Polyacrylamide , reducing

Determine the level of substitution by running a sample of the pooled RNase-antibody conjugate on an SDS-polyacrylamide reducing gel and comparing the density of the bands of the RNase and the heavy and light chains of the antibody with a standard curve of known concentrations of RNase and antibody. 

Elute the antigen (-f mAb) by heating beads for 5 min at 95 C with an equal volume of SDS sample buffer and run on an SDS-containing 10% polyacrylamide reducing gel. Run pre-stained markers on these gels because they will transfer to blots and assist in determining the size of the proteins. 

Both in situ cross-linking of partially hydroly2ed polyacrylamides (69) and injection of quaternary ammonium salt polymers having long hydrophilic side chains (70) have been used to reduce the permeabiUty of water-producing 2ones adjacent to production wells. This permeabiUty reduction decreases the produced water oil ratio as does injection of polyacrylamide in high hardness brine to reduce permeabiUty (71). 

In addition to the normal problems of completely dissolving particles of water-thickening polymers, xanthan gum contains insoluble residues which decrease polymer injectivity. Various methods of reducing insolubles content and improving xanthan solution injectivity are available (80—87). None appears economically viable. Oxygen scavengers (88) and bactericides (77,89) are commonly used to stabili2e injected polyacrylamide and xanthan gum solutions (90—102). 

Acrylamide graft copolymers such as those with starch (qv)(131), dextran (132), and lignin (qv) (133), have been studied to try to reduce copolymer costs. A general disadvantage of acrylamide copolymers is greater cost compared to partially hydroly2ed polyacrylamides. 

The substantial decrease of polyacrylamide solution viscosity in mildly saline waters can be uti1i2ed to increase injection rates. A quaternary ammonium salt polymer can be added to the polyacrylamide solution to function as a salt and reduce solution viscosity (144). If the cationic charge is in the polymer backbone and substantially shielded from the polyacrylamide by steric hindrance, formation of an insoluble interpolymer complex can be delayed long enough to complete polyacrylamide injection. Upon contacting formation surfaces, the quaternary ammonium salt polymer is adsorbed reducing... 

Surfactants evaluated in surfactant-enhanced alkaline flooding include internal olefin sulfonates (259,261), linear alkyl xylene sulfonates (262), petroleum sulfonates (262), alcohol ethoxysulfates (258,261,263), and alcohol ethoxylates/anionic surfactants (257). Water-thickening polymers, either xanthan or polyacrylamide, can reduce injected fluid mobiHty in alkaline flooding (264) and surfactant-enhanced alkaline flooding (259,263). The combined use of alkah, surfactant, and water-thickening polymer has been termed the alkaH—surfactant—polymer (ASP) process. Cross-linked polymers have been used to increase volumetric sweep efficiency of surfactant—polymer—alkaline agent formulations (265). 

Polyacrylamide gel electrophoresis is one of the most commonly used electrophoretic methods. AnalyMcal uses of this technique center around protein characterization, for example, purity, size, or molecular weight, and composition of a protein. Polyacrylamide gels can be used in both reduced and nonreduced systems as weU as in combination with discontinuous and ief systems (39). 

The larger macromolecules can be separated using larger particle size columns. However, the flow rate should be watched carefully. As the effective hydrodynamic size of the macromolecules may be reduced due to the deformation by shear (23). Figure 22.8 shows that the effective hydrodynamic size of a 12-15 X 10 MW polyacrylamide sample will not reach its maximum, or the size without shear, unless the flow rate is reduced to 0.01 ml/min. A... 

Figure 9.3 Schematic illustration of the electrophoretic transfer of proteins in the chromatophoresis process. After being eluted from the HPLC column, the proteins were reduced with /3-mercaptoethanol in the protein reaction system (PRS), and then deposited onto the polyacrylamide gradient gel. (PRC, protein reaction cocktail). Reprinted from Journal of Chromatography, 443, W. G. Button et al., Separation of proteins by reversed-phase Mgh-performance liquid cliromatography , pp 363-379, copyright 1988, with permission from Elsevier Science.

To maintain a high polymerization rate at high conversions, reduce the residual amount of the monomer, and eliminate the adverse process of polyacrylamide structurization, polymerization is carried out in the adiabatic mode. An increase in temperature in the reaction mixture due to the heat evolved in the process of polymerization is conductive to a reduction of the system viscosity even though the polymer concentration in it rises. In this case, the increase in flexibility and mobility of macromolecules shifts the start of the oncoming gel effect into the range of deep transformation or eliminates it completely. 

Cross-hnked polyacrylamides are a group of hydrophihc solid supports introduced primarily for preparation of biopolymers (Fig. 4). Unhke PS resins, polyacrylamides have excellent swelling capacity in both protic (water, alcohols) and aprotic (dichloromethane, dimethylformamide) solvents [88]. These beads are stable towards bases, acids, and weak reducing and oxidizing agents [89]. Predictably, conditions under which amide bonds are cleaved (i.e., sodium in liquid ammonia) [90] lead to rapid decomposition of the polymer. 

The drag-reducing properties of a polyacrylamide type were tested in two-phase air/water flow, using a horizontal pipe of 31-nun diameter [1545]. The properties of the polymer were tested in single-phase water flow, and the results were found to comply with the reduction in pressure drop found by other workers. Positive effects in two-phase flow were found to depend on the Reynolds... 

Jackson, P., The use of polyacrylamide-gel electrophoresis for the high-reso-lution separation of reducing saccharides labeled with the fluorophore 8-ami-nonaphthalene-l,3,6-trisulfonic acid. Detection of picomolar quantities by an imaging system based on a cooled charge-coupled device, Biochem. ]., 270, 705, 1990. 

Figure 1 compares the conversion predicted for any reduced time I = k t with the use of Keller s theory and the above values of k /k and k2/k with experimental results obtained when polyacrylamide was exposed to 0.2N NaOH at 53 C. It may be seen that the reaction slows down at large x much more than predicted by Keller s model. In fact, this decrease of the reaction rate is even more pronounced than predicted by Keller s equations for the case where a single reacted nearest neighbor completely inhibits amide hydrolysis. We believe that this discrepancy is due to the repulsion of the catalyzing hydroxyl ions from amide residues by non-neighboring carboxylate groups. 

Friction reducers such as partially hydrolyzed polyacrylamide may also be used in drilling fluids (19). They allow fluid to be circulated through the well bore more easily thereby reducing horsepower requirements for the circulating pumps and thus decreasing well treatment costs. 

High fluid injection rates are often required. For this reason, friction reducers are often used in acid fracturing. These include polyacrylamide and acrylamide copolymers, guar gum, hydroxyethyl cellulose, and karaya gum (108)... 

Cationic polyacrylamide may be used in the initial treatment stages to promote rapid polymer adsorption (201). Adjustment of the pH may allow deeper penetration of the fluids in an aluminate crosslinking system prior to gelation (202). A process involving injection of alternate slugs of stoichiometrically equivalent amounts of partially hydrolyzed polyacrylamide and Al O ) has been evaluated in the laboratory permeability of sana packs were reduced by more than 96% (203). Mixtures of Al(IIl) and Zr(IV) have also been evaluated as partially hydrolyzed polyacrylamide crosslinkers (204). 

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