Chemical stability and application of a fluorophilic tetraalkylphosphonium salt in fluorous membrane anion-selective electrodes

Chen, Li D.; Mandal, Debaprasad; Gladysz, J. A.; Bühlmann, Philippe

doi:10.1039/b9nj00696f

Cited by 19 publications

(21 citation statements)

References 47 publications

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“…Previous work from our group has shown the benefits of using fluorous sensing membranes that consist of fluorous plasticized polymer matrixes doped with fluorophilic ionophores, ionic sites, and electrolytes . We found that fluorous systems exhibit substantially improved ion selectivities as compared to non‐fluorous ISE membranes, which has also resulted in remarkably low detection limits .…”

Section: Introductionmentioning

confidence: 72%

Cleaning of pH Selective Electrodes with Ionophore‐doped Fluorous Membranes in NaOH Solution at 90 °C

et al. 2017

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This work demonstrates the remarkable stability of fluorous ion‐selective electrode (ISE) membranes by exposing them to cleaning‐in‐place treatments (CIP) as they are used in many industrial processes. The sensing membranes consisted of Teflon AF2400 plasticized with a linear perfluoropolyether and doped with ionic sites and a H+ ionophore (i. e., tris[3‐(perfluorooctyl)propyl]amine, 1, or tris[3‐(perfluorooctyl)pentyl]amine, 2). To mimic a typical CIP treatment, the electrodes were repeatedly exposed for 30 min to a 3.0 % NaOH solution at 90 °C (pH 12.7). ISE membranes doped with the less strongly H+ binding ionophore 1 started to show reduced potentiometric response slopes and increased resistances after one exposure for 30 min to hot 3.0 % NaOH solution. No decomposition of the ionic sites and ionophore 1 at 90 °C was evident by 1H NMR spectroscopy, suggesting that the performance of membranes doped with 1 was compromised primarily by leaching of the negatively charged ionic sites along with H+ into the hot caustic solution. In contrast, even after ten exposures to hot 3.0 % NaOH for a cumulative 5 h at 90 °C, the fluorous sensing membranes doped with the more strongly H+ binding ionophore 2 still showed the ability to respond with a theoretical (Nernstian) slope up to pH 12. Addition of the fluorophilic electrolyte salt methyltris[3‐(perfluorooctyl)propyl]ammonium tetrakis[3, 5‐bis(perfluorohexyl)phenyl]borate reduced the membrane resistance by an order of magnitude.

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Section: Introductionmentioning

confidence: 72%

Cleaning of pH Selective Electrodes with Ionophore‐doped Fluorous Membranes in NaOH Solution at 90 °C

et al. 2017

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“…The fluorophilic salts bis(tris[(perfluorohexyl)propyl]phosphine)iminium chloride ( 1 ) and sodium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate ( 2 ) were used to provide for cationic and anionic sites, respectively. In comparison to salts of fluorophilic cations used in previous potentiometric studies, the bis(triphenylphosphoranylidene)ammonium cation of 1 has the advantage of a higher chemical stability in the presence of HO – than previously reported fluorophilic phosphonium cations and does not bind coordinatively to analyte anions. Fluorous membranes doped with cationic site 1 did not show any sign of deterioration even when exposed to strongly alkaline solutions, such as 0.1 M NaOH, and exhibited no more interference from OH – than expected for a nonspecific ionophore-free ion exchanger membrane with Hofmeister selectivity (see also p 1595 of ref ).…”

Section: Resultsmentioning

confidence: 91%

Potentiometric Sensors Based on Fluorous Membranes Doped with Highly Selective Ionophores for Carbonate

et al. 2011

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Manganese(III) complexes of three fluorophilic salen derivatives were used to prepare ion-selective electrodes (ISEs) with ionophore-doped fluorous sensing membranes. Because of their extremely low polarity and polarizability, fluorous media are not only chemically very inert but also solvate potentially interfering ions poorly, resulting in a much improved discrimination of such ions. Indeed, the new ISEs exhibited selectivities for CO32− that exceed those of previously reported ISEs based on non-fluorous membranes by several orders of magnitude. In particular, the interference from chloride and salicylate was reduced by two and six orders of magnitude, respectively. To achieve this, the selectivities of these ISEs were fine-tuned by addition of non-coordinating hydrophobic ions (i.e., ionic sites) into the sensing membranes. Stability constants of the anion–ionophore complexes were determined from the dependence of the potentiometric selectivities on the charge sign of the ionic sites and the molar ratio of ionic sites and the ionophore. For this purpose, a previously introduced fluorophilic tetraphenylborate and a novel fluorophilic cation with a bis(triphenylphosphoranylidene)ammonium group, (Rf6(CH2)3)3PN+P(Rf6(CH2)3)3, were utilized. The optimum CO32− selectivities were found for sensing membranes composed of anionic sites and ionophore in a 1:4 molar ratio, which results in the formation of 2:1 complexes with CO32− with stability constants up to 4.1 × 1015. As predicted by established theory, the site-to-ionophore ratios that provide optimum potentiometric selectivity depend on the stoichiometries of the complexes of both the primary and the interfering ions. However, the ionophores used in this study give examples of charges and stoichiometries previously neither explicitly predicted by theory nor shown by experiment. The exceptional selectivity of fluorous membranes doped with these carbonate ionophores suggests their use not only for potentiometric sensing but also for other types of sensors, such as the selective separation of carbonate from other anions and the sequestration of carbon dioxide.

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“…[39] Although it could be argued that the tetran-butylammonium is not the usual counterion to appear in Nature or bio-related applications, it is noteworthy that the sodium or any other salts may also be used either directly, as shown on the differentiation urine samples based on electrolyte content or in conjunction with tetrabutylammonium (TBA) perchlorate additive that acts as an ion-exchanger commonly used in ion-selective electrodes for anions. [35,44] Each of the individual polymerprobe sensors displays a different response to the anions. This is due to the probe-anion interaction as well as to different distribution of hydrophilic and hydrophobic domains within PUs, a feature that is easy to adjust by using a different proportion of comonomers during the polymer synthesis.…”

Section: Resultsmentioning

confidence: 99%

Leveraging Material Properties in Fluorescence Anion Sensor Arrays: A General Approach

Anzenbacher

Liu

Palacios

et al. 2013

Chemistry A European J

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As the demand for probes suitable for sensor development increases, investigation of approaches that utilize known successful receptors gains in general importance. This study describes a two-prong approach that can be used as a guide to developing sensors from known receptors. First, the conversion of a simple receptor, calix[4]pyrrole, into a fluorescent probe to establish a ratiometric signal is described. Secondly, the sensors that employ an output from a single ratiometric calix[4]pyrrole probe are fabricated by using poly(ether-urethane) hydrogel copolymers. These hydrogels are designed to absorb, internalize and transport aqueous electrolytes. A sensor array of ten different poly(ether-urethane) matrices with varying comonomer proportions were doped with a single probe and were exposed to eight different anions: acetate, benzoate, fluoride, chloride, phosphate, pyrophosphate, hydrogen sulfide, and cyanide, eight urine samples and anti-inflammatory drugs (NSAIDs). The poly(ether-urethane) matrices comprise different proportions of anion-binding urethane moieties and different hydrophilicity given by the ratio between ethylene glycol ether and butylene glycol ether. This diversity in the hydration behavior provides different environment polarity, in which the recognition and self-assembly processes display enough diverse behavior to allow for unique response of the probe to the analytes. Furthermore, a single probe is shown to recognize eight different aqueous anions and eight urine samples when embedded in ten different polyurethanes in an array that displays 100 % classification accuracy. To demonstrate the potential of the concept for quantitative studies, an estimation of non-steroidal anti-inflammatory drugs ibuprofen and diclofenac in water and in saliva was performed. A limit of detection of 0.1 ppm and a dynamic range of 0.1-0.6 and 0.05-60 ppm was observed, respectively. Given the general difficulty of chemosensors to recognize aqueous anions, the fact that one probe recognizes eight different analytes attests to an enormous effect of the polymer environment on the recognition process. This method could be used to generate a variety of sensor arrays for various analyses including species that are difficult to recognize, such as small-molecule- and inorganic anions.

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Chemical stability and application of a fluorophilic tetraalkylphosphonium salt in fluorous membrane anion-selective electrodes

Cited by 19 publications

References 47 publications

Cleaning of pH Selective Electrodes with Ionophore‐doped Fluorous Membranes in NaOH Solution at 90 °C

Cleaning of pH Selective Electrodes with Ionophore‐doped Fluorous Membranes in NaOH Solution at 90 °C

Potentiometric Sensors Based on Fluorous Membranes Doped with Highly Selective Ionophores for Carbonate

Leveraging Material Properties in Fluorescence Anion Sensor Arrays: A General Approach

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