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ID 33027
フルテキストURL
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著者
Katsu, Takashi Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
Tsunamoto, Yumi Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
Hanioka, Nobumitsu Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
Komagoe, Keiko Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
Masuda, Kazufumi Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
Narimatsu, Shizuo Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
抄録
Although a previous study [S.S.M. Hassan, M.A. Ahmed, M.M. Saoudi, Anal. Chem. 57 (1985) 1126] had shown that a caffeine-sensitive electrode made with picrylsulfonate and 1-octanol as a cation-exchanger and a solvent mediator, respectively, had a wide working pH range (5.5-9.5) and exhibited a Nernstian response, we could not find such response in this electrode. The present result was reasonable, because the pK, value of caffeinium ion was reported to be around 0.7 and the neutral form of caffeine was predominant in the pH range examined. Thus, we reinvestigated the response characteristics of a caffeine electrode, taking into consideration the pKa value, and constructed a new electrode with a combination of the lipophilic cation-exchanger, tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate (HFPB), and the solvent mediator with high degree of dielectric constant, 2-fluoro-2'-nitrodiphenyl ether (FNDPE). This electrode showed a pH-dependent response to caffeinium ion and gave a detection limit of 50 mu M with a slope of 55 mV per concentration decade at pH 2. The use of other solvent mediators was less effective than that of FNDPE. The electrode was applied for the determination of caffeine in some central stimulants.
キーワード
ion-selective electrode
caffeinium ion
solvent mediator
2-fluoro-2 '-nitrodiphenyl ether
caffeine determination
備考
Published with permission from the copyright holder.
This is published in Analytica Chimica Acta, 2008 Vol.620 Issue.1-2 pp.50-54
Publisher URL: http://dx.doi.org/10.1016/j.aca.2008.05.027
Direct access to Thomson Web of Science record
(C)2008 by Elsevier B.V.
発行日
2008-07-14
出版物タイトル
Analytica Chimica Acta
620巻
1-2号
出版者
Elsevier Science B.V.
開始ページ
50
終了ページ
54
ISSN
0003-2670
NCID
AA00524834
資料タイプ
学術雑誌論文
言語
English
著作権者
Elsevier Science B.V.
論文のバージョン
author
査読
有り
DOI
Web of Sience KeyUT
Submission Path
analytical_chemistry/39