Ion-exchanger strong

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/... 

Propyl sulfonic acid Si-O-Si-C -CH2CH2CH2-SOiNa+ Ion exchange Strong cation exchange substrate for aqueous and biological samples effective for the separation of weaker cations such as pyridinium compounds... 

Propyl, trimethylamino Si-O-Si-C -ch2ch2ch2-n+(ch3)2ci- Ion exchange Strong anion exchange phase for aqueous and biological samples suitable for weaker anions such as carboxylic acids properties may be modified or conditioned by proper formulation of buffer mobile phases (see the appropriate table in the Solution Properties chapter)... 

Type of ion-exchanger Strong cation Strong cation Weak anion Strong anion... 

Separation by ion exchange Strongly basic or weakly basic ion exchange resins are used to separate selectively the uranium from the weakly acidic or alkaline solutions from the leaching step. The uranium is eluted from the ion exchange resins with nitrate or chloride solutions as anionic (carbonato- or sulfato-) complexes. 

Vockenhuher et al. (2007) separated tantalum and hafnium by ion exchange. Strongly basic anion exchange resin Dowex 1X8 (mesh 200-400) was prepared by immersion in a 1 1 mixture of 1 M hydrofluoric and 1 M nitric acid overnight. The same acid mixture was used as eluant and it was possible to eluate out pure Hf fraction free from tantalum. 

Cellulose can be bonded easily and versions of PEI (polyethyleneimine), DEAE (dieth-ylaminoethyl), and AC (acetylated) bonded cellulose standard layers are available. Polyamide 6 (e-aminopolycaprolactam) prepared layers have been used for separations of compounds in which hydrogen bonding aids in the separation. Ion exchange (strong anion and cation) sorbents can be combined with cellulose to make prepared plates. 

Besin Ion Exchangers Strongly acid cation exchangers... 

Ion exchange Strong base Partisll-SAX Porous Amino adds. 

The ion-exchange reaction of a monovalent cation, M+, at a strong acid exchange site is... 

Ohta and Tanaka reported a method for the simultaneous analysis of several inorganic anions and the cations Mg + and Ca + in water by ion-exchange chromatography. The mobile phase includes 1,2,4-benzenetricarboxylate, which absorbs strongly at 270 nm. Indirect detection of the analytes is possible because their presence in the detector leads to a decrease in absorbance. Unfortunately, Ca + and Mg +, which are present at high concentrations in many environmental waters, form stable complexes with 1,2,4-benzenetricarboxylate that interfere with the analysis. 

Unsaturated aldehydes undergo a similar reaction in the presence of strongly acid ion-exchange resins to produce alkenyUdene diacetates. Thus acrolein [107-02-8] or methacrolein [78-85-3] react with equimolar amounts of anhydride at —10°C to give high yields of the -diacetates from acetic anhydride, useful for soap fragrances. 

Ion-exchange resins are categorized by the nature of functional groups attached to a polymeric matrix, by the chemistry of the particular polymer in the matrix, and by the porosity of the polymeric matrix. There are four primary types of functionaHty strong acid, weak acid, strong base, and weak base. Another type consists of less common stmctures in specialty resins such as those which have chelating characteristics. 

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