Stromloser Ionentransport und Potentiometrie an Membranen mit Chromoionophoren für Li⁺und UO

Abstract

Non-macrocyclic ionophores for Li+ and UO:+ have been substituted with a diphenylmaleimide unit. In membranes the obtained chromoionophores induce the same ion-selectivity and ion-transport behavior as the unsubstituted ligands.HELVETICACHIWCA A c i .~-V o I . 6 6 .Fasc.4(1983)-Nr. 108

Carrier-Based Ion-Selective Electrodes and Bulk Optodes. 2. Ionophores for Potentiometric and Optical Sensors

“…The first Li + ionophores for ISEs were obtained by increasing the number of carbon atoms between the ether oxygens of 3,6-dioxaoctanoic diamides, which were known to induce Ca 2+ selectivity ( Li + -1 , log (SSM): Na + , −1.3; K + , −2.1; NH 4 + , −1.3; Ca 2+ , −3.3; Mg 2+ , −3.7; TEHP). , They soon found an application in microelectrodes and became commercially available. , Over the years, a large number of diamides were investigated, with variations in the backbone connecting the two amide groups and the substituents on the amide nitrogens. Improvements were obtained by using the more rigid, oxygen-free backbone provided by cis -cyclohexane-1,2-dicarboxamide. , In subsequent studies, the substituents of the amide groups were varied, demonstrating their large influence on the selectivity . With ETH 1810 ( Li + -2 ; log P TLC ≈ 7.3) 48 it became possible to determine Li + in blood within the clinically relevant activity range by making calibrations in LiCl solutions with a constant background of NaCl, KCl, CaCl 2 , and MgCl 2 (log (SSM): −2.3; (FIM): −2.5; oNPOE, KTpClPB). , The membrane plasticizer used for this electrode (oNPOE) leads unfortunately to longer response times and a shorter membrane lifetime.…”

“…Very different from the above-mentioned ionophores but again in similarity to corresponding Ca 2+ ionophores are diamides that were reported as UO 2 2+ carriers. Within a series of such compounds, UO 2 2+ -4 (ETH 295) was found to give the most selective electrodes, responding with a slope typical for the monovalent UO 2 OH + (log (SSM): Ag + , −2.5; Ca 2+ , <−4.1; Cu 2+ , <−4.0; 1-chloronaphthalene; HNO 3 , pH 3, log referring to a monovalent uranyl species, which was suggested to be most likely UO 2 OH + ). , The authors claimed to have found no ion that poisoned the electrode. Fears reported elsewhere that Fe(II) or Fe(III) might poison the electrode are probably not justified as the same ionophore was successfully used for an UO 2 2+ optode with a completely reversible response to these interfering ions .…”

“…Improvements were obtained by using the more rigid, oxygen-free backbone provided by cis-cyclohexane-1,2-dicarboxamide. 113,114 In subsequent studies, the substituents of the amide groups were varied, demonstrating their large influence on the selectivity. 115 With ETH 1810 (Li + -2; log P TLC ≈ 7.3) 48 it became possible to deter-mine Li + in blood within the clinically relevant activity range by making calibrations in LiCl solutions with a constant background of NaCl, KCl, CaCl 2 , and MgCl 2 (log K Li,Na pot (SSM): -2.3; (FIM): -2.5; oNPOE, KTpClPB).…”

Modeling of Divalent/Monovalent Ion Selectivity of Ion-Exchanger-Based Solvent Polymeric Membranes Doped with Coexchanger

“…For our simulations, the values assumed were k i = 10 -5 , k j = 10 -4 . Diffusion coefficients D in solvent polymeric membranes vary in the range 10 -9 to 10 -7 cm 2 /s. − For D + and D - , the values used were in the range of 10 -9 to 10 -8 cm 2 /s, producing τ ≈ 0.1 if D + = 10 -8 and D - = 10 -9 , τ = 0.5 if D + = D - = 10 -8 , and τ ≈ 0.9 if D + = 10 -9 , D - = 10 -8 , where τ = D - /( D + + D - ). The value of was always 0.01 M, a typical level for charged ionophores.…”