Pair Extraction Research Articles

Role of hydrophobic counteranions in the ion pair extraction of lanthanides(iii) with an electrically neutral extractant

The effect of a hydrophobic and weakly coordinate bonding anion, tetrakis[3,5-bis(trifluoromethyl)phenyl] borate (TFPB−), on the extraction of lanthanides(III) with an electrically neutral extractant, tetraoctyldiglycolamide (TODGA), has been examined. By adding H+TFPB−, the extraction of these metal ions is greatly enhanced; besides, the selectivity is also much improved. The metal extraction with TFPB− working as a counteranion is, formally, in a category of ion pair extraction, involving ion exchange of H+ paired with TFPB− for the metal ion. However, with such a hydrophobic anion, a peculiar phenomenon, which has never been seen in traditional ion pair extraction, occurs, i.e., the distribution ratio of a lanthanide(III) is only slightly dependent on the concentration of TODGA over a wide range, at least, from 5 × 10−4 to 0.4 M, or rather, it is somewhat decreased at high TODGA concentrations. This is, seemingly, against the general rule of solvent extraction, but can be explained coherently from the viewpoint of chemical equilibrium. Two ion pair extraction equilibria, one of which has the opposite sign to the other in the dependence of the distribution ratio of the metal on the concentration of TODGA, are postulated. The slight change in the metal distribution ratio over the wide range of the TODGA concentration is understood as a “buffer zone” occurring between the two different ion pair extraction equilibria with TFPB−.

A mechanistic study on ion pair extraction using single microdroplet injection and microelectrochemical techniques

Ion pair extraction from water into oil in a (ferrocenylmethyl)trimethylammonium bromide (FcTMABr)–sodium hexafluorophosphate (NaPF6) system was studied kinetically by injection and manipulation of a single oil droplet of 10−8 cm3 and electrochemistry of the single droplet contacting a microelectrode. The FcTMA+ concentration extracted into the oil phase at the distribution equilibrium was dependent on the FcTMABr, NaPF6, and NaCl concentrations in the water phase. The initial rate of the ion pair extraction was directly proportional to the FcTMABr concentration in water, while it was independent of the NaPF6 and NaCl concentrations in water. These results indicate that the ion pair extraction rate is governed by the ion transfer of FcTMA+ from water into the droplet, maintaining the electroneutrality in the droplet by the PF6− transfer.

Automatic Extraction of Translational Japanese-KATAKANA and English Word Pairs from Bilingual Corpora

A method to automatically extract translational Japanese-KATAKANA and English word pairs from bilingual corpora is proposed. The method applies all the existing back-transliteration rules to each mora unit in a KATAKANA word, and extracts the English word which matches or partially matches one of these back-transliteration candidates as translation. The mora unit is a Japanese syllable unit and one Katakana character often corresponds to one mora. For instance, if we have in the Japanese part of a bilingual corpora, we generate such back-transliteration candidates as , , ,… and identify similar words from the English part of the corpora. The method performs reasonably well, achieving 80%–100% precision at 75% recall against the eight corpora we used for evaluation.

Measurement of bisphenol A in human serum by gas chromatography/mass spectrometry

The purpose of this study is to establish an easy and accurate method for the determination of bisphenol A (BPA) in the human serum. The samples were applied to the C 18 solid phase extraction (SPE) column for clean up of samples. The BPA is conjugated with tetrabutylammonium hydrogen sulfate as the counter ion in alkali solution. The ion paired BPA is moves from the aqueous phase to the organic phase as an ion paired extraction. BPA extracted from human serum were derivatized with pentafluorobenzyl bromide (PFBBr). The derivative was analyzed by gas chromatography (GC)/mass spectrometry (MS) using negative chemical ionization (NCI). The instrumental detection limit of BPA was 5 pg/ml (10 fg). The instrumental response between 0.01 and 100 pg/ml of BPA standards was linear ( r 2=0.998). The recovery of BPA spiked into human serum was 101.0±4.63 (1 pg/ml) and 100.9±3.75 (10 pg/ml), respectively. The concentration of BPA in the human serum from 20 individuals was 0.54 pg/ml.

Evaluation of Gibbs free energy for the transfer of a highly hydrophilic ion from an acidic aqueous solution to an organic solution based on ion pair extraction

A method to determine the standard Gibbs free energy for the transfer, Δ G° tr, of a highly hydrophilic metal ion from an aqueous solution, W, in the presence of high concentration of H + to an organic solution, O, was proposed based on the theoretical consideration of the distribution process of ions between W and O. The usefulness of the proposed method was verified experimentally by comparing Δ G° tr of Mg 2+ determined by the method with that obtained by voltammetry for the ion transfer at the W|O interface. The O examined were nitrobenzene (NB) and 1,2-dichloroethane (DCE). By applying the proposed method, Δ G° tr of NpO 2 +, UO 2 2+, NpO 2 2+ and PuO 2 2+ from an acidic W to NB were determined.

On-Chip Integration of Neutral Ionophore-Based Ion Pair Extraction Reaction

Integration of a neutral ionophore-based ion pair extraction reaction onto a glass microchip was performed. Since the liquid microspace provides a short molecular diffusion distance and a large specific interfacial area of the liquid−liquid interface, novel attractive analytical features arise such as extremely fast ion sensing and ultrasmall reagent solution volume. In contrast to the slow response time of a standard ion optode, in which the response time is basically governed by slow diffusion of ionic species in the viscous polymer membrane, that of the on-chip ion-sensing system is clearly faster due to the short molecular diffusion distance and low viscosity of organic solution. In this case, the organic solution containing a neutral ionophore and a lipophilic pH indicator dye and the aqueous solution containing sample ion were independently introduced into microchannel to form an organic−aqueous interface. Then determination of the ion was performed by thermal lens microscopy at the downstream of th...

The effect of hydrophobic picrate on the extraction and separation of lanthanides(III) with carbamoylmethylene phosphine oxide

The effect of a hydrophobic anion, such as picrate (pic−), on the extraction and separation of Ln(III) ions with a carbamoylmethylene phosphine oxide (CMPO) from aqueous nitric acid solutions into benzene has been examined in the present study. The metal extraction with the CMPO was greatly enhanced by adding a small amount of pic−, which did not coordinate with the metal ions but only played the role of a counter-anion in the ion pair extraction. Furthermore, the separation of the Ln(III)-series was also improved, which is a great advantage of the anion effect: On the contrary, a synergism by using two extractants, both of which can coordinate with a metal ion, generally decreases such selectivity. From analyses of the distribution data of Ln(III) ions and picric acid, the mechanism of the cooperative effect was clarified. The strong cooperative effect originates from the difference in the hydrophobicity between pic− and NO3−. Indeed, the Eu(III)–CMPO complex cation paired with pic− was much less hydrated than that paired with NO3−; besides, the binding number of CMPO to the Ln(III) ions also seemed to be affected by the hydration. From these results it is concluded that the metal ions can be dehydrated by the effect of hydrophobic pic−, to a great extent, when its ion pairs are formed. This can be the origin of the great enhancement of the extractability by adding pic−. Metal dehydration can also produce the improved selectivity for the Ln(III) ions, i.e., the coordination of the CMPO can be performed more effectively with much fewer water molecules hydrated to the metal ions, and, thus, the inherent selectivity of the extractant can be exhibited more clearly. Metal dehydration can be induced under the influence of pic−, which is quite inert in coordination, electrostatic interaction, and hydration properties.

Alterations in cathepsin H activity and protein patterns in human colorectal carcinomas.

Our analyses of cathepsin H activity levels and protein forms in human colorectal cancers compared to matched control mucosa support the concept that altered proteinase expression patterns may reflect both cancer stage and site. Cathepsin H-specific activity was significantly increased in colorectal cancers compared to control mucosa (P = 0.003;n = 77). Highest specific activities and cancer/normal ratios (C/N) for activity were measured in Dukes' B and C stage carcinomas, cancers involved in local spread and invasion to lymph nodes. In contrast, cathepsin B and L activities analysed in the same paired extracts had been shown to be most frequently elevated in earlier stage carcinomas (Dukes' A and B), confirming that cathepsin H demonstrates a distinct pattern of expression during colorectal cancer progression. Although cathepsin H activities were most commonly elevated in Dukes' C cancers at all colon sites, both specific activity and C/N ratios were significantly higher for cancers of the left colon compared to other colon locations. A subset of 43 paired extracts analysed on Western blots also revealed consistent changes in cathepsin H protein forms in cancers. Normal mucosa typically showed a strong protein doublet at 31 and 29 kDa while cancers demonstrated decreased expression or total loss of the 31 kDa protein (90% of cases), equal or increased expression of the 29-kDa protein (67% of cases) and the new appearance or up-regulation of a cathepsin H band at 22 kDa (78% of cases). C/N ratios for cathepsin H enzyme activity correlated significantly with C/N ratios for the 29 kDa mature single-chain protein form (P< 0.001), with increased activity most commonly associated with elevated expression of 29-kDa cathepsin H but also with up-regulation of the 22-kDa band, suggesting a shift to more fully processed, mature active cathepsin H protein forms in cancers. Changes in cathepsin H expression were also detected by immunohistochemistry as elevated cathepsin H staining in tumour epithelial cells. © 2000 Cancer Research Campaign

Novel dual-host approach in ion pair extraction: a simple tripodal nitrate host facilitates CsNO3 transfer to 1,2-dichloroethane by a large crown ether

The readily available benzene-1,3,5-tricarboxamide 1 enhances CsNO3 extraction by tetrabenzo-24-crown-8 via hydrogen bonding to the nitrate anion, as demonstrated by NMR and electrospray ionization mass spectrometry.

Efficient Ion-Pair Extraction of Potassium Chloride from Aqueous Phase into Nitrobenzene Containing Dicyclohexyl-18-crown-6 as Cation Binder and Diphenylthiourea as Anion Binder

In combination with an ion pair extraction of potassium salts by dicyclohexyl-18-crown-6 (DC18C6), extraction behavior of anions with a diphenylthiourea (DPTU) from aqueous phase into nitrobenzene has been examined. The extraction selectivity of potassium salts follows a Hofmeister series: NO3->Br->Cl->OAc-. The extractability of KCl by DC18C6 is significantly enhanced upon the addition of DPTU in organic solution. The slope analysis of the extraction equilibrium reveals a 1:1 complex formation between DPTU and Cl-. The hydrogen-bonding interaction of DPTU with Cl- is confirmed by the 1H NMR analysis in d5-nitrobenzene. For qualitative evaluation, solid-liquid extraction of KCl into d5- nitrobenzene containing DPTU and DC18C6 has been examined by 1H NMR analysis. Similar to the liquid-liquid extraction, an efficient synergistic effect of DPTU for the extraction of KCl is clarified.

Automatic extraction of corresponding points for the registration of medical images.

In this paper we address the problem of finding corresponding points in a reference and its subsequent image with the aim of registering the images. A whole-image-content-based automatic algorithm for extracting point pairs from 2-D monomodal medical images has been developed. The properties of point distinctiveness, point pair similarity, and point pair consistency have been incorporated into the steps which lead to the automatic extraction and weighting of point pairs. The selection of the most distinctive points of the reference image, and the search for their corresponding points in the subsequent image, have two things in common. First, the local operator by which the distinctive points are selected mimics the template matching used to find the corresponding points. Second, the same similarity measure is used for both tasks. We have applied the algorithm to a variety of computer-generated and real medical images, and have both qualitatively and quantitatively evaluated its performance. The results show that the proposed automatic algorithm for point extraction is accurate and robust and that it may significantly improve on the accuracy, reproducibility, and speed of the manual extraction of corresponding points.

イオン対抽出分配比および分配比とイオン選択性電極電位の関係の基礎電気化学的理解

Equations were derived for the quantitative expressions of distribution ratios, D, in ion pair extractions of a cation, i+, with a counter ion, x- from water, W, to organic, O, in the absence and presence of a special complexing neutral ligand, Y, in O by using standard transfer free energies of i+ and x- from W to O, ion pair formation constants of i+ with x- in W and O, the stability constant of the complex, (iYp)+, in O and the ion pair formation constant of (iYp)+ with x- in O. The D calculated by substituting the constants determined by electrochemical methods into the derived equations agreed very well with those obtained experimentally by the ion pair extraction, which means that the extraction processes assumed in the derivation of the equations have been reasonable. Distribution . ratios in ion pair extraction were connected quantitatively to the potentials, EISE, and selectivity coefficients, Kpotj, at an ion selective electrode, ISE, of liquid membrane type, taking into account that all of EISE, Kpotij and D could be expressed physicochemically by using standard Galvani potential differences (or standard free energies ) for ion transfers from W to the ISE membrane, M, or O, stability constants of complexes with a neutral ligand in M or O and formation constants of ion pairs with coexisting counter ions in M or O. Theoretical equations derived from the relations between EISE and Kpotij and D were verified experimentally.

Evaluation of distribution ratio in ion pair extraction using fundamental thermodynamic quantities

Equations were derived for the quantitative expressions of distribution ratios, D M, in ion pair extractions of a cation, M +, with a counter ion, X −, from water, W, to an organic solvent, O, in the absence and presence of a special complexing neutral ligand, L, in O by using standard transfer free energies of M + and X − from W to O, ion pair formation constants of M + with X − in W and O, the stability constant of the complex, (ML) +, in O and the ion pair formation constant of (ML) + with X − in O. The D M values calculated by substituting the constants determined by electrochemical methods into the derived equations agreed very well with those obtained experimentally by ion pair extraction, which means that the extraction processes assumed in the derivation of the equations was reasonable.

Regioselectivity in the C-alkylation of triethyl 3-methyl-4-phosphonobut-2-enoate

The reaction of triethyl 3-methyl-4-phosphonobut-2-enoate (1) with three alkyl halides AlkX (Alk=Pri, Me2CHCH2CH2, andc-C5H9; X=Br, I) in the system KOH(solid)∩DMF∩Bun4NBr at ≈20°C gives exclusively products of alkylation at C(2) with Δ2 and/or Δ3 position of the double bond. Under the same conditions, the reaction of 1 with MeI gives a mixture of products with different substitution patterns. Only the use of an ion pair extraction technique affords 2-methyl-Δ2-products selectively, albeit in rather moderate yields. The Horner—Emmons olefination of PhCHO with the resulting phosphonates gives ethyl 2-alkyl-3-methyl-5-phenylpenta-2,4-dienoates in high yields.

Extraction of Sunset Yellow and Tartrazine by Ion-pair Formation With Adogen-464 and Their Simultaneous Determination by Bivariate Calibration and Derivative Spectrophotometry

A simple extraction–spectrophotometric method for the determination of tartrazine (Tz) and Sunset Yellow (SY) in mixtures, based on the extraction of the ion pairs formed between the dyes and trioctylmethylammonium chloride (Adogen-464) into toluene, is described. With the proposed method, calibration graphs are linear up to 3.0 µg ml–1 for Tz and 3.6 µg ml–1 for SY. The bivariate calibration method was applied to the resolution of binary mixtures of the dyes and the results were compared with those given by first-derivative spectrophotometry. The methods were applied to the determination of both compounds in commercially available food products.

Simultaneous determination of the ionisation and dimerization constants and the partition and ion pair extraction coefficients for 1–8 naphtyridine derivatives

Conventional experimental studies of water/octanol partition at different pHs and concentrations were used to simultaneously evaluate (i) the true P octanol/water partition coefficient, (ii) acidity constants and (iii) extraction constants for ion pairs produced by the ions in the buffers used (phosphate ions). The studies also rejected the hypothesis that dimers are formed in the octanol phase. The method, applied to a few substituted 1,8-naphtyridine substances, used a new software whose algorithm is based on the principle of error minimisation using a simplex method. The fundamental equations used to calculate the concentration of the test species in each experimental situation (pH, concentration, phase volume ratios, counter-ions) are explained.

Coupling Ion-Pair Extraction with Adsorption for the Separation of Acidic Solutes from Water

In addition to energy considerations, the cost and potential liability for waste disposal are requiring the chemical process industries to invest in separations for waste minimization (e.g., for the recovery and recycling of reusable materials). To achieve selectivity for the adsorptive separations of acidic solutes, the authors examined the coupling of ion pair extraction with adsorption. Specifically, they used the quaternary ammonium extractant tricaprylmethylammonium chloride (Aliquat 336, Henkel), the inert solvent hexane, and a polar acrylic ester sorbent (Amberlite XAD-7, Rohm and Haas), and studied the selective extraction/adsorption of benzenesulfonate relative to benzoate. At high pH, when both acids are deprotonated, benzenesulfonate was selectively removed from water in this coupled system and a separation factor of 4.8 [+-] 0.5 was measured. This separation factor resulted because the benzenesulfonate ion pair is preferentially partitioned (2.8-fold) and preferentially adsorbed (1.7-fold), compared to the benzoate ion pair. At lower pH's when benzoate, but not benzenesulfonate, is protonated, the separation factor for benzenesulfonate was considerably larger. Thus by exploiting differences in ion pair partitioning and adsorption, and differences in pK[sub a]'s, the acids could be separated using the coupled extraction and adsorption system.

Solid-Phase Extraction of Ascorbic Acid 2-Sulfate from Cysts of the Brine Shrimp Artemia franciscana

Two procedures are described for the solid-phase extraction of ascorbic acid 2-sulfate from cysts of the brine shrimp Artemia, The first one is based on reversed-phase ion pair extraction on an octadecylsilica cartridge using tetrabutylammonium as the counterion, followed by elution with methanol. In the second procedure ascorbic acid 2-sulfate is retained on a DEAE silica cartridge and eluted with 0.1 M sodium salicylate. Both approaches were used as part of a quantitative reversed-phase ion pair liquid chromatographic method with detection at 254 nm. The anion exchange extraction procedure is superior to its ion pair counterpart in terms of recovery (88.7 +/- 3.5% versus 63.0 +/- 12.7%), reproducibility (CVs of 3.6-7.7% versus 6.3-18.7%), and simplicity.

Determination of parts-per-billion concentrations of indium in biological materials by electrothermal atomic absorption spectrometry following ion pair extraction

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of parts-per-billion concentrations of indium in biological materials by electrothermal atomic absorption spectrometry following ion pair extractionWei. Zheng, I. Glenn. Sipes, and Dean E. CarterCite this: Anal. Chem. 1993, 65, 15, 2174–2176Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://doi.org/10.1021/ac00063a044RIGHTS & PERMISSIONSArticle Views70Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (397 KB) Get e-Alerts Get e-Alerts

Extraction of contour lines by identification of neighbor relationships on a voronoi line graph

AbstractThe studies on automatic extraction of contour lines have attracted interest in building a map information system as an automatic composition of input data. However, many attempts reported so far considered only the local connection relationship of contour lines and did not use global information contained in the whole topographic map. Therefore, they could not cope with extraction of contour lines having various cut forms.The method proposed in this paper can deal with the interconnection of contour lines which are disconnected within a region enclosed by a curved contour line and also the interconnection of contour lines disconnected in the same region, which were difficult in the existing methods. This was because its processing is based on global information of contour lines contained in a topographic map.As an example of the global information, the neighbor relationship built by a Voronoi diagram is used. The proposed method is divided into the following five steps: construction of a Voronoi diagram; identification of neighbor relationships of line segments; determination of height relation of line segments; extraction of contour lines; and extraction of pairs of endpoints to be interconnected. Then, while comparing and verifying them with the features of contour lines, disconnected contour lines are identified and extracted. This paper reports the procedures for processing and then considers the effect of the proposed method by experimental results.