Chromatograph, gel permeation

Both preparative and analytical GPC were employed to analyze a standard (NBS 706) polystyrene sample. Fractions were collected from the preparative column, the solvent was evaporated away, and the weight of each polymer fraction was obtained. The molecular weights of each fraction were obtained usmg an analytical gel permeation chromatograph calibrated in terms of both and M. The following data were obtained ... 

Molecular weights were measured using a Waters gel permeation chromatograph 200). Complete details of the equipment... 

A high pressure gel permeation chromatograph (GPC) has been used to monitor the performance of the reactor. A novel aspect of the GPC is that, it too, has been put on-line to the process control computer and both data collection and analysis have been made automatic while giving the operator full interactive facilities. 

Gel Permeation Chromatography. The instrument used for GPC analysis was a Waters Associates Model ALC - 201 gel permeation chromatograph equipped with a R401 differential refractometer. For population density determination, polystyrene powder was dissolved in tetrahydrofuran (THF), 75 mg of polystyrene to SO ml THF. Three y -styragel columns of 10, 10, 10 A were used. Effluent flow rate was set at 2.2 ml/min. Total cumulative molar concentration and population density distribution of polymeric species were obtained from the observed chromatogram using the computer program developed by Timm and Rachow (16). 

In practice, therefore, gel permeation chromatographs are usually cahbrated by running monodisperse specimens of known molar mass, and determining their elution volume. From the results, a graph is plotted of log M against... 

In order to do this, experimental determinations of the intrinsic viscosities of both the standards and the fractions from the unknown polymer are required. It is possible to obtain commercial gel permeation chromatographs that will do this routinely, and hence to exploit the concept of universal cali-hration. Care must he taken, though, to ensure that the separation of the polymer molecules occurs purely as a result of size exclusion. If there are any other specific interactions, e.g. hydrogen bonding, between the polymer and the column packing, such as may occur with water-soluhle polymers, Benoit s approach does not work and the universal cafihrafion plot is not valid. 

Reversed-phase high-performance liquid chromatography (HPLC) column 50 mm x 3.2-mm i.d. with Kromasil 5- um Gig packing High-performance liquid chromatograph coupled to a triple-quadrupole mass spectrometer with an atmospheric pressure chemical ionization (APCI) source Gel permeation chromatograph with a 60 mm x 25-mm i.d. column packed with Bio-Beads SX-3 (50-g)... 

Automated gel permeation chromatograph (Cleanup XL, Abimed Gilson) equipped with 5-mL loop and chromatographic tube, 25-mm i.d., 600-mm long, filled with 52-g of Bio-Beads, S-X3, 200 00 mesh, 33-cm gel bed length GC Gas chromatograph equipped with a split/splitless injector, autosampler, DB-1 fused-silica column, 30 mx 0.25-mm i.d., 0.25-p.m film thickness and electron capture detector... 

ABC Laboratories Model SP 1000 gel permeation chromatograph system equipped with a 31.0 X 2.5-cm glass column of Envirobeads SX-3 select 200 00 mesh (ca 60 g) preconditioned with ethyl acetate-cyclohexane (1 1, v/v)... 

Chabrecek, P, Soltes, L., Kallay, Z., and Novak, I., Gel permeation chromatographic characterization of sodium hyaluronate and its fractions prepared by ultrasonic degradation, Chromatographia, 30, 201, 1990. 

Wyatt, P. J., Hicks, D. L., Jackson, C., and Wyatt, G. K., Absolute gel permeation chromatographic determination of molecular weight and sizes. Part 2. Incorporation of gel permeation chromatography-size exclusion chromatographic measurements, Am. Lab., 20, 108, 1988. 

Hamacher, K. and Sahm, H., Characterization of enzymatic degradation products of carboxymethyl cellulose by gel permeation chromatograph, Carb. Polym., 5, 319, 1985. 

Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution of Certain Polymers by Liquid Size-Exclusion Chromatography (Gel Permeation Chromatograph -GPC) Using Universal Calibration" ASTM D 3593 80, Annual Book of ASTM Standards, ASTM, Philadelphia, PA, revised annually. 

Conjugated boron polymers containing platimnn or palladium atom in the main chain were also prepared by hydroboration polymerization between tetrayne/ metal complex monomers and tripylborane (scheme 16).30 From gel permeation chromatographic analysis [THF, polystyrene (PSt) standards], the number-average molecular weights of the polymers obtained were found to be 9000. The polymers were soluble in common organic solvents such as THF, chloroform, and benzene. The absorption peaks due to tt-tt transition were observed around 390 nm in the UV-vis spectra of these polymers. The fluorescence emission spectra exhibited intense peaks at 490 nm in chloroform. 

Figure 9. Gel permeation chromatographs of EPDMs. The effect of ETCA addition on MWD of EPDMs prepared with Vs.s-Et3AliCl3 (3). Key O, ETCA/V = 10 X, ETCA/V = 15 , ETCA/V = 20.

Solubility of polymers in tetramethyl ammonium hydroxide aqueous solution was measured by dipping the wafer on which the polymer solution was spin-coated, for 1 min. at 25°C. The prebake was carried out at 90°C for 5min. Sensitivity of resists was measured after the exposure with CA 800(Cobilt) or KrF excimer laser(0.9mJ/cm2/1 pulse). The polymer structure was determined by iH-NMR, 13C-NMR(FX90Q apparatus,JEOL) and 2 Si-NMR. The molecular weight distribution was determined with a Toyo Soda Model 801 gel permeation chromatograph at 40°C. The four columns were connected in series, each packed with G-2000H8x3 and G-400H8(Toyo Soda polystylene gel), respectively. 

Goodspeed DP, Chestnut LI. 1991. Determining organohalides in animal fats using gel permeation chromatographic cleanup Repeatability study. J Assoc Off Anal Chem 74(2) 388-394. 

Number-average molar masses were determined using a vapor pressure osmometer (VPO) (Hitachi 117 Molecular Weight Apparatus) at 54.8 0.1°C in toluene (Fisher Scientific, certified A.C.S.) which was distilled from freshly crushed CaH2. The VPO apparatus was calibrated with pentaerythritol tetrastearate (Pressure Chemical). Gel permeation chromatographic (GPC) analyses were performed in tetrahydrofuran by HPLC (Perkin-Elmer 601 HPLC) using six y-Styragel columns (106, 105, 10l, 103, 500, and 100 A) after calibration with standard polystyrene samples. 

Gel permeation chromatographic measurements were performed oj a Waters Associates HPLC with i-Styragel columns (10, 10, 10, and 500ANG) in chloroform with a polystyrene calibration. 

Automated Data Analysis System for a Gel Permeation Chromatograph with Multiple Detectors... 

In most cases, calibration curves were determined at ambient or elevated temperatures using the Waters 150C High Temperature Gel Permeation Chromatograph which includes a sensitive refractive index detector. Otherwise, a modular system consisting of a Waters Model M6000A Solvent Delivery System, a Waters Model U6K Injector and a Waters Model 401 Refractometer, were used at ambient temperature. The mobile phase at room temperature was... 

Optimization of Resolution in Gel Permeation Chromatographic Separation of Small Molecules... 

Calibration of Gel Permeation Chromatograph. The chromatographic system was calibrated using ... 

Calibration of Gel Permeation Chromatograph Polystyrene Calibration. A plot of molecular size in (S) versus elution volume for polysty-rene standards in dichloromethane showed deviation from linearity at about 2,200 which may be attributed to Imperfect column resolution, peak broadening, axial dispersion and skewing. The extensive tailing of the chromatograms of high molecular weight polystyrene standards observed in dichloromethane has also been reported in the literature (23-26). 

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