linearnost metod je bila preverjena in potrjena v koncentracijskem območju 3-15 mg/L, v katerem so bila tudi onesnaževala v modelnih vzorcih po fotorazgradnji. Le-to so izvedli na Morski biološki postaji Piran. Končni vzorci, namenjeni za nadaljnje analize in identifikacijo produktov, so bili vodne raztopine že desorbiranih spojin z mikroplastike. Za potrebe dodatnega predkoncentriranja analitov sem nato preizkusila še več variacij ekstrakcij tekoče-tekoče in ekstrakcij na trdno fazo. Slednja se je z uporabo LC-8 kolonic izkazala kot najboljša za pripravo vzorcev in analizo produktov razgradnje. Razvite metode sem uporabila pri analizi modelnih vzorcev po fotorazgradnji na mikroplastiko adsorbiranega dibutil ftalata, bisfenola A, naftalena in acenaftena. Z LC-MS/MS sem identificirala večino nastalih razgradnih produktov prvih treh spojin, v kromatogramih po analizi vzorca acenaftena pa nisem zaznala nobenih vrhov razgradnih produktov.

• Jezik: Slovenski jezik
• Ključne besede: ftalati, policiklični aromatski ogljikovodiki, bisfenoli, fotorazgradnja, mikroplastika, GC-MS, LC-MS/MS
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: FKKT - Fakulteta za kemijo in kemijsko tehnologijo
• Leto izida: 2023
• PID: 20.500.12556/RUL-148404
• COBISS.SI-ID: 163009795
• Datum objave v RUL: 22.08.2023

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Development of analytical methods for monitoring of photodegradation products of pollutants adsorbed on microplastics

Izvleček

Widespread and growing use of plastics with irresponsible disposal generate large amounts of its debris worldwide. The polymers are more prone to break into smaller particles than to decompose. Particles smaller than 5 mm are named microplastics (MP) and are today recognised as modern pollutants. In addition to various negative effects on organisms, MP can release its additives and act as vector by adsorbing pollutants. The interaction depends on several parameters and represents an interesting area of research on the impact of these pollutants on the environment. The aim of my research was to develop analytical methods for the detection of selected pollutants and their photodegradation products formed upon adsorption on microplastics. Experiments were performed on model systems of phthalates (dimethyl, diethyl, and dibutyl phthalate), polycyclic aromatic hydrocarbons (naphthalene, acenaphthene, phenanthrene, and fluoranthene) and bisphenols (A and S). Firstly, GC-MS method was developed, but due to the non-volatility of bisphenols, HPLC-DAD and LC-MS/MS methods were added. The linearity of methods was tested and validated in the concentration range 3-15 mg/L, where the pollutants in the model samples were expected to be. Photodegradation experiments were carried out at the Marine Biology Station Piran. The final samples intended for further analysis and identification of photoproducts were aqueous solutions of compounds already desorbed from the microplastics. For additional preconcentration, I tested several variations of liquid-liquid and solid phase extractions. The latter, by using LC-8 cartridges, proved to be the best for sample preparation and analysis of degradation products. Developed methods were applied to model samples after photodegradation od dibutyl phthalate, bisphenol A, naphthalene, and acenaphthene. Using LC-MS/MS, I identified most of the resulting degradation products of the first three analytes, while no degradation product peaks were detected in the chromatograms of the acenaphthene sample.

• Ključne besede: phthalates, polycyclic aromatic hydrocarbons, bisphenols, photodegradation, microplastics, GC-MS, LC-MS/MS