Gel permeation chromatographic analysis

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. 

Table I. Results of Gel Permeation Chromatographic Analysis of Copolymers of NIPAAM...

The molecular weight distribution of SAN copolymers can be determined by gel permeation chromatography [10]. SAN copolymers are soluble in common solvents such as tetrahydrofuran. The solubility characteristics of SAN copolymers, combined with the commercial availability of columns and data analysis software, make gel permeation chromatographic analysis a rapid and routine procedure. The choice of detectors can allow for the determination of absolute molecular weight [11]. Selection of multiple detectors enables characterization of compositional heterogeneity as a function of molecular weight [12], as illustrated in Figure 13.3. 

Gel permeation chromatographic analysis will serve as a valuable technique for evaluating the newly devel-... 

Radical-catalyzed graft copolymerization is generally accompanied by crosslinking or scission (or both) of the substrate polymer. Gel permeation chromatographic analysis of polymer carboxylated by the in situ copolymerization of styrene and maleic anhydride without a radical catalyst shows that the molecular size distribution of the carboxylated... 

A method for the gel permeation chromatographic analysis of the molecular weight distribution of wood pulp holocellulose as the carbanilate derivative has been applied to red maple Acer rubrum) and loblolly pine Pinus taeda). Either the chlorine-ethanolamine or acid-chlorite method could be used to prepare the holocellulose and the derivative was obtained by heating at 80 with phenylisocyanate in pyridine. Higher temperatures caused depolymerization. 

Poly(dextran-g-acrylamides) from ferrous ion—hydrogen peroxide initiation Graft copolymerization of acrylamide onto dextran with ferrous ion-hydrogen peroxide initiation is being studied in detail. The effect of variation of each reaction parameter on graft copolymerization behavior may be measured by direct gel permeation chromatographic analysis of the final product polymer solution. 

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). 

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

A more sensitive viscometer than the drop-time glass capillary method is also needed in size exclusion chromatography (SEC) such as the gel permeation chromatographic (GPC) analysis of polymer molecular weight distribution (MWD). In an SEC system, a concentration detector is commonly used for providing the weight concentration profile of the polymer elution curve. 

GPC Analysis. Molecular weight characterizations were carried out using a Waters 840 Gel Permeation Chromatograph equipped with both an ultraviolet (UV) (Model 481) and a refractive index (RI) detector (Model 410). Two Ultrastyragel columns, in the running order of 1,000 and 10,OOOA pore... 

Gel Permeation Chromatography. A Water Associates model 200 gel permeation chromatograph fitted with five Styragel columns having nominal porosity designations 107, 107,106, 1.5 X 105, and 1.5 X 104 A was used for the analysis of molecular weight distribution in TFE at a temperature of 50.0 0.5°C and a flow rate of 1.00 =t 0.05 ml/min. Further details concerning instrumental and operational parameters, sample preparation and injection, and data acquisition and reduction have been reported elsewhere (I). 

Biphenyl-phosphole copolymer 65 is isolated as an air-stable and soluble powder exhibiting a rather high molecular weight (Mw = 16 000 Mn = 6200) according to gel permeation chromatographic (GPC) analysis. Although multinuclear magnetic resonance spectroscopy and elemental analysis support the proposed structure, the presence of a small number of diene defects is very likely. Polymer 65... 

Rimmer DA, Johnson PD, Brown RH (1996) Determination of phenoxy add herbicides in vegetation, utilising high-resolution gel permeation chromatographic clean-up and methylation with trimethylsilyldiazomethane prior gas chromatographic analysis with mass-selective detection. J Chromatogr A 755 245-250... 

Gel permeation chromatographic (GPC) analysis was not possible directly on the primary-amine-functionalized oligomers because of their tendency to be adsorbed on the GPC columns rather than to elute. A method has been developed in our laboratories (9, 10) for derivatization of the amine end groups with benzophenone to form an imine functionality. This method allows FPC (fixed-partial-charge) analysis of the oligomers. 

Gel permeation chromatographic (GPC) analysis of the molecular weight distribution of the polymers was performed with a Perkin-Elmer series 10 liquid chromatograph equipped with an LC-25 RI detector (25 °C), a 3600 data station, and a 660 printer. A Perkin-Elmer PL 10- xm particle mixed-pore-size cross-linked polystyrene gel column (32 cm by 7.7 mm) was used for the separation. The eluting solvent was reagent-grade tetrahydrofuran (THF) at a flow rate of 0.7 mL/min. The retention times were calibrated against known monodispersed polystyrene standards with MpS of 194,000, 87,000, or 10,200 and for which the ratio Mw/M is less than 1.09. 

However, fractional separation has been the basis for most asphalt composition analysis (Fig. 15.5). The separation methods that have been used divide asphalt into operationally defined fractions. Three types of asphalt separation procedures are now in use (a) chemical precipitation in which n-pentane separation of asphaltenes is followed by chemical precipitation of other fractions with sulfuric acid of increasing concentration (ASTM D-2006) (b) adsorption chromatography with a clay-gel procedure in which, after removal of the asphaltenes, the remaining constituents are separated by selective adsorption/desorption on an adsorbent (ASTM D-2007 and ASTM D-4124) and (c) size exclusion chromatography in which gel permeation chromatographic (GPC) separation of asphalt constituents occurs based on their associated sizes in dilute solutions (ASTM D-3593). 

On-line determination of molar mass (MM) and molar mass distribution (MMD) has become possible with the introduction of an on-line gel permeation chromatograph. Such an instrument does automatic sampling, dilution, injection, elution, detection and analysis, much like an on-line gas chromatograph. Deconvolution is automatic, as is calibration from a mixture of standards. As with all on-line chromatographic techniques, maintenance and reliability are a problem f - large-scale production use. 

Monrabal B, Sancho-Tello J, Montesinos J, Tarin R, Ortin A, del Hierro P, Bas M (2012) High temperature gel permeation chromatograph (GPC/SEC) with integrated IR5 MCT detector for polyolefin analysis a breakthrough in sensitivity and automation. In The applications book, July 2012. LCGC Europe, Chester... 

---