Določanje klorofenolov v površinskih vodah

Mitevski, Ivan (author), Prosen, Helena (mentor)

Klorofenoli so klorirane organske spojine, ki so zaradi svoje strupenosti, kancerogenosti in mutagenosti potencialno nevarne človeku in okolju. V okolje najpogosteje pridejo s kmetijstvom in farmacevtsko industrijo. Zaradi stabilnosti in nevarnosti za okolje je pomemben razvoj novih tehnik za kvalitativno in kvantitativno določitev klorofenolov v okolju. Namen mojega raziskovalnega dela je bila optimizacija analiznega postopka za kvalitativno in kvantitativno določitev različnih klorofenolov in nato analiza realnih vzorcev. Določal sem 2,4-klorofenol, 2,5-klorofenol, 2,3,4,6-tetraklorofenol in pentaklorofenol. Za analizo sem uporabil HPLC-DAD in PFP kolono. Ker so klorofenoli v realnih vzorcih v zelo nizkih koncentracijah, jih je bilo treba najprej predkoncentrirati. Za ekstrakcijo sem uporabil ekstrakcijo na trdno fazo in C8 reverzno-fazno ekstrakcijsko kolono. Za elucijo sem uporabil acetonitril. Nato sem preveril vpliv pH in ionske moči na izkoristek. Pri pH ≈ 3 se je izkoristek ekstrakcije znatno povečal. Ionska moč raztopine, ki sem jo preveril z dodatkom NaCl, ni imela vpliva. Ker so bili izkoristki še vedno nizki, sem razlog moral iskati v ekstrakcijskem postopku. Razlog je bil v sušenju eluata do suhega in nato raztapljanje v 10 % raztopini acetonitrila v MQ vodi. Zaradi tega sem v končnem postopku eluat posušil le do 1 mL, ga kvantitativno prenesel v 2 mL bučko in z MQ vodo razredčil do oznake. Prebojni volumen je bil nad 200 mL. V končnem postopku sem nanašal 100 mL vzorca. Končni izkoristki ekstrakcije so bili 97,8 % za 2,5-diklorofenol, 87,3 % za 2,4-diklorofenol, 91,7 % za 2,3,4,6-tetraklorofenol in 85,7 % za pentaklorofenol. Ocenjena meja zaznave je bila 0,44 μg/L za 2,5-diklorofenol, 0,60 μg/L za 2,4-diklorofenol, 0,44 μg/L za 2,3,4,6-tetraklorofenol in 0,42 μg/L za pentaklorofenol. Na koncu sem analiziral naravne vzorce iz izvira reke Krupe in sintetske vzorce degradacije klorofenolov pod določenimi pogoji.

• Language: Slovenian
• Keywords: klorofenoli, optimizacija analiznega postopka, HPLC-DAD, ekstrakcija na trdno fazo
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2022
• PID: 20.500.12556/RUL-139934
• COBISS.SI-ID: 128461059
• Publication date in RUL: 08.09.2022

Secondary language

• Language: English
• Title: Detetermination of chlorophenols in surface waters

Abstract

Chlorophenols are chlorinated organic compounds that are potentially dangerous to humans and the environment due to their toxicity, carcinogenicity, and mutagenicity. They most often enter the environment through agriculture and the pharmaceutical industry. Due to their stability and the danger for environment, the development of new techniques for the qualitative and quantitative determination of chlorophenols in the environment is important. The purpose of my research work was the optimization of the analytical procedure for the qualitative and quantitative determination of various chlorophenols and analysis of real samples. I analysed 2,4-dichlorophenol, 2,5-dichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol. For the analysis, I used HPLC-DAD and a PFP column. Since chlorophenols are present in very low concentrations in real samples, they had to be pre-concentrated first. For the extraction I used solid-phase extraction method and a C8 reverse phase extraction column. I used acetonitrile for elution and checked the effect of pH and ionic strength on the recoveries. At pH ≈ 3, the extraction recovery increased significantly. Ionic strength of the solution was changed by adding NaCl and had no effect. Since the recoveries were still low, I had to look for the reasons in the extraction process. The reason was drying the eluate to dry residue and then dissolving it in a 10 % solution of acetonitrile in MQ water. Therefore, in the final procedure, I dried the eluate only to 1 mL, quantitatively transferred it to a 2 mL flask and diluted to the mark with MQ water. The breakthrough volume was below 200 mL. Therefore, I applied 100 mL of the sample in the final procedure. Final extraction yields were 97.8 % for 2,5-dichlorophenol, 87.3 % for 2,4-dichlorophenol, 91.7 % for 2,3,4,6-tetrachlorophenol, and 85.7 % for pentachlorophenol. The estimated limit of detection was 0.44 μg/L for 2,5-dichlorophenol, 0.60 μg/L for 2,4-dichlorophenol, 0.44 μg/L for 2,3,4,6-tetrachlorophenol, and 0.42 μg/L for pentachlorophenol. Finally, I analyzed natural samples from the Krupa River spring and synthetic samples of the degradation of chlorophenols under certain conditions.

• Keywords: Chlorophenols, optimization of the analytical procedure, HPLC-DAD, solid-phase extraction