Primerjava analiznih metod za določanje mikroplastike v morskih ribah : magistrsko delo

Lapajne, Patricia (author), Bavcon Kralj, Mojca (mentor), Bajt, Oliver (co-mentor), Trebše, Polonca (reviewer)

Uvod: Plastiko danes uporabljamo povsod. Je vsestranski material, ki nudi zaščito, oporo in je gradnik tehnološke opreme. Plastika razpada na manjše delce, t. i. mikroplastiko (MP), pod zunanjimi pogoji ali pa je v tej velikosti že izdelana (primarna MP). Delci MP so v morju še posebej nevarni za vodne organizme in živali, ki se z njimi nehote prehranjujejo. Do sekundarnega zaužitja pa prihaja pri večjih ribah (tudi morskih sesalcih in pticah), ki plenijo organizme z že vsebovanimi delci MP. Za določanje količine delcev MP uporabljamo mikroskopske metode, za določevanje vrste polimera pa infrardečo spektroskopijo s Fourierovo transformacijo (FT-IR), Ramansko spektroskopijo, plinsko kromatografijo z masnim detektorjem (GC-MS), metode termične analize in druge metode. Namen: Preučiti občutljivost dveh detekcijskih metod za določanje MP v ribah in izvesti analizo na realnih vzorcih rib iz Tržaškega zaliva. Metode dela: Primerjali smo dve metodi za določanje delcev MP v okoljskih vzorcih, prvo metodo za določanje MP v morskih ribah, ki temelji na zaznavanju značilnih hlapnih organskih spojin z GC-MS, in drugo, standardno metodo za določanje vrste polimerov s FT-IR spektroskopijo. Rezultati: S preiskovalno metodo z GC MS smo ugotovili, da so hlapne spojine preiskovanih polimerov zaznavne v skupni zmesi polimerov in ribje drobovine za PE, PP, PS in PVC pri najmanjši masi 20 mg posameznega polimera; pri tem polimer PET ni zaznaven. V analizi posameznega polimera in ribje drobovine je bila najnižja masa določljivosti dosežena pri polimeru vrste PE, pri masi 2 mg. V realnih vzorcih rib so bili identificirani trije delci MP kot PE, njihova velikost je bila pod 500 µm in masa pod 2 mg, zato smo se odločili, da jih identificiramo z metodo na mikro-FT-IR spektroskopu. Razprava in zaključek: Delce iz realnih vzorcev smo uspešno identificirali s pomočjo mikro-FT-IR spektroskopije. Trdimo lahko, da je metoda z GC-MS uspešna pri določanju delcev MP nad maso 2 mg pri PE in skupno kot zmes polimerov PE, PP, PS in PVC nad maso 20 mg. Preiskovana metoda z GC-MS se bo z nadaljnjimi izboljšavami lahko uporabljala kot alternativna metoda za določanje MP v okoljskih vzorcih, vendar je omejena z minimalno maso vzorca polimera, kar lahko zaobidemo z analizo združenih vzorcev.

• Language: Slovenian
• Keywords: magistrska dela, sanitarno inženirstvo, mikroplastika, GC-MS, morske ribe, analizne metode, zdravstvena ekologija
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: ZF - Faculty of Health Sciences
• Place of publishing: Ljubljana
• Publisher: [P. Lapajne]
• Year: 2022
• Number of pages: 65 str.
• PID: 20.500.12556/RUL-136178
• UDC: 614
• COBISS.SI-ID: 104989187
• Publication date in RUL: 15.04.2022

Secondary language

• Language: English
• Title: Comparison of analytical methods for determining microplastics in sea fish : master's thesis

Abstract

Introduction: Plastic is widely used everywhere. It is a versatile material, which provides protection and support, and is used as a building block of technological equipment. Plastic degrades into smaller pieces—microplastics (MP)—due to environmental conditions, or it is manufactured in this size—i.e., primary MP. MP particles in the sea are particularly dangerous for sea life and animals that can feed on MP unintentionally. Secondary ingestion is seen in larger fish (also sea mammals and birds) that feed on organisms already containing MP pieces. Microscopic methods are used for determining the quantity of MP particles, and infrared spectroscopy with Fourier transformation (FT-IR), Raman spectroscopy, gas chromatography with mass detector (GC-MS), thermal analysis, and other methods are used for determining the MP polymer types. Purpose: To study the sensitivity of two MP detection methods in fish and to analyse real samples of fish from the Gulf of Trieste. Methods: Two methods for determining MP particles in environmental samples were compared: method one for determining MP particles in sea fish, which is based on detecting characteristic volatile organic compounds with GC-MS; and another standard method for determining the polymer type with FT-IR spectroscopy. Results: The GC-MS method of analysis showed that volatile organic compounds in the studied polymers can be detected in the mixture of polymers and fish entrails for PE, PP, PS and PVC at the lowest mass of 20 mg for each polymer. The PET polymer was not detected. When analysing each polymer and fish entrails, the lowest detection mass was seen in the PE polymer at 2 mg. In the real samples of sea fish, three MP particles were determined as PE, their size was under 500 μm and mass under 2 mg. Consequently, we decided to determine the polymer type with the micro-FT-IR spectroscope method. Discussion and conclusion: MP particles from real samples were successfully determined with micro-FT-IR spectroscopy. It can be claimed that the GC-MS method is successful in determining MP particles with a mass of more than 2 mg for PE, and more than 20 mg for a combination of PE, PP, PS and PVC polymers. With further improvements, the GC-MS method of analysis will be used as an alternative method for determining MP in environmental samples; it is, however, limited by the lowest mass of the sample polymer, which can be avoided by analysing combined samples.

• Keywords: master's theses, sanitary engineering, microplastics, GC-MS, sea fish, methods of analysis, environmental health