Analytical Sciences

Abstract − Analytical Sciences, 22(10), 1327 (2006).

Triethylene Glycol Ether End-grafted Carbosilane Dendrimer: A Potential Ionophore for Potassium Ion Recognition
Sudeshna CHANDRA, Roy BUSCHBECK, and Heinrich LANG
Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Lehrstuhl Anorganische Chemie, Straβe der Nationen 62, 09111 Chemnitz, Germany
The performance of a newly synthesized carbosilane dendrimer bearing four triethylene glycol ether (TEG) units, Si(CH2CH2CH2Si(Me)2CH2CH2CH2(OCH2CH2)3Me)4 (1), as ionophores in ion-selective electrodes has been investigated. Optimization of the plasticized polyvinyl chloride membrane composition has produced electrodes that exhibit a Nernstian response for potassium ions. The best general characteristics exhibited by the electrodes were found when the membrane composition ratio of DPE:1:NaTPB:PVC 60:3:2:35 (wt%) was used. The response of the electrode was linear with a Nernstian slope of 58.3 mV/decade over the K+ ion concentration range of 1.9 × 10-7 to 1.0 × 10-1 M with a detection limit of 3.1 × 10-7 M. The response time to achieve a 95% steady potential for the K+ concentration ranging from 1.0 × 10-1 to 1.0 × 10-8 M was less than 10 s, and it was found that the electrode is suitable for use within a pH range of 5.5 - 8.5. The selectivity coefficients (log KK+,Mn+Pot), which were determined by the fixed interference method, showed good selectivity for K+ against most of the interfering cations. The influence of this selective ion-binding behavior using electrospray ionization time-of-flight (ESI-TOF) mass spectrometric studies is discussed.