Neutral Carrier-Type Ion Sensors Based on Sol−Gel-Derived Membranes Incorporating a Bis(crown ether) Derivative by Covalent Bonding

Abstract

Sol-gel-derived membranes incorporating crown ether neutral carriers by covalent bonding have been designed for durable, nontoxic neutral carrier-type ion sensors by sol-gel processing using tetraethoxysilane, diethoxydimethylsilane, and their corresponding alkoxysilylated neutral carriers. A tetraphenylborate anion was also bound chemically to the neutral carrier-type sol-gel-derived membranes for suppressing anion interference and membrane impedance. Ion-sensitive field effect transistors (ISFETs) based on the sol-gel-derived membranes modified chemically by crown ether derivatives, such as 16-crown-5 and bis(12-crown-4) derivatives, showed high performance, high sensitivity in wide cation activity ranges, short response time, and high electrode durability. Specifically, high ion selectivities of practical use in biological systems were attained in the sodium ISFETs based on the chemically modified bis(12-crown-4), which has been successfully applied to sodium assay in blood sera.

A two-component polymeric optode membrane based on a multifunctional ionic liquid

“…UV/VIS absorption data for the purified IL's were performed using a µQuant® plate well reader by adding 500 µL of metal salt solution (if used) to 500 µL of [P 6,6,6,14 ][DCA]. Vibrational spectra were obtained using a Perkin Elmer Spectrum GX FT-IR System® and Perkin Elmer Raman Station 400F®.…”

“…Both PVC and [P 6,6,6,14 ][DCA] (1:2 (w/w)) were added to 2 ml THF and stirred until dissolved. The resulting solution was then poured into a glass ring on a glass slide held together by rubber bands.…”

“…There has been great interest in simplifying these chemical sensor mixtures , for example, through the development of plasticizer-free matrices, 3, 4 covalent attachment of active sensing components to polymer backbone 3,5,6 , and improving the lipophilicity of sensing components [7][8][9] .…”

Peer Reviewed: Sol–Gels and Electrochemistry: Research at the Intersection.

“…The resultant sol can be poured on a flat surface and then cut into membranes to mount on electrodes, or it can be spin-cast on the surface of an ionsensitive field-effect transistor. These materials have good selectivity and biocompatibility, particularly relative to commonly used poly(vinyl chloride) membranes (26).…”

Simple, Robust, and Plasticizer-Free Iodide-Selective Sensor Based on Copolymerized Triazole-Based Ionic Liquid

“…17 Kimura reported on the covalent immobilization of anionic lipophilic salts (tetradecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride) into sol-gel based membranes. 18 Other attempts to improve the robustness and sensing properties of ISEs were aimed towards finding appropriate replacement to the conventional plasticizers such as dioctyl sebacate (DOS) or 2-nitrophenyl octyl ether (NPOE) since the nature of the plasticizer plays a pivotal role in the analytical performance of polymer based sensors. 19 Here, the authors have used polymeric plasticizer (polyester sebacate (PES) to be more precise) and demonstrated that polymeric nature of the plasticizer increases retention of membrane components thus resulting in robust membranes exhibiting significantly longer life-times relative to traditional ones.…”