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Benzotriazol in njegovi derivati so strupene heterociklične spojine, ki so dandanes nepogrešljive za industrijo. Njihova prisotnost v okolju ima škodljiv vpliv na rastline, vodne organizme in ljudi. Običajno jih določamo z ekstrakcijo in predkoncentracijo skupaj z občutljivimi analitskimi tehnikami, kot je na primer LC-MS/MS. Občasno se določanje izvaja tudi s tehniko HPLC-DAD. Ena izmed mikroekstrakcijskih tehnik je mikroekstrakcija z votlim vlaknom (HFME). Slednjo sem v svojem delu uporabila za ekstrakcijo šestih polarnih benzotriazolov iz vodovodne vode in nato iz različnih rečnih vzorcev. Tehnika zaradi učinkovite predkoncentracije zagotavlja visoke obogatitvene faktorje (EF) in je dobra alternativa klasičnim tehnikam. Poleg tega je pri tehniki HFME poraba škodljivih organskih topil zmanjšana na minimum. V svojem delu sem optimizirala pH-vrednost vzorca in koncentracijo dodane raztopine EDTA, ki je služila kot ligand za moteče kovinske ione, prisotne v vodovodni vodi. Preizkušala sem tudi vpliv organskega topila (metanola) na učinkovitost ekstrakcije. Optimizacija je bila opravljena s tekočinsko kromatografijo, sklopljeno z detektorjem s serijo diod (HPLC-DAD). Najbolj učinkovita ekstrakcija je bila dosežena pri pH-vrednosti 6 z dodatkom 100 μL 0,1 M raztopine EDTA. Z optimizirano metodo sem na dveh koncentracijskih ravneh (0,1 mg/L in 2 mg/L) ocenila še matrične učinke pri določanju benzotriazolov v reki Glinščici. Analize so bile opravljene s tekočinsko kromatografijo, sklopljeno s tandemsko masno spektrometrijo (LC-MS/MS). Matrični učinki so bili znatni, kar je lahko posledica ostalih komponent, prisotnih v ekstraktu. Na koncu sem optimizirano metodo uporabila za določitev koncentracij polarnih benzotriazolov v reki Krki in Ljubljanici. Večina koncentracij analitov je bila pod mejo zaznave (LOD) metode. Izjema so bile koncentracije BTZ, ClBZ in DMBZ v Ljubljanici, ki je bila vzorčena za čistilno napravo. Benzotriazole and its derivatives are toxic heterocyclic compounds which are nowadays indispensable for industry. They have been found in environment, causing harmful effects on plants, aquatic organisms, and humans. Their determination usually includes extraction and preconcentration, coupled to sensitive analytical techniques, such as LC-MS/MS, occasionally also HPLC-DAD. One of the existing microextraction techniques is hollow fiber microextraction (HFME), which was used in this work for extraction of six polar benzotriazoles from tap water and further from different river samples. Due to efficient preconcentration, this technique provides high enrichment factors and is a good substitute for classical techniques. Additionally, with the use of HFME, the consumption of harmful organic solvents is decreased to a minimum. In this work, pH of the sample and concentration of EDTA added as a ligand for metal ions in tap water were optimized. Furthermore, impact of organic solvent (methanol) on extraction efficiency was examined. Optimization was carried out with liquid chromatography coupled with diode array detector (HPLC-DAD). The most efficient extraction was achieved when the pH of the sample was 6 and 100 μL of 0.1 M EDTA was added. After optimization, matrix effects for the determination of benzotriazoles in Glinščica river water were estimated at two concentration levels: 0.1 mg/L and 2 mg/L. Analyses were carried out with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Matrix effects were considerable, which can be the consequence of other compounds present in the extract. Finally, the optimized HFME method was used for determination of polar benzotriazole concentrations in river Krka and Ljubljanica. Analyte concentrations were mostly below limit of detection (LOD) of the method, expect for concentrations of BTZ, ClBZ and DMBZ in Ljubljanica, sampled behind the wastewater treatment plant. |
