Molecular weight size exclusion chromatography

A series of polyvinylpyridine standards of different molecular weight were analyzed by size-exclusion chromatography, yielding the following results. 

The molecular weight of SAN can be easily determined by either intrinsic viscosity or size-exclusion chromatography (sec). Relationships for both multipoint and single point viscosity methods are available (18,19). Two intrinsic viscosity and molecular weight relationships for azeotropic copolymers have been given (20,21) ... 

Hydroxyl number and molecular weight are normally determined by end-group analysis, by titration with acetic, phthaUc, or pyromellitic anhydride (264). Eor lower molecular weights (higher hydroxyl numbers), E- and C-nmr methods have been developed (265). Molecular weight deterrninations based on coUigative properties, eg, vapor-phase osmometry, or on molecular size, eg, size exclusion chromatography, are less useful because they do not measure the hydroxyl content. 

Size-exclusion chromatography (sec) easily and rapidly gives the complete molecular weight distribution and any desired average (6). Thus, it has become the technique of choice for determining molecular weights despite its relatively high initial cost. 

Nonionic polysaccharides are one of the most simple substances to analyze by size exclusion chromatography because they seldom exhibit nonsize exclusion effects. Due to their wide molecular weight distribution, TSK-GEL PW columns are recommended for their analysis. 

Showa Denko K.K. started the Shodex HPLC business in 1973 by developing columns to determine the molecular weight distributions of polymers produced at its petrochemical plant. Since then, more than 600 items of columns have been developed to achieve various kinds of analyses. Among them are several series of columns that can be used for size exclusion chromatography. The abundant variety of columns is one of the important characteristics of Shodex. Any kind of analytical requirements can be satisfied by choosing the appropriate column supplied by Showa Denko. 

ASTM D 5296 - 92 (1994). Standard Test Method for Molecular Weight Averages and Moleeular Weight Distribution of Polystyrene by High Performance Size-Exclusion Chromatography. Annual Book of ASTM Standards, Vol.08.03, pp. 419-431. 

The instrumentation of HdC, including a pump, an injector, a column (set), a detector, and a recorder or computer, is very similar to size exclusion chromatography SEC). The essence of this technique is the column. There are two types of HdC columns open microcapillary tubes and a nonporous gel-packed column. This chapter emphasizes column technology and selection and the applications of this technique on the molecular weight analysis of macromolecules. 

The premise of size exclusion chromatography (SEC) is that solute molecules are separated according to their effective molecular size in solution. SEC allows the separation of fractions according to their molecular weight and eliminates the... 

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