Gel-permeation chromatography GPC separations

Size-exclusion chromatography (SEC), or gel permeation chromatography (GPC), separates species on the basis of molecular size. Molecular interactions between... 

Gel permeation chromatography (GPC)—separation of synthetic (organic-soluble) polymers. GPC is a powerful technique for polymer characterization using primarily organic solvents. 

Meta- or para-phenylene-bridged oligobismuthines are prepared by the reaction of chlorodiphenylbismuthine and the corresponding dicuprobenzene bis(dimethyl sulfide) complexes [98OM4049]. The products can be isolated by gel permeation chromatography (GPC) separation. 

In contrast to HPLC, where polar effects dominate molecule separation, gel permeation chromatography (GPC) separates molecules according to their molecular size. Types of stationary phase and eluents used for GPC are HIBAR columns (Merck) [33] and Microgel (Chrompack) columns [215] of different pore size with tetrahydrofurane as eluent [33,214,215] Sephadex LH 20 gel and a sodium acetate solution [216] orN,N-dimethylformamide [217] as mobile phase Styragel columns and dimethylformamide eluent containing 2% acetic acid [218] and micro-packed, fiised-silica columns with tetiahydrofiirane as eluent [219]. Detection is by ultraviolet absorbance at the same wavelength discussed in HPLC analysis. 

Figure 5.8 shows a series of MALDI mass spectra obtained from the gel permeation chromatography (GPC) separation of a sample of PTMEG1000. Each mass spectrum corresponds to a particular elution time from the GPC column. These GPC fractions were collected continuously. At each position along the transform track, a high quality MALDI mass spectrum can be generated. 

The enantioselective determination of 2,2, 3,3, 4,6 -hexachlorobiphenyl in milk was performed by Glausch et al. (21). These authors used an achiral column for an initial separation, followed by separation of the eluent fraction on a chiral column. Fat was separated from the milk by centrifugation, mixed with sodium sulfate, washed with petroleum ether and filtered. The solvent was evaporated and the sample was purified by gel permeation chromatography (GPC) and silica gel adsorption chromatography. Achiral GC was performed on DB-5 and OV-1701 columns, while the chiral GC was performed on immobilized Chirasil-Dex. 

Nonionic surfactants, including EO-PO block copolymers, may be readily separated from anionic surfactants by a simple batch ion exchange method [21] analytical separation of EO-PO copolymers from other nonionic surfactants is possible by thin-layer chromatography (TLC) [22,23] and paper chromatography [24], and EO-PO copolymers may themselves be separated into narrow molecular weight fractions on a preparative scale by gel permeation chromatography (GPC) [25]. 

A cleanup procedure is usually carried out to remove co-extracted matrix components that may interfere in the chromatographic analysis or be detrimental to the analytical instrument. The cleanup procedure is dependent on the nature of the analyte, the type of sample to be analyzed, and the selectivity and sensitivity of the analytical instrument used in the analysis. Preliminary purification of the sample extracts prior to chromatographic separation involves liquid-liquid partitioning and/or solid-phase extraction (SPE) using charcoal/Celite, Elorisil, carbon black, silica, or aminopropyl-silica based adsorbents or gel permeation chromatography (GPC). 

Exclusion chromatography is a technique for separating molecules based on their effective shape and bulkiness. The method is generally called size-exclusion chromatography (SEC). When the mobile phase is an organic solvent or a mixture of organic solvent, the technique is called gel permeation chromatography (GPC), in the case of aqueous mobile... 

Gel permeation chromatography (GPC) with SX3 Biobeads (200-400 mesh) in a range of column sizes and solvents is used by most workers [ 189,366,400,402, 453,454,487-489]. Separation has been made primarily between lipid material > 500 A which is the first to elute from such columns followed by the smaller molecules which include most of the organic pollutants that accumulate in sample matrices. 

Size exclusion chromatography (SEC), also known as gel permeation chromatography (GPC), was used for the separation and fractionation of macromolecules on an analytical and preparative scale [17]. The separation occurs predominantly by the hydrodynamic volume of the macromolecules in solution, however, in some cases the polarity of the molecules can also influence the retention times. Like HPLC, the SEC technique is generally very reproducible with regard to its elution times (typically < 1 h) and hence can be used for automated synthesis. But because the cost for an automated SEC system is high, it must be considered as a serial separation technique. In addition, larger scale separations > 100 mg, usually require repetitive injection of small aliquots. 

SEC is presently the most important method for separation and molecular characterization of synthetic polymers. The exclusion chromatography of lipophilic macromolecules is called also gel permeation chromatography (GPC) and for hydrophilic species, the term gel filtration chromatography (GFC) is often applied. It seems that the term gel permeation chromatography is returning probably because the abbreviation SEC means also Securities and Exchange Commission. 

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