Cation exchanger carboxylate

Polymethacrylate Weak cation exchanger (carboxylic acid) ProSwift WCX Dionex Corporation 50x4.6mm 50x 1 mm Ion exchange chromatography of proteins... 

Weakly acidic cation exchange Carboxylic polymethacrylate 5-14 Cations, biochemical separations, transition metals, organic bases, antibiotics, amino acids... 

Bond Elut (Agilent) and CBA ISOLUTE (International Sorbent technology) both representing an irregular end-capped mixed-mode phase of a weak cation exchanger (carboxylic acid) and a mid-polarity sorbent. /V-butyl-scopolamine was extracted accordingly from equine urine [78], Elution of analytes was achieved by the use of a methanolic solution acidified either with 1 M HC1 [54] or 1 % formic acid [78] allowing competition between QTA and hydronium ions. Recoveries were between 96 and 103 % [54] (Table 4). 

Weak cation exchange Carboxylic acid (J. T. Baker)... 

Conversion of a sodium salt of a carboxylic acid into the free acid e.g., if R-SO H represents the cation exchange resin ... 

Weakly acidic cation exchangers—gel type—carboxylic acid functionality... 

Weak cation exchanger—macroreticular type—carboxylic acid or phenolic functionality... 

Carboxylate exchangers contain —COOH groups which have weak acidic properties and will only function as cation exchangers when the pH is sufficiently high (pH > 6) to permit complete dissociation of the —COOH site. Outside this range the ion exchanger can be used only at the cost of reduced capacity. 

Weakly acidic cation-exchange resins have carboxylic groups (COOH) as the exchange sites. When operated on the hydrogen cycle, the weakly acidic resins are capable of removing only those cations equivalent to the amount of alkalinity present in the water, and most efficiently the hardness (calcium and magnesium) associated with alkalinity, according to these reactions ... 

Carboxylic A term describing a specific acidic group (COOH) that contrib- utes cation-exchange ability to some resins. 

Ion exchange, in which cation and/or anion resins are used to replace undesirable anionic species in liquid solutions with nonhazardous ions. For example, cation-exchange resins may contain nonhazardous, mobile, positive ions (e g., sodium, hydrogen) which are attached to immobile acid groups (e.g., sulfonic or carboxylic). Similarly, anion-exchange resins may include nonhazardous, mobile, negative ions (e.g., hydroxyl or chloride) attached to immobile basic ions (e.g., amine). These resins can be used to eliminate various species from wastewater, such as dissolved metals, sulfides, cyanides, amines, phenols, and halides. 

Weakly acidic cation exchangers (e.g. polymethylacrylic acid resins). These resins (Zerolit 226, Amberlite 50, etc.) are usually supplied in the hydrogen form. They are readily changed into the sodium form by treatment with 1M sodium hydroxide an increase in volume of 80-100 per cent may be expected. The swelling is reversible and does not appear to cause any damage to the bead structure. Below a pH of about 3.5, the hydrogen form exists almost entirely in the little ionised carboxylic acid form. Exchange with metal ions will occur in solution only when these are associated in solution with anions of weak acids, i.e. pH values above about 4. 

Examples of liquid cation exchangers are alkyl and dialkyl phosphoric acids, alkyl sulphonic acids and carboxylic acids, although only two appear to have been used to any extent, viz. di-(2-ethylhexyl)phosphoric(V) acid and dinonylnaphthalene sulphonic acid. 

The assumption of the association of Hb in the pores of carboxylic cation exchangers has been advanced in Ref. [47] on the basis of electron microscopy at the maximum filling, almost all the pore surface is filled with Hb associates which are ordered star-shaped structures. Interprotein interaction in the adsorption immobilization of enzymes have been reported in Refs. [74, 75]. 

Fig. 28. Effect of degree of swelling on diffusion coefficient of streptomycin in carboxylic cation exchangers /) KB-4, 2) KFA, J) KB-2, 4) KMDM-6...

Shataeva LK, Kuznetsova NN, Elkin GE (1979) Carboxylic Cation-Exchangers in Biology, (in Russian) Nauka... 

Alpert has shown [47] that poly(succinimide)-silica can be further hydrolyzed to poly (aspartic acid)-silica or condensed with [3-alanine in aqueous solution to form a covalently bonded copolymer of 2-carboxyethyl aspartamide and aspartic acid. The content of carboxyl groups generated by this way has not been quantified directly, but the cation-exchange hemoglobin capacity has been measured for a series of the packings. Thus, the optimal concentration of poly(succinimide) used in the synthesis was found to be 2 5%. 

Analyses for the Saxitoxins. Early methods for analysis of the saxitoxins evolved from those used for toxin isolation and purification. The principal landmarks in the development of preparative separation techniques for the saxitoxins were 1) the employment of carboxylate cation exchange resins by Schantz et al. (82) 2) the use of the polyacrylamide gel Bio-Gel P2 by Buckley and by Shimizu (5,78) and 3) the development by Buckley of an effective TLC system, including a new solvent mixture and a new visualization technique (83). The solvent mixture, designated by Buckley as "E", remains the best for general resolution of the saxitoxins. The visualization method, oxidation of the saxitoxins on silica gel TLC plates to fluorescent degradation products with hydrogen peroxide and heat, is an adaptation of the Bates and Rapoport fluorescence assay for saxitoxin in solution. Curiously, while peroxide oxidation in solution provides little or no response for the N-l-hydroxy saxitoxins, peroxide spray on TLC plates is a sensitive test for all saxitoxin derivatives with the C-12 gemdiol intact. 

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