METHOD FOR MODIFYING A POLYMER SUPPORT MATERIAL, POLYMER SUPPORT MATERIAL OBTAINABLE BY SUCH METHOD, CHROMATOGRAPHY COLUMN, METHOD OF CHROMATOGRAPHIC SEPARATION AND USE OF A POLYMER SUPPORT MATERIAL

Abstract

A method for modifying a support material, in particular a polymeric support material, for use as a stationary phase in an analytical or preparative separation process. The method includes the steps of providing a support material, coating the support material with an oligoamine or polyamine and reacting the support material with a compound comprising a first functional group reactive with amines and/or hydroxy group and an ion-exchange group. Additionally a support material, a chromatography column, a method of chromatographic separation of analytes and the use of such support material.

Claims

1-24. (canceled)

25. A method for modifying a support material for use as a stationary phase in an analytical or preparative separation process, comprising the steps: a) providing a support material, b) coating the support material with an oligoamine or polyamine c) reacting the support material with a compound comprising a first functional group reactive with amines and/or hydroxy groups, preferably an epoxy group, and an ion-exchange group, preferably a quaternary organo-element of main group V, preferably a quaternary ammonium group, wherein step b) and c) are performed in sequence or simultaneously.

26. The method according to claim 26, wherein step c) is followed by a crosslinking step, treating the reaction product resulting from step c) with one or more polyfunctional compounds.

27. The method according to claim 26, wherein the one or more polyfunctional compound in step d) has at least a first functional group reactive with amines and/or hydroxy groups, and at least a second functional group reactive with amines and/or hydroxy groups.

28. The method according to claim 23, wherein the first functional group is an epoxy group and wherein the second functional group is an epoxy group.

29. The method according to claim 25, wherein the oligoamine or polyamine in step b) is selected from the group consisting of polyallylamine, linear or branched polyethyleneimine (PEI), poly(2-methylaziridine).

30. The method according to claim 25, wherein the compound used in step c) is of Formula I ##STR00003## with R being a linear or branched alkyl or ether group; with each of R1, R2 or R3 being selected independently from the group consisting of substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloaklyl or five- or six-membered heterocycle formed between R1 and R2 or R2 and R3 or R1 and R3 and with X being the functional group reactive with amines and/or hydroxyl groups.

31. The method according to claim 30, wherein the compound is of formula I and R is selected from the linear or branched alkyl or ether group consisting of (CH.sub.2).sub.n or (CH.sub.2).sub.nO(CH.sub.2).sub.n with n being selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; and wherein R1, R2 and R3 each or independently being an alkyl group selected from the group consisting of CH.sub.3 and (CH.sub.2).sub.nCH.sub.3, with n being selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; or an alkyl alcohol group selected from the group of linear or branched alkyl alcohols, preferably selected from the group consisting of (CH.sub.2).sub.nOH, with n=being selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

32. The method according to claim 30, wherein the compound is of formula II, III or IV ##STR00004## with R being selected from the linear or branched alkyl or ether group consisting of (CH.sub.2).sub.n or (CH.sub.2).sub.nO(CH.sub.2).sub.n with n being selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

33. The method according to claim 30, wherein the compound used in step c) is of Formula (I), selected from the group consisting of glycidyltrimethylammonium chloride; glycidylmethyldiethanolammonium chloride; and glycidyltriethylammonium chloride.

34. The method according to claim 30, wherein the compound used in step c) is a (Halogenoalkyl)trialkylammonium halogenide selected from the group consisting of: (3-Chloro-2-hydroxypropyl)trimethylammonium chloride, (2-Chloroethyl)trimethylammonium chloride, (2-Bromoethyl)trimethylammonium bromide, (3-Bromopropyl)trimethylammonium bromide, (5-Bromopentyl)trimethylammonium bromide.

35. The method according to claim 26, wherein the polyfunctional compound(s) used in step d) is/are selected from epoxides; halogenalkanes; aldehydes.

36. The method according to claim 35, wherein the epoxides are selected from 1,4-butanedioldiglycidyl ether, trim ethylolpropane trig lycidyl ether, poly(ethylene glycol) diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycidol; and wherein the halogenalkanes are selected from epichlorohydrin, epibromohydrin, 1,1-Oxybis[2-(2-chloroethoxy)ethane]; and 1,2-Bis(2-chloroethoxy)ethane, bis(2-chloroethyl) ether, 1-Chloro-3-iodopropane, 1,4-dibromobutane, 1,3-dibromopropane; and wherein the aldehyde is glutaraldehyde.

37. The method according to claim 25 wherein the reaction product resulting from step c) is treated with one or more monofunctional compounds.

38. The method according to claim 37, wherein the monofunctional compound is a compound having a functional group reactive with amines and/or hydroxy groups.

39. The method according to claim 38, wherein the monofunctional compound is selected from the group consisting of substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloaklyl.

40. The method according to claim 38, wherein the monofunctional compound is selected from halogene alkanes or epoxy alkanes.

41. The method according to claim 25, wherein the PEI is covalently attached to the support material.

42. The method according to claim 41, wherein the PEI is attached to the support material by means of a spacer molecule.

43. The method according to claim 42, wherein the spacer is a polyfunctional molecule with a group reactive with alcohols/amines and the other group reactive with polyamine.

44. The method according to claim 43, wherein the support material provided in step a) comprises groups that are reactive with the spacer molecule on the substrate end.

45. The method according to claim 25, wherein the support material provided in step a) comprises groups that are reactive with epoxides.

46. The method according to claim 25, wherein the support material provided in step a) is selected from the group consisting of hydrocarbon-based compounds; PVA; sugar-based compounds; inorganic compounds.

47. The method according to claim 25, comprising the step of generating hydroxy groups on/in the support material, previous to step b), by a process comprising the steps of oxidative treatment of the polymer support substrate; and subsequent reductive or hydrolytic treatment.

48. The method according to claim 25, wherein the support material is partially derived from aromatic hydrocarbon compounds having at least two vinyl or allyl substituents; and partially derived from monomers selected from the group of ethylvinylbenzene, vinyl acetate, styrene and any combination thereof.

49. The method according to claim 48, wherein the relative amount of aromatic hydrocarbon compounds having at least two vinyl or allyl substituents is at least 50% by weight.

50. The method according to claim 25, wherein step c) or d) is followed by a step e) heating the functionalized and crosslinked material in alkaline solution.

51. A support material for use as a stationary phase in an analytical or preparative separation process obtainable by a method according to claim 25.

52. The support material according to claim 51, wherein the support material provided in step a) is microporous or mesoporous.

53. The support material according to claim 51, wherein the material is stable in a pH range from 0 to 14.

54. The support material according to claim 53, wherein the material is stable in a pH range from 0 to 14 such that the retention time of sulfate in a column packed thereof after one-time rinsing with 1M NaOH solution and/or one-time rinsing with 1M HNO.sub.3 solution does not differ by more than 8% from the retention time of sulfate before such rinsing.

55. A chromatography column filled with a support material according to claim 51.

56. A method of chromatographic separation of analytes, wherein a solution containing the analytes is contacted with polymer support material according to claim 51.

Description

[0104] The following figures illustrate:

[0105] FIG. 1 Schematic representation of substrate modification with PEI;

[0106] FIG. 2 Schematic representation of modification with a compound baring an ion-exchange group;

[0107] FIG. 3 Schematic representation of modification with a crosslinking step;

[0108] FIG. 4 Chromatogram obtainable with a polymer support material according to Example 6.2 in isocratic mode;

[0109] FIG. 5 Change in retention factor k depending on the amount of GTMA used in Example 5.1;

[0110] FIG. 6A, 6B Comparative chromatograms of performance of polymer support material according to Example 5.1 and 6.1;

[0111] FIG. 7A, 7B Chromatograms of polymer support material according to comparative Example A in separating certain ions;

[0112] FIG. 8A, 8B Comparative chromatograms obtainable by polymer support material according to Example 6.2 with low and high crosslinking degree of the coating;

[0113] FIG. 9 Chromatogram obtainable by using a polymer support material according to Example 6.2 in gradient mode;

[0114] FIG. 10: Pressure-flow profile measured on a chromatography column filled with a polymer support material of the invention according to step a);

[0115] FIG. 11: Result of the particle size analysis by SEM (number over diameter [m]);

[0116] FIG. 12: Chromatogram of polymer support material according to example 14 in separating the same ions as in FIG. 4.

EXAMPLE 1: PROVIDING A POLYMER SUPPORT SUBSTRATE

[0117] Polystyrene seed particles were prepared by dispersion polymerization of styrene in ethanol, stabilized with polyvinylpyrrolidone and initiated by means of azo-bis-iso-butyro-nitrile. Polystyrene particles having a mean diameter of 1.5 m (Mn=15 kg/mol, Mw=55 kg/mol) were thus obtained. Polymerization was continued in an emulsion of 55 wt % divinylbenzene (DVB), 45% ethylvinylbenzene (EVB), toluene, in water/isoamyl alcohol, stabilized with polyvinylalcohol and initiated by means of azo-bis isobutyro-nitrile. Thus, porous highly crosslinked poly (DVB-EVB) particles having a mean radius of 4.6 m, specific surface area of 540 m.sup.2/g, and a porosity of 1 cm.sub.3/g were obtained.

EXAMPLE 1.1: DETERMINING THE AVERAGE PORE RADIUS AND THE SPECIFIC SURFACE OF THE POLYMER SUPPORT SUBSTRATE

[0118] The average pore radius of the starting polymer support substrate was determined by nitrogen sorption in the BJH (Barret, Joyner, Halenda) model. The specific surface area was determined by nitrogen sorption in the BET model (Brunauer, Emmett, Teller). For both analyses a sample of 0.10945 g PS/DVB polymer support substrate was used. The density of the sample material was 1.105 g/cc. The measurement was performed on an Autosorb iQ S/N:14713051301 instrument in a 9 mm cell. The bath temperature was 77.35 K. The final degassing temperature was 60 C. The evaluation of the measurement was performed on Quantachrome ASiQwin version 3.01. The measurement was performed twice, once with a soaking time of 80 min, once with a soaking time of 40 min. The outgassing rate was 1.0 C./min and 20.0 C./min respectively. The mean pore radius resulting from the BJH method based on the pore volume was 5.1060 nm. The specific surface area according to the Multi-Point BET plot was calculated to be 540.0 m.sup.2/g.

EXAMPLE 1.2: DETERMINING THE PRESSURE STABILITY OF THE POLYMER SUPPORT MATERIAL

[0119] An oxidation with hydrogen peroxide and a reduction with lithium aluminium hydride was carried out on the starting polymer support substrate. The resulting particle was subjected to a pressure test. For the pressure test, a 2504 mm column was packed with the particle and water was passed through the column at an increasing flow rate. FIG. 10 shows a pressure-flow profile measured at room temperature. The y-axis shows the system pressure in bar. The x-axis shows the flow rate in mL/min. 8 intervals of 30 seconds each were measured, increasing the flow rate stepwise from 0.2 ml/min to 1.6 ml/min. As can be seen in the figure, the pressure is linearly dependent from the flow rate, up to pressures of 400 bar or 40 MPa.

EXAMPLE 1.3: DETERMINING THE AVERAGE PARTICLE SIZE

[0120] The circularity and average particle diameter were determined for a sample of the starting polymer support material provided in step a. The sample was applied to a scanning electron microscope carrier in a single particle layer and coated with gold using a sputter-coater of the type LOT AutomaticSputterCoater MSC1 connected to a Vacubrand RZ 6 vacuum pump. A series of 27 images was taken using a scanning electron microscope (Phenom ProX) and individual particles were identified and measured using Olympus Imaging Solutions Scandium. The identified particles were analyzed for spherical diameter and roundness. All images were analyzed in batch processing with the same threshold values and measurement settings. A total of 6039 particles were measured with a circularity of 0.8. The measurement results are shown in FIG. 11. It shows on the y-axis the number of particles and on x-axis the diameter in m. The smallest measured radii were 0.8 m, the largest up to 10 m. The mean diameter (median) was 4.6 m, with a relative standard deviation of 6.2%. The polydispersity index PDI (Mw/Mn) found to be 1.04.

EXAMPLE 2.1: GENERATING HYDROXY GROUPS

[0121] Oxidation with acetic acid: 61.7 g of the product of Example 1 were suspended in 382 mL acetic acid in a 1 L reactor connected to thermostat. Reaction mixture was heated to 80 C. 121 mL hydrogen peroxide (35%) was added slowly. The reaction mixture was stirred for 24 h, then cooled down and filtered off. The filter cake was washed with ultrapure water to neutral pH and flushed with ethanol. The filter cake was dried in a vacuum oven, to yield 66 g of product.

[0122] Reduction with lithium aluminum hydride: 51.7 g of the dried oxidized product were suspended in 196 mL of dry THF in a 1 L reactor and cooled to 5 C. with thermostat. 92 ml of 2.4M lithium aluminum hydride solution in THF were added carefully while stirring. The reaction mixture was heated to 55 C. and stirred for 48 h. The reaction was stopped by cooling down to 0 C. and adding 80 ml water within 60 minutes. After that, the reaction mixture was diluted and 150 ml sulphuric acid was added while stirring. The reaction mixture was heated to 80 C. for 1 h and filtered off afterwards. It was washed with water to neutral pH and flushed with acetone. The filter cake was dried to yield ca.50 g of product. The whole procedure was repeated twice.

EXAMPLE 2.2: GENERATING HYDROXY GROUPS

[0123] Oxidation with acetic acid: 41 g of the product of example 1 was suspended in 300 mL acetic acid in a 1 L reactor with thermostat. Reaction was heated to 80 C. 79 mL of hydrogen peroxide (35%) was slowly added within 2 h. The reaction mixture was stirred for 18 h, then another portion of 79 ml of hydrogen peroxide was added and the mixture was stirred for another 4 h. The reaction mixture was cooled down, filtered off, washed with ultrapure water to neutral pH and flushed with ethanol. The filter cake was dried in a vacuum oven, to yield 45.1 g of oxidized product.

[0124] Reduction with lithium aluminum hydride: 41.3 g of the oxidized dried product was suspended in 434 mL of dry THF in a 1 L reactor and cooled to 0 C. with thermostat. 5.1 g lithium aluminum hydride was added carefully while stirring. The reaction mixture was heated to 55 C. and stirred for 20-24 h. The reaction was stopped by cooling down to 0 C. and adding 300 ml of water within 60 minutes. Then the reaction mixture was filtered off, the residue was re-suspended, and 41.3 ml 32% hydrochloric acid was added while stirring. The reaction mixture was heated to 80 C. overnight, then filtered off, washed with water to neutral pH and flushed with acetone. The filter cake was dried to yield ca. 39.8 g of the product. The whole procedure was repeated twice.

EXAMPLE 3.1: PROVIDING A LINKER WITH TERMINAL EPOXY GROUPS

[0125] 25 g of the reaction product of Example 2.1 was suspended in 93.75 mL dimethyl sulfoxide and 65.5 mL 1,4-butanediol diglycidyl ether. The flask was subjected to three vacuum/argon cycles. Under constant stirring, 37.5 mL NaOH (aq, 0.6M) was added and the reaction mixture was stirred for 26 h at 28 C. The product was filtered off, flushed with water and ethanol.

EXAMPLE 3.2: PROVIDING A LINKER WITH TERMINAL EPOXY GROUPS

[0126] 10 g of the reaction product of Example 2.2 was suspended in 37.5 mL dimethyl sulfoxide and 25 mL 1,4-butanediol diglycidyl ether. The flask was subjected to three vacuum/argon cycles. Under constant stirring, 25 mL NaOH (aq, 0.6M) was added and the reaction mixture was stirred for 22 h at 28 C. The product was filtered off, flushed with water and ethanol.

EXAMPLE 4.1: PROVIDING A PEI LAYER

[0127] The product of Example 3.1 (substrate) was suspended in ethanol and water mixture. Polyethyleneimine PEI (CAS 25987-06-8) was dissolved in water, stirred and subjected to ultrasonication. The suspended particles and the dissolved PEI were combined and stirred for 23.5 h at 60 C. The weight ratio of PEI to substrate used was 0.4 g per 1 g. The product was filtered off and flushed with water. A schematic representation of the synthesis is provided in FIG. 1.

EXAMPLE 4.2: PROVIDING A PEI LAYER

[0128] The procedure was the same as in Example 4.1, but the product of Example 3.2 was used as a substrate. A schematic representation of the synthesis is provided in FIG. 1.

EXAMPLE 5.1: INTRODUCING AN ION EXCHANGE GROUP

[0129] The worked-up product of Example 4.1 was suspended in ethanol/water, stirred and sonicated. Glycidyltrimethylammonium chloride (GTMA, CAS 3033-77-0) was added, and the reaction mixture was stirred at 60 C. for 4 h. The weight ratio of GTMA to substrate used was 3.2 g per 1 g. The product was filtered off and flushed with water. A schematic representation of the synthesis according to Example 5.1 is provided in FIG. 2.

EXAMPLE 5.2: INTRODUCING AN ION EXCHANGE GROUP

[0130] The procedure was the same as in Example 5.1, but the product of Example 4.2 was used as a substrate and amount of GTMA used was 0.8 g per 1 g of substrate. A schematic representation of the synthesis is provided in FIG. 2.

EXAMPLE 6.1: CROSSLINKING

[0131] The worked-up reaction product of Example 5.1 was suspended in water. 1,4-butanediol diglycidyl ether (1,4-BDDGE, CAS 2425-79-8) was added and the mixture was stirred for 2.5 h at 60 C. The weight ratio of 1,4-BDDGE to substrate used was 2 ml per 1 g. The product was filtered off and flushed with water. A schematic representation of the synthesis according to example 6 is provided in FIG. 3.

EXAMPLE 6.2: CROSSLINKING

[0132] The procedure was the same as in Example 6.1, but the product of Example 5.2 was used as a substrate. A schematic representation of the synthesis is provided in FIG. 3.

EXAMPLE 7: ION CHROMATOGRAPHY

[0133] A 2504 mm column was packed with ion exchange material obtained according to Example 6.2 and a solution of fluoride, acetate, formate, chlorite, bromate, chloride, nitrite, dichloroacetate, chlorate, bromide, nitrate was passed through the column at 20 C. using 9 mM KOH as a mobile phase with a flow rate of 0.8 ml/min. FIG. 4 shows a chromatogram obtained using such column. The ions elute separately each giving rise to a distinct and narrow peak.

EXAMPLE 8: CONTROL OF CAPACITY

[0134] Capacity variation for ion-exchange material was provided by using different amounts of GTMA in the procedure according to Example 5.1. The effect of varying the amount of GTMA used (0.4 g, 0.8 g, 1.6 g, and 3.2 g) was established by measuring the retention factor k for all inorganic analytes from Example 7 in dependence thereof. The results are shown in FIG. 5. As can be seen from FIG. 5, retention of single-charged ions depends linearly on the amount of GTMA added, which allows to control the capacity of the column. At the same time, it was noted that selectivities for all prepared ion exchangers toward tested analytes (measured as retention factors of analytes divided by retention factor of chloride) were almost identical (relative standard deviation <5%) independently from capacity, which indicated that capacity has no effect on column selectivity towards inorganic anions.

EXAMPLE 9: EFFECT OF SUBSTRATE AND LINKER ON SELECTIVITY

[0135] Selectivity coefficients for all analytes from Example 7 except for dichloroacetate relatively to chloride were determined using KOH as an eluent and compared for ion-exchange materials prepared according to Example 6.1 and Example 6.2. For preparing materials according to Example 6.2, the substrates obtainable by Example 3.2 when running the reaction for 16 h, 19 h, 22 h, and 23.5 h were used which provided different length and density of linkers for polyamine attachment. Selectivity coefficients for all analytes were almost identical in all cases, with relative standard deviation being less than 5%, which indicated that variations provided on the previous steps or any potential variations in the scaled-up production process in substrate modification degree and linker length and density had no significant effect on selectivity.

EXAMPLE 10: EFFECT OF CROSSLINKING

[0136] The crosslinking step (see Example 6.1) has been described earlier as beneficial to the performance of an ion exchanger based on material according to the invention. A comparative study of a separation column (2504) packed with ion exchanger material obtainable in Example 5.1 and in Example 6.1 respectively was performed. The analytes were fluoride, acetate, formate, chlorite, bromate, chloride, nitrite, dichloroacetate (DCA), chlorate, bromide, nitrate (KOH eluent, 40 mM, 1.0 ml/min). FIG. 6A shows a chromatogram obtainable by using the material according to Example 5.1. FIG. 6B shows a chromatogram obtainable by using the polymeric support material according to Example 6.1. Crosslinking allows for separate and distinct elution of DCA/chlorate and bromide/nitrate pairs.

COMPARATIVE EXAMPLE A

[0137] A polymeric support material was prepared according to the teachings of Example 4 of EP 3 721 998 A1, except having replaced N-Methylpyrrolidine by N-Methylmorpholine in equal amount. FIG. 7A shows a chromatogram obtainable by using the material according to comparative Example A using KOH eluent. FIG. 7B shows a chromatogram obtainable by using the polymeric support material according to comparative Example A in the presence of other functionalities (NMP, MDEA). As can be seen from the figures, there is often co-elution of different ions of interest when using a polymeric support material according to comparative Example A.

EXAMPLE 11: SELECTIVITY CONTROL

[0138] The crosslinking step (see Example 6.2) has been described earlier as beneficial to the performance of an ion exchanger based on material according to the invention. A low degree of crosslinking requires using the polymer support material in gradient elution mode because of the late elution of multiple-charged anions. A high degree of crosslinking allows for using the polymer support material in isocratic elution mode. Therefore, this step is responsible for control of column selectivity. A comparative study of a separator column (2504) packed with ion exchanger material obtainable according to Example 6.2 with a high degree of crosslinking guaranteed by long reaction time (25 h) and with a low degree of crosslinking obtained by short reaction time (2.5 h) was performed. The analytes were fluoride, acetate/glycolate, formate, chlorite, bromate, chloride, nitrite, dichloroacetate, chlorate, bromide, nitrate, sulphate and phosphate, KOH was used as an eluent. FIG. 8A shows a chromatogram obtainable by using a polymer support material with low crosslinking degree of coating while using gradient elution (increasing KOH concentration during analysis). FIG. 8B shows a chromatogram obtainable by using a polymer support material with high crosslinking degree while using isocratic elution. Both chromatograms allow for clear and distinct separation of the analyte ions of interest, but material with high crosslinking degree allows for faster elution of polyvalent anions and does not require the use of gradient.

EXAMPLE 12: EFFECT OF BATCH VARIATION

[0139] Three different batches of polymer support material according to Example 6.1 were synthetized. Three Columns (2504 mm) were packed and mixture of analytes described in Example 7 was separated using KOH as an eluent in suppressed ion chromatography mode. Relative standard deviation (R.S.D) for retention times of all analytes was less than 5%, which indicates excellent batchto-batch reproducibility of material.

EXAMPLE 13: SEPARATION OF INORGANIC STANDARD IONS AND HALOACETIC ACIDS

[0140] A polymer support material according to the present invention can serve as a basis to produce an anion exchanger which allows for the separation of 5 haloacetic acids in addition to the inorganic standard ions and oxohalides, preferably by using gradient elution with KOH. FIG. 9 shows a chromatogram obtainable by using a polymer support material according to Example 6.2. A separation column (2504) packed with such ion exchanger material was prepared and an analyte solution comprising inorganic standard ions (F, Cl, ClO.sub.2, ClO.sub.3, Br, BrO.sub.3, NO.sub.2, NO.sub.3, PO.sub.4, SO.sub.4) as well as acetate, formate, and five haloacetic acids (MCA, MBA, DCA, DBA, and TCA) was passed with KOH as an eluent through the said separation column (suppressed ion chromatography mode) using gradient elution mode. As can be seen from FIG. 9, all analytes elute separately, giving distinct peaks.

EXAMPLE 14: EFFECT OF CHANGED ORDER STEPS D) AND C)

[0141] The worked-up product of Example 4 (PEI attachment) was treated according to example 6 (BDGE) followed by a treatment according to example 5 (GTMA). FIG. 12 shows a chromatogram obtained by using the polymer support material of example 14. As can be seen from the figure, there is co-elution of all ions of interest (same ions as in FIG. 4) when using a polymeric support material according to example 14.