Synthesis and characterization of covalently immobilized bis-crown ether based potassium ionophore

The synthesis of a novel covalently immobilized crown ether based potassium ionophore is presented. Apart from previously proposed methods for the preparation of PVC linked ionophores based on the chemical modification of functionalized PVC polymers, the hereby proposed procedure involves the direct copolymerization of a suitable derivative of the bis-crown ether type potassium ionophore (BME 44) and vinyl chloride monomer. The analytical performance of the potentiometric ion selective electrodes incorporating the PVC bound ionophore were optimized and determined. Compared with electrodes based on other bis-crown ether type immobilized potassium selective ionophores a slightly improved logK(K, Na)(Pot) and a longer lifetime was found. Spectral imaging and chronoamperometry were used to study the mobility of different bis-crown ether derivatives in plasticized PVC membranes.     

Studies on bis(crown ether)-based ion-selective electrodes for the potentiometric determination of sodium and potassium in serum

Bis(crown ether)-based ion-selective electrodes for sodium and potassium are described, based on the bis[(12-crown-4)-2-ylmethyl]-2-dodecyl-2-methyl malonate sensor(I) for sodium and the bis[(benzo-15-crown-5)-15-ylmethyl] pimelate sensor(II) for potassium. The best results were obtained when the sensors were used in association with 2-nitrophenyl octyl ether as plasticising solvent mediator and potassium tetrakis(4-chlorophenyl)borate as anion excluder in poly(vinyl chloride) matrices. Electrode slopes were near-Nernstian, with detection limits of less than 10(-5) M. The electrode features are compared with those of a sodium glass membrane electrode, for sensor I, and with a valinomycin-based potassium electrode, for sensor II. The electrodes are also discussed in relation to others reported for sensors I and II and are shown to be superior. However, although the electrodes described offer promising alternatives to glass electrodes for sodium and valinomycin electrodes for potassium, data for sodium and potassium measurements in blood serum indicate a need for further research in order to improve the correlation with flame photometric measurements.     

Potassium-selective PVC membrane electrodes based on bis- and poly(crown ether)s

Potassium-selective PVC membrane electrodes based on bis- and poly (crown ether)s containing benzo-15-crown-5 moiety as neutral carrier were prepared and selectivity coefficients for various monovalent ions were measured in order to elucidate the effect of complexing property of these crown ether derivatives on the electrode response. In the preference for potassium over sodium of the electrodes, these bis- and poly (crown ether)s were found to exceed the corresponding monocyclic crown ether considerably, which reflects the easy complexation of stable 2:1 complexes of crown ether ring and ion, derived from the cooperative effect of two adjacent crown ether rings.     

Hyamine 1622 - Selective PVC Membrane Electrodes Based on bis (Crown Ether)s

Abstract

Hyamine 1622 - selective PVC membrane electrodes based on bis (crown ether)s containing the benzo - 18 - crown - 6 moiety were prepared, using o - nitrophenyloctylether (NPOE) or dipentylphthalate (DPP) as the plasticizer of the PVC membrane. Selectivity coefficients for various interfering ions (inorganic and organic cations), were determined by the mixed solution method. The selectivity of the respective electrodes was found to be affected by the kind of plasticizer employed, and NPOE seemed to be a more suitable plasticizer than DPP. The NPOE electrode system based on the bis (crown ether) that has 11 atoms between the two benzo-18-crown-6 moieties offers the advantage of greater selectivity. The electrodes show excellent electrode properties, and the electrode response was stable in a wide pH range.     

Schiff碱型和仲胺型双冠醚II: 用双冠醚作载体的PVC膜钾离子选择性电极

用六个含二个苯并-15-冠-5单元的席夫碱型和仲胺型新型双冠醚作载体制备了钾离子选择性PVC膜电极,并研究了它们的电极行为,这些电极对所有的其它碱金属和碱土金属离子展现出显著的钾离子选择性,可期望有一定的应用价值.     

Molecular structure of 2-aminoethyl o-nitrophenyl ether

Conclusions The o-nitrophenyl ether of aminoethanol in the crystal has gauche conformation for the Ar-O-C-C fragment and trans conformation of the O-C-C-N fragment. The atoms of the aromatic ring, nitro group, and ether oxygen are located in a single plane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2478–2481, November, 1987.     

Potentiometric Selectivities of Dibenzo-16-crown-5 Compounds for Alkali and Alkaline Earth Metal Cations and Ammonium Ions

Potentiometric selectivities toward alkali and alkaline earth metal cations and ammonium ions are utilized to probe the complexation of these cationic species by dibenzo-16-crown-5 lariat ethers. Attachment of one or two pendant groups to the central carbon of the three-carbon bridge in dibenzo-16-crown-5 markedly alters the potentiometric responses of the ionophores when incorporated in solvent polymeric membrane electrodes. Results obtained for dibenzo-16-crown-5 compounds with coordinating side arms containing ether, carboxylic acid, ester, and amide groups provide insight into the role of the side arm in metal ion complexation by lariat ether compounds.     

The synthesis of bis(benzo-crown ether)s and their incorporation into potassium-selective PVC membrane electrodes

Five bis(benzo-15-crown-5) derivatives connected with different bridge chains were synthesized as neutral carriers in K⁺-selective electrodes. Potassium ion-selective PVC membrane electrodes based on these bis(crown ether)s were prepared using dibutyl phthalate (DBP) and dioctyl phthalate (DOP) as plasticizers of the PVC membrane. The selectivity coefficients (K _M ⁿ⁺:K _K+) for various alkali and alkaline-earth metal ions were measured. The electrodes based on the bis(crown ether)s are more selective for K⁺ than those based on monomeric crown ethers. The selectivity of one of the prepared potassium selective electrodes was higher than that of the electrode based on valinomycin and three of them were stable over a wide pH range.     

The Synthesis of Styrene/4'-vinyl-benzo-24-crown-8 Copolymer and Its Use in Potassium-Ion Selective Electrodes

A synthetic procedure has been developed for the preparation of styrene/4'-vinyl-benzo-24-crown-8 copolymer (SPV-B24C8). The resulting copolymer was used as a membrane carrier to construct a K+ ion-selective electrode. The electrode exhibits a Nernstian response for K+ ions over a wide concentration range. The nature of the plasticizer, the additive, the concentration of internal solutions in the electrodes and the composition of the membrane were investigated. The performance of the electrode in terms of electrode reproducibility, response stability and regeneration was also studied. The selectivity coefficients of the electrode for potential interferents including alkali, alkaline earth, some transition and heavy metal ions were found to be in the order of 10-3 or less. The electrode was successfully used for the determination of potassium ion in blood serum.     

Probing ionophore selectivity in argon-tagged hydrated alkali metal ion-crown ether systems

Crown ethers are an important family of compounds that are closely related to naturally occurring ionophores. Thus, crown ethers are useful in modeling the size-selective behavior of ionophores. Using a combination of infrared predissociation spectroscopy and density functional theory calculations, we have investigated M(+)(18-crown-6 ether)(H(2)O)(1-4) Ar complexes, where M = Li, Na, K, Rb and Cs in the gas phase. The argon-tagging technique was used to lower the internal energies (effective temperatures ~100 K), yielding well-resolved spectra in the OH stretching region for systems containing up to three waters. Spectral changes were monitored as both the size of the ion and degree of hydration were varied. While there is not a particular spectroscopic signature of gas-phase selectivity reported in this work, the unique role that K(+) plays in the systems studied, as a "bridge" between the smaller and larger alkali metal ions, is consistent with the well-known special affinity for K(+) by 18-crown-6 ether in the aqueous phase.     

In vivo measurements with a potassium ion-selective microelectrode based on a new bis(crown ether)

Potassium ion-selective microelectrodes with a tip diameter of 10 μm are described. The ionophore used is 2,2′-bis[3,4-(15-crown-5)-2-nitrophenylcarbamoxymethyl] tetradecane in a conventional mixture with sodium tetraphenylborate, an ether and PVC. The electrode provides Nernstian response over the range 10^?5?10^?1 M potassium activity. Its selectivity is shown to be similar to that of a valinomycin-based microelectrode. After the electrode has aged for 24 h, the 95% response time at the 10^?3 M potassium ion level is 2.0 ± 0.5 s. The applicability of the bis(crown ether) electrode for measurements in vivo is proved by monitoring the changes in potassium activity in different areas of the brain of anaesthetized rats after administration of veratrine.     

Triethylene glycol ether end-grafted carbosilane dendrimer: a potential ionophore for potassium ion recognition.

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 1.9x10(-7) to 1.0x10(-1) M with a detection limit of 3.1x10(-7) M. The response time to achieve a 95% steady potential for the K+ concentration ranging from 1.0x10(-1) to 1.0x10(-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 KPotK+,Mn+)), 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.     

Flow injection study of the potentiometric lithium selectivity of cyclic dioxadiamides containing oxygen and nitrogen atoms

Summary Four 15-membered ring cyclic compounds with two oxygen and two nitrogen atoms incorporated in the ring were prepared and evaluated as neutral carriers in lithium ion-selective electrodes. These ionophores, along with potassium tetrakis (p-chlorophenyl)borate and o-nitrophenyloctyl ether (NPOE), were included in the PVC matrix that coated the tip of a silver-wire electrode. The potentiometric selectivities of the electrodes towards lithium over sodium, potassium, calcium and magnesium were determined. Selectivity coefficients, K _{Li, Na} ^pot ., as low as 9.5×10^–3 were obtained and smaller coefficients for other metals, K _{Li, M} ^pot ., were found. A calibration curve for lithium in the presence of 140 mmol/l sodium, with a linear portion having a slope of 51 mV/decade, was obtained. The effect of incorporating 1% trioctylphosphine oxide (TOPO) in the electrodes was studied. Comparison with the results obtained with 15-crown-4-ethers is made.

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Fließinjektionsuntersuchung der potentiometrischen Lithium-Selektivität von cyclischen Dioxadiamiden, die Sauerstoff- und Stickstoff-Atome enthalten

     

New cesium ion-selective electrodes based on anilino-(1,3-dioxo-2-indanylidene) acetonitrile derivatives

Cesium ion-selective PVC membrane electrodes based on anilino-(1,3-dioxo-2-indanylidene) acetonitrile derivatives as a novel class of neutral ionophores were examined. The ionophores were p-methoxyanilino-(1,3-dioxo-2-indanylidene) acetonitrile, p-methylanilino-(1,3-dioxo-2-indanylidene) acetonitrile and p-N,N-dimethylanilino-(1,3-dioxo-2-indanylidene) acetonitrile. The anilino-(1,3-dioxo-2-indanylidene) acetonitrile proved to work well with cesium, the corresponding electrodes display a response to this ion. The most favourable ionophore was p-methoxyanilino-(1,3-dioxo-2-indanylidene) acetonitrile, especially when the secondary ion exchanger potassium tetrakis (4-chlorophenyl) borate was incorporated in 2-nitrophenyl octyl ether for ion-selective electrode membrane construction. The response function was linear within the concentration range 10(-1)-2.5x10(-5) mol l(-1) and the slope was 52 mV decade(-1). The detection limit remained at 6.3x10(-6) mol(-1). The selectivity and response time of the electrode was studied and it was found that the electrode exhibited good selectivity for cesium over alkali, alkaline earth and some transition metal ions. The electrode response was stable over a wide pH range. The lifetime of the electrode was about 1 month.     

Synthesis and potentiometric selectivity study of new spiro-14-crown-4 derivatives

Abstract

Four new compounds with 14-crown-4 attached to spirocyclopentane or spirocyclohexane were synthesized and tested for potentiometric selectivity for lithium ion in polyvinyl chloride membrane electrodes. Four plasticizers were studied and the addition of tri-octylphosphine oxide (TOPO) was investigated. One ionophore exhibited a sodium/lithium selectivity, K^pot _Li,Na by the matched potential method of 0.0028 in the presence of 1% TOPO, using o-nitro-phenylphenyl ether as plasticizer. Selectivities are reported for sodium, potassium, nickel, cobalt, barium and calcium.     

Sulfonated poly(ether ether ketone) as an alternative charged material to poly(vinyl chloride) in the design of ion-selective electrodes

To date, poly(vinyl chloride) (PVC) is the most used polymer in the design of ion selective electrode (ISE) membranes. This paper is focused on the use of sulfonated poly(ether ether ketone) (SPEEK) as an alternative material to PVC for the design of ISEs. SPEEK of the desired degree of sulfonation is synthesized from poly(ether ether ketone) (PEEK). An NH₄⁺-ISE has been chosen as a model electrode to study the efficiency of SPEEK as polymer matrix of the membrane. The material was evaluated in ionophore free ion exchanger membranes as well as in ion-selective electrodes membranes containing nonactine as ionophore. Analytical performance parameters of the prepared electrodes were evaluated. The electrodes show a slope between 50 and 60 mV dec⁻¹ depending on both the calibration medium and the membrane composition. A linear range of response between 10⁻⁴ and 1.0 M and a lifetime of 1-2 months were obtained. The interferences of cations such us Ca²⁺, Na⁺, Li⁺ and K⁺ over the prepared ISEs are studied as well. Although the plasticizer in the SPEEK based membrane matrix is not necessary, its presence improves the sensibility. This makes SPEEK a good potential choice over alternative membrane matrices reported in the literature and a promising platform for the establishment of membrane components.     

Reversible electrochemical oxidation of (CH)x films

Thallium(I)-selective PVC membrane electrodes based on bis(crown ether)s containing benzo-15-crown-5 moiety were prepared, using o-nitrophenyloctylether(NPOE) or dipentylphthalate(DPP) as the plasticizer of the PVC membrane. Selectivity coefficients for various alkali and alkaline earth metal ions, k_TIM, were sufficiently small, and were compared with those of the corresponding monocyclic analog and valinomycin. These electrodes show excellent electrode properties, and the electrode response was stable in a wide pH range.     

Coated-wire electrodes containing polymer immobilized ionophores blended with poly(vinyl chloride)

Polymers containing covalently attached 18-crown-6 or 2.2.2 cryptand units were incorporated into plasticized PVC membranes and the composite membranes were examined as potassium ion sensor elements. Ionophores were linked to carboxy-PVC and to poly(acrylic acid) via amide linkages to an alkyl spacer unit. Coated-wire electrodes (CWEs) from the immobilized ionophores gave acceptable responses, but conventional ion-selective membrane electrodes (ISEs) prepared by solvent casting were inactive. Dip-cast membranes did give active ISEs. Potassium electrode performance was independent of the loading of the ionophore within the acrylate support polymer, but depended upon the spacer length. Ion selectivity varied with the ionophore loading within the support polymer. Selectivity is a composite of the ionophore selectivity and ion-exchange interactions with the acrylate backbone, giving selectivities akin to carboxylate substituted crown ethers, notably enhanced monovalent/divalent ion discrimination relative to the ionophore in solution. Polymer immobilization extended the lifetime of active electrodes.     

Comparative performance of 14-crown-4 derivatives as lithium-selective electrodes

A series of neutral ionophore-based lithium-selective liquid-membrane electrodes have been prepared and the electrode performance compared with similar electrodes based on the lithium ionophores ETH 1810-ortho-nitrophenyl octyl ether (oNPOE) and ETH 2137-bis(1-butylpentyl) adipate (BBPA). By using a diamide substituted 14-crown-4 macrocycle, selectivities for Li+ in the presence of Na+ of log kpotLi,Na = -3.25 and -2.92 were obtained for diisobutylamide-oNPOE and di-n-butylamide-oNPOE derivatives. The di-n-butylamide-oNPOE based electrode functioned satisfactorily in serum, exhibiting a fast response time (10-15 s), an acceptable lifetime of 50 d and minimal protein interference.     

冠醚载体离子电极的选择特性研究

阴离子选择电极选择性系数随干扰离子r_j/z_j的变化规律已有报道,但冠醚为中性载体的金属离子电极的选择性系数规律未见报道。本文采用不同桥间结构的11种苯并双冠醚作为中性载体,从钾电极出发探讨了不同冠醚电极选择性系数与干扰离子r_j/z_j间的关系;并以4种烃型双冠醚为中性载体,分别考察了它们对Li~+、Rb~+、Cs~+、Ag~+、Ba~(2+)离子的响应规律。 1 实验部分