Polystyrene Ultrastyragel columns

Gel permeation chromatography was performed in tetrahydrofuran using a Waters pump system and a Model 410 differential refractive index detector for the eluant. Five Ultrastyragel columns with nominal porosities ranging from 500 to 105 angstroms were used for all the samples and the polystyrene standards. 

NMP solvent, 1000 A ultrastyragel column, polystyrene standards, phased on FT-NMR of weak vinylic-proton signal in DMSO-d. intrinsic viscosity, dL/g in NMP at 30 C. 

Molecular weights were determined by gel permeation chromatography (GPC) using a Waters HPLC system equipped with noodel 510 pump. Waters model 717 autosampler, model 410 refractive index detector, and model T-50/T-60 detector from Viscotek Corporation with 500, 10, 10 and 10 A ultrastyragel columns in series. Trisec GPC software version 3 was used for calculations. Chloroform was used as the eluent at a flow rate of 1.0 mL per minute. Sanq>le concentrations of 0.2 % wt/vol and injection volumes of 100 )XL were used. Molecular weights were determined based on a conventional calibration curve generate by narrow molecular weight polystyrene standards obtained from Aldrich chemical conq>any. 

Figure 2. Ultrastyragel GPC column specifications based on polystyrene standards, toluene as mobile phase (iml/min).

In the first example, a broad distribution sample of polystyrene was analyzed on a set of high efficiency Ultrastyragel GPC columns (lO. lO jlO A) with which It was determined that Mw = 214,000 and Mn = 87,000. In the Ideal case, a similar set of three (10, 10, lO A) preparative Styragel columns (each 57 mm I.D. X 4 ft) could have been used to fractionate the polystyrene sample. However, we Initially chose to demonstrate the extent of fractionation possible with only one preparative column and selected the lO A column packing material so as not to exclude any of the higher molecular weight fractions. 

A Waters GPC 150 CV, equipped with the DRI prototype 4 and a single capillary viscometer, was used for this study. A low-angle laser lightscattering (LALLS) detector (Chromatix CMX 100) was inserted between the column set and the GPC 150 CV detectors. Tetrahydrofuran (THF) was used at 40 °C and at a flow rate of 1 mL/mn. THF was filtered on a Millipore membrane-type FH and stabilized by lonol at a concentration of 0.04%. The columns used were a set of Waters Ultrastyragel (103—106 A). The narrow standards used for calibration were a set of polystyrene standards... 

In order to standardize the GPC column set (ULTRASTYRAGEL), polystyrene standards and five selected polysilane samples were available. As the latter were not true monodisperse standards, calibration procedures were based on the molecular weights corresponding to the tops of he GPC peaks (Mp). 

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