Stationary phase for ion chromatography

Weiss, J. and Jensen, D. (2003) Modem Stationary Phases for Ion Chromatography, Analyt. Biooanalyt. Chem. 375, 81-98. 

Usually, the stationary phases for ion chromatography have a low capacity, in order to reduce the background signal in conductivity detection. Selectivity in ion chromatography can be optimized along the same lines as other chromatographic methods [368]. 

Polybetaine-based materials [291] and polybetaines grafted (or adsorbed) onto an inorganic particle surface are applicable as a stationary phase for ion chromatography [292]. The separation capability of poly[3-diethyl(methyl-methacryloylethyl)ammonium propanesulfonate] (polyDMAPS) grafted to silica gel and physically adsorbed onto silica gel was compared with respect... 

Stationary phases for ion chromatography have a lower exchange capacity than the ones used for classical ion-exchange separations as described in Chapter 12. Therefore, the ionic strength of the eluent can be low and 1 mM solutions are not uncommon. Diluted mobile phases have low conductivity which facilitates detection. However, even with mobile phases of low electrolyte concentration, the background conductivity is too high to allow detection without special techniques. Two principles... 

The following general trends in the development of new stationary phases for ion chromatography can be identified new stationary phases matrices and bonding chemistries improvement of column efficiency, trend toward reduction in the diameter of separation column, and new chemistry of the bonded functional groups/ layers.ti i ... 

Weiss, J. Jensen, D. Modern stationary phases for ion chromatography. Anal. Bioanal. Chem. 2003, 375, 81-98. 

Richens, D. A. (2001), Master s Thesis Use of Macrocyclic ligands in Mobile and Stationary Phases for Ion Separation by Ion Chromatography, Brigham Young University. 

Recently, PHEMA microspheres have been more and more extensively used for IMAC. Separon-IDA-Fe(III) or Cu(II) was prepared. It was found that Cu(II) interacted preferentially with histidine and tryptophan residues, while Fe(III) preferred phosphate residues, as demonstrated by the separation of lysozyme, ribonuclease A, myoglobin, and transferrin on the Cu(II) column and ovalbumin on the Ee(III) column, respectively.The PHEMA-Congo Red-Cu(II) and PHEMA-Cibacron Blue E3GA-Zn(II) microspheres were applied for adsorption of BSA. Without incorporating the metal ions, the dyed sorbents were already good stationary phases for affinity chromatography. As shown in Fig. 2, the addi-... 

In Section 30D, we described some of the applications of ion-exchange resins to analytical separations. In addition, these materials are useful as stationary phases for liquid chromatography, where they are used to separate charged species. In most cases, conductivity measurements are used to detect eluents. 

Persson BA and Lagerstrom PO (1990) Packings and stationary phases for ion pair chromatography. In Unger KK (ed.) Packings and Stationary Phases in Chromatographic Techniqties. New York Dekker. 

The stationary phase for ion-exchange chromatography is usually a resin, such as polystyrene, which consists of amorphous (noncrystalline) particles. Polystyrene is made into a cation exchanger when negative sulfonate (—SOJ) or carboxylate (—CO2) groups are attached to the benzene rings (Figure 23-1). Polystyrene is an... 

Depending on the type of solvent, ECTEOLA-, DEAE- and PEI-celluloses can function as stationary phases for partition chromatography or as ion exchangers this is seen from Fig. 225. 

Other important stationary phases for liquid chromatography are ion-exchange resins (ion-ex-change chromatography, which uses anionic or cationic resins) and porous solids that do not adsorb the analytes but instead have pores so small that access to a fraction of the pore volume by some of the analyte molecules is more or less restricted depending on molecular size (size-exclusion chromatography). 

Besides these chemically bonded residues, it is possible to form stationary phases for ion-exchange chromatography based on cellulose by impregnation. Examples of this are the polyethylene inline (PEI) and the polyphosphate (Poly-P) celluloses. The cellulose exchangers discussed here have to be distinguished based on their use for an anion- or cation-exchange mechanism. Suitable for the... 

Adsorption and ion exchange chromatography are well-known methods of LC. In adsorption, one frequently selects either silica or alumina as stationary phase for separation of nonionic, moderately polar substances (e.g. alcohols, aromatic heterocycles, etc.). This mode works best in the fractionation of classes of compounds and the resolution of isomeric substances (J). Ion exchange, on the other hand, is applicable to the separation of ionic substances. As to be discussed later, this mode has been well developed as a tool for analysis of urine constituents (8). 

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