• Title, Summary, Keyword: chemical analysis

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Temperature-dependent studies on catalytic hydrosilation of polyalkylsiloxane using NMR

  • Sul, Hyewon;Lee, Tae Hee;Lim, Eunsoo;Rho, Yecheol;Kim, Chong-Hyeak;Kim, Jeongkwon
    • Analytical Science and Technology
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    • v.30 no.4
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    • pp.213-219
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    • 2017
  • Polyalkylsiloxane has been spotlighted in pressure-sensitive adhesive (PSA) application due to excellent physical properties and good biocompatibility. Thermal behaviour of polyalkylsiloxane mixtures, such as thermal stability and heat flow, were studied using TG-DTA during catalytic hydrosilation. To understand reaction kinetics of cross-linking, catalytic hydrosilation of polyalkylsiloxane was monitored using variable temperature nuclear magnetic resonance (VT-NMR) as increased temperature. The formation of cross-linking bond $Si-CH_2-CH_2-Si$ was directly observed using distortionless enhanced by polarization transfer (DEPT) technique. Successfully polyalkylsiloxane PSA samples exhibited excellent adhesion properties by cross-linking reaction.

Analysis of Chemical Warfare Agents in Water Using Single-Drop Microextraction

  • Park, Yang-Gi;Kim, Sung-Ki;Choi, Ki-Hwan;Son, Byung-Hoon;Park, Ju-Sub;Kang, Hong-Ku
    • Bulletin of the Korean Chemical Society
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    • v.30 no.1
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    • pp.49-52
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    • 2009
  • Single-drop microextraction (SDME) is an extraction methodology where the drop plays an essential role as extracts. It was evaluated for the GC-MS determination of nerve agents, one class of the chemical warfare agents (CWAs). Since these nerve agents are highly toxic, it is important to detect the nerve agents in the environmental samples. Several affecting factors including extraction solvents, stirring rate, extraction time, and amounts of salt were optimized. The limit of detections (LODs) were 0.1 - 10 ng/mL and the relative standard deviations (RSDs%, n=5) were in the range of 6.3% to 9.0% for four nerve agents. Without pretreatment of the environmental samples, 5-103 fold enrichments and 48-100% recovery were accomplished. These results demonstrated the feasibility of this method for on-site and off-site analysis of water sample collected from suspicious CWAs site.