122nd General Meeting of the KCS

Type Poster Presentation
Area Analytical Chemistry
Room No. Grand Ballroom
Time 10월 19일 (금요일) 11:00~12:30
Code ANAL.P-327
Subject A Sol-Gel Matrix for the Development of a Thiocyanate-Selective Membrane Electrode
Authors Na Gyeom Kwon, Sung Bae Park1,*
Chemistry, Inje University, Korea
1Department of Chemistry, Inje University, Korea
Abstract In an effort to prepare thiocyanate-selective chemical sensors, an organic-inorganic hybrid sol-gel matrix was used as membrane host for an appropriate sensing material. Tricaprylylmethylammonium thiocyanate (Aliquat336-SCN) was employed as the dissociated ion-exchanger type sensing ionophore. The sol-gel precursor was obtained by the reaction of 3-isocyanatopropyltriethoxysilane with 1,4-butanediol. Being mixed with Aliquat336-SCN and an acidic catalyst, the sol-state precursor slowly gelled to give an Aliquat336-SCN-containing membrane. Tributylphosphate (TBP) was used as a plasticizer. Electrochemical performances of the sol-gel membrane-based electrodes were compared to those of Aliquat336-SCN-based poly(vinyl chloride)(PVC) membrane electrodes. Membranes with an optimum ratio of Aliquat336-SCN: sol-gel precursor (1.0: 9.1 by weight) showed very stable baseline potentials. On the 7th working day, an average response slope toward thiocyanate was approximately 56.3 mVdecade-1 in the concentration range 10-4.5 and 5x10-1 M at 20℃. Moreover, selectivity toward thiocyanate over salicylate and other lipophilic anions was significantly improved, deviating from the Hofmeister selectivity pattern which is observed in most dissociated ion-exchanger-based potentiometric membrane sensors. The selectivity coefficients measured by the separate solution method in 0.05 M MES buffer, pH 5.5, were log kpotthiocyanate, chloride = - 2.3, log kpotthiocyanate, salicylate = - 0.6, and log kpotthiocyanate, perchlorate = - 0.1. Keywords: Anion-selective membrane electrode, Sol-gel method, Thiocyanate
E-mail kngyeom0730@naver.com