https://repository.kopri.re.kr/handle/201206/5352 Tue, 21 Apr 2026 10:18:19 GMT 2026-04-21T10:18:19Z https://repository.kopri.re.kr/handle/201206/10914 Title: Optimization of suspect and non-target analytical methods using GC/TOF for prioritization of emerging contaminants in the Arctic environment Authors: Lee, Sunggyu; Kim, Kitae; Jeon, Junho; Moon, Hyo-Bang Abstract: Numerous chemicals have been manufactured through industrial activities and used as consumer products since the late 18th century. Non-target analysis is a new analytical tool to detect many chemicals in environmental samples and to prioritize emerging contaminants. In this study, suspect and non-target analytical methods were optimized using gas chromatography coupled with time-of-flight (GC/TOF) to propose contaminants of emerging concern for the Arctic environment. A suspect analytical method was developed with qualification and qualifier ions, isotopic ratios, and retention times of 215 contaminants including persistent organic pollutants (POPs) to establish an in-house library. Non-target analytical method was also optimized with a deconvoluted ion chromatogram, which is a form that can possibly match the mass spectrum of the NIST library. Multiple environmental samples, such as seawater, air, soil, sediment, sludge, and iceberg, collected from the Arctic region were analyzed with suspect and non-target analysis of GC/TOF after the clean-up procedure with a solid phase extraction (SPE) cartridge. The commonly detected contaminants in the Arctic environmental samples were siloxanes, organophosphate flame retardants, phthalates, synthetic musk compounds, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Among them, siloxanes and organophosphate flame retardants were proposed to be contaminants of emerging concerns for the Arctic environment. This is the first report to prioritize emerging contaminants in the Arctic environment with suspect and non-target analysis of GC/TOF. Tue, 01 Oct 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10914 2019-10-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/9465 Title: Activation of Periodate by Freezing for the Degradation of Aqueous Organic Pollutants Authors: Yoon, Ho Il; Kim, Jungwon; Kim, Kitae; Dominik Heger; Lubica Vetrakova; Lee, Changha; Choi, Yejin Abstract: A new strategy (i.e., freezing) for the activation of IO4？ for the degradation of aqueous organic pollutants was developed and investigated. Although the degradation of furfuryl alcohol (FFA) by IO4？ was negligible in water at 25 °C, it proceeded rapidly during freezing at ？20 °C. The rapid degradation of FFA during freezing should be ascribed to the freeze concentration effect that provides a favorable site (i.e., liquid brine) for the proton-coupled degradation process by concentrating IO4？, FFA, and protons. The maximum absorption wavelength of cresol red (CR) was changed from 434 nm (monoprotonated CR) to 518 nm (diprotonated CR) after freezing, which confirms that the pH of the aqueous IO4？ solution decreases by freezing. The degradation experiments with varying experimental parameters demonstrate that the degradation rate increases with increasing IO4？ concentration and decreasing pH and freezing temperature. The application of the IO4？/freezing system is not restricted to FFA. The degradation of four other organic pollutants (i.e., tryptophan, phenol, 4-chlorophenol, and bisphenol A) by IO4？, which was negligible in water, proceeded during freezing. In addition, freezing significantly enhanced the IO4？-mediated degradation of cimetidine. The outdoor experiments performed on a cold winter night show that the IO4？/freezing system for water treatment can be operated without external electrical energy. Thu, 12 Apr 2018 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/9465 2018-04-12T00:00:00Z https://repository.kopri.re.kr/handle/201206/6282 Title: Accelerated redox reaction between chromate and phenolic pollutants during freezing Authors: Kim, Kitae; Kim, Jaesung; Lee, Changha; Seo, Jiwon; Dominik Heger; Lubica Vetrakova; Kim, Jungwon; Ju, Jinjung; Yoon, Ho Il Abstract: The redox reaction between 4-chlorophenol (4-CP) and chromate (Cr(VI)) (i.e., the simultaneous oxidation of 4-CP by Cr(VI) and reduction of Cr(VI) by 4-CP) in ice (i.e., at ？20 °C) was compared with the corresponding reaction in water (i.e., at 25 °C). The redox conversion of 4-CP/Cr(VI), which was negligible in water, was significantly accelerated in ice. This accelerated redox conversion of 4-CP/Cr(VI) in ice is ascribed to the freeze concentration effect occurring during freezing, which excludes solutes (i.e., 4-CP and Cr(VI)) and protons from the ice crystals and subsequently concentrates them in the liquid brine. The concentrations of Cr(VI) and protons in the liquid brine were confirmed by measuring the optical image and the UV-visible absorption spectra of cresol red (CR) as a pH indicator of frozen solution. The redox conversion of 4-CP/Cr(VI) was observed in water when the concentrations of 4-CP/protons or Cr(VI)/protons increased by 100/1000-fold. These results corroborate the freeze concentration effect as the reason for the accelerated redox conversion of 4-CP/Cr(VI) in ice. The redox conversion of various phenolic pollutants/Cr(VI) and 4-CP/Cr(VI) in real wastewater was successfully achieved in ice, which verifies the environmental relevance and importance of freezing-accelerated redox conversion of phenolic pollutants/Cr(VI) in cold regions. Sun, 01 Jan 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/6282 2017-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/6312 Title: Freezing-enhanced reduction of chromate by nitrite Authors: Kim, Kitae; Kim, Jungwon; Ju, Jinjung; Chung, Hyun Young Abstract: The redox reactions between pollutants and chemicals (e.g., pollutant, oxygen, and water) critically affect the fate and potential risk of pollutants, and their rates significantly depend on the environmental media. Although the kinetics and mechanism of various redox reactions in water have been extensively investigated, those in ice have been hardly explored, despite the large areal extent of the cryosphere, which includes permafrost, polar regions, and mid-latitudes during the winter season on Earth. In this study, we investigated the reduction of chromate (Cr(VI)) by nitrite (NO2？) in ice (i.e., at ？20 °C) in comparison with its counterpart in water (i.e., at 25 °C). The reduction of Cr(VI) by NO2？ was limited in water, whereas it was significant in ice with the simultaneous oxidation of NO2？ to nitrate (NO3？). This enhanced Cr(VI) reduction by NO2？ in ice is most likely due to the freeze concentration effect, that concentrates Cr(VI), NO2？, and protons (at acidic conditions) in the liquid brine (the liquid region among solid ice crystals). The increased thermodynamic driving force for the redox reaction between Cr(VI) and NO2？ by the freeze concentration effect (i.e., the increase in concentrations) enhances the reduction of Cr(VI) by NO2？. The freezing-enhanced Cr(VI) reduction by NO2？ was observed under the conditions of NO2？ concentration = 20 μM？2 mM and pH = 2？4, which are often found in real aquatic systems contaminated by both Cr(VI) and NO2？. The reduction kinetics of Cr(VI) in real Cr(VI)-contaminated wastewater (electroplating wastewater) during freezing was significant and comparable to that in the artificial Cr(VI) solution. This result implies that the proposed ice/Cr(VI)/NO2？ process should be relevant and feasible in real cold environments. Sun, 01 Jan 2017 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/6312 2017-01-01T00:00:00Z