Strong cation exchange

Example Shaking 50 mL of 0.001 Af cesium salt solution with 1.0 g of a strong cation exchanger in the H-form (with a capacity of 3.0 mequiv g ) removes the following amount of cesium. The... 

With strong cation-exchangers (e.g. with SO3H groups), the usual sequence is that polyvalent ions bind more firmly than mono- or di- valent ones, a typical series being as follows ... 

Column. 15.0 cm x 4.6 mm, packed with a 5/on silica SCX (strong cation exchanger) bonded phase. 

In Fig. 11, separations of chymotrypsinogen A, cytochrome c and lysozyme on strong cation exchangers carrying SO3 groups by gradient elution are shown. 

Fig. 11a. Fractionation of (/) chymotrypsinogen A, (2) cytochrome C and (3) lysozyme on strong cation exchangers, a) Support Fractogel TSK 650(s)SP (conventional type) sample, 1 mg each flow rate, 1 ml/min column size, 150 x 10 mm T.D. Solvent A = 0.02 mol/1 phosphate, pH 6.0 solvent B = A + 1 mol/1 NaCl gradient, 0-10 min, 0% B 10-70 min, 0-100% B. b) Support Fractogel EMD 650(s)SO( — (tentacle type) conditions as in (a) [78]...

Also, nylon-6 waste may be hydrolyzed in the presence of an aqueous alkali metal hydroxide or acid5 to produce an alkali metal or acid salt of 6-aminocaproic acid (ACA). The reaction of nylon-6 waste with dilute hydrochloric acid is rapid at 90- 100°C. The reaction mixture is poured into water to form a dilute aqueous solution of the ACA salt. Filtration is used to remove undissolved impurities such as pigments, additives, and fillers followed by treatment of the acid solution with a strong cation exchange resin. A sulfonic acid cationic exchanger absorbs ACA salt and pure ACA is eluted with ammonium hydroxide to form a dilute aqueous solution. Pure ACA is obtained by crystallization of die solution. 

Figure 8.24 Separation of the major deoxyribonucleosides and their 5 - monophosphate deoxynucleotides on a strong cation exchange column (column one) and a reversed-phase column. The unseparated nucleosides. A, on the ion- exchange column were switched to the reversed-ptose column. Pe2dc Identification A = nucleosides, B d-CMP, C d-AMP, D - d-GJIP, E - d-CVD, P d-UKO, G THD, and H = d-AOO. (Reproduced with permission from ref. 298. Copyright Preston Publications, Inc.)...

Strong cationic-exchange extraction and reversed-phase extraction (eliminates ion pairing when used in place of octadecyl silica. 

Figure 5 Separation of pharmaceuticals, including amines, on strong cation exchange. Column 0.46 x 15 cm Merckosorb SI-60-SCX, 5 p. Eluent 50 mM aqueous ammonium formate-10% ethanol, pH 4.8. Flow 1 ml/min. Temperature 50°C. The peaks are (1) aspirin, (2) paracetamol, (3) phenacetin, (4) caffeine, (5) phenylephrine, (6) salbutamol. (Reproduced with permission of Elsevier Science from Cox, G. B., Loscombe, C. R., Slucutt, M. J., Sugden, K., and Upheld, J. A., /. Chromatogr., 117, 269, 1976).

The polyamines putrescine, cadaverine, spermidine, and spermine, which are seen at elevated levels in some victims of cancer, were separated on a Technicon (The Technicon Company Chauncey, NY) TSM Amino Acid Analyzer packed with an 8% divinylbenzene-co-polystyrene sulfonated resin with post-column ninhydrin detection.111 Amines such as ethanolamine, noradrenaline, hexamethylene diamine, methoxytryptamine, spermine, and spermidine were separated from amino acids on a DC-4A cation exchange resin.112 A similar approach, using a Beckman Model 121M amino acid analyzer equipped with an AA-20 column, was also successful.113 A Polyamin-pak strong cation exchange column (JASCO) was eluted with a citrate buffer for the detection of putrescene, spermine, cadaverine, and 1,5-diaminohex-ane from rat thymus.114 A post-column o-phthaldehyde detection system was used. 

Makino, Y., Suzuki, A., Ogawa, T., and Shirota, O., Direct determination of methamphetamine enantiomers in urine by liquid chromatography with a strong cation-exchange precolumn and phenyl-p-cyclodextrin-bonded semimicrocolumn, ]. Chromatogr. B, 729, 97, 1999. 

The application of polymer monoliths in 2D separations, however, is very attractive in that polymer-based packing materials can provide a high performance, chemically stable stationary phase, and better recovery of biological molecules, namely proteins and peptides, even in comparison with C18 phases on silica particles with wide mesopores (Tanaka et al., 1990). Microchip fabrication for 2D HPLC has been disclosed in a recent patent, based on polymer monoliths (Corso et al., 2003). This separation system consists of stacked separation blocks, namely, the first block for ion exchange (strong cation exchange) and the second block for reversed-phase separation. This layered separation chip device also contains an electrospray interface microfabricated on chip (a polymer monolith/... 

Silica-based restricted access materials (RAM) have been developed for cleanup in bioanalysis, first for low molecular weight compounds in biofluids (Rbeida et al., 2005) and subsequently for biopolymers such as peptides (Wagner et al., 2002). A classification of different types of RAM has been given by Boos and Rudolphi (1997). Novel RAMs with strong cation-exchange functionality have been synthesized and implemented in the sample cleanup of biofluids. Racaityte et al. (2000) have shown that this type of RAM is highly suitable for the online extraction and analysis of... 

TABLE 11.1 Examples of Off-line Strong Cation Exchange On-line RP/MS/MS... 

Essader, A.S., Cargile, B.J., Bundy, J.L., Stephenson, J.L., Jr. (2005). A comparison of immobilized pH gradient isoelectric focusing and strong-cation-exchange chromatography as a first dimension in shotgun proteomics. Proteomics 5, 24—34. 

Burke, T.W., Mant, C.T., Black, J.A., Hodges, R.S. (1989). Strong cation-exchange high-performance liquid chromatography of peptides. Effect of non-specific hydrophobic interactions and linearization of peptide retention behaviour. J. Chromatogr. 476, 377-389. 

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