Molecular weight standards water soluble

The SEC columns were calibrated using narrow molecular weight distribution water soluble polymer standards sodium polystyrene sulfonate, NaPSS (Pressure Chemical Company, Pittsburgh, PA) and dextrans (Pharmacia Fine Chemicals, Piscataway, NJ). The universal calibration curve proposed by Grubisic et al. (13) was found not to be applicable for these polymer standards. The alternative calibration procedure of Coll and Prusinowski (J ) which incorporates excluded volume effects in the numerical value of the Flory parameter was found to be applicable for this system ( ). The calibration curve for the two-column network system described above is shown in Figure 3. The Kyyy parameter used on the abscissa of Figure 3 is a normalized elution volume parameter defined by Equation 1,... 

Calibration of a packed column also presents difficulties when using SEC to characterize EOR polymers. No large molecular weight, monodispersed water-soluble polymer standards are available to relate elution volume to molecular weight. Consequently, the usual SEC calibration methods are not applicable and special calibration techniques must be applied. 

To study the molecular distribution of water-soluble and MeOH-soluble portions, gel permeation chromatography (GPC) (Shimadzu LC-IOA) which consisted of a high pressure pump (Shimadzu Co, Model LC-IOAT) was performed with a column of KF-803L, operated at 401 with flow rate of 1.0 mL/min of tetrahydrofuran, The molecular weight of the fractions was determined from calibration curve obtained with polystyrene as a standard. 

The molecular weight of many carboxylic acids which arc freely soluble in cold water (i.e., chiefly the aliphatic acids) can readily be obtained by titrating a known weight of the acids in aqueous solution with standard sodium or potassium hydroxide solution, using phenolphthalein as an indicator. To avoid the use of unduly large quantities of the acid, it is advisable to use Mj2 caustic alkali solution, and in order to obtain a sharp end>point, this alkali solution... 

There are many hundreds of raw material amines commercially available, and a wide variety are used for water treatment applications. They typically have low flash points and are therefore normally dissolved in water down to 20 to 40% strength, to minimize fire risks and permit blending. Additionally, each material has its own specific functional profile covering molecular weight, solubility, volatility, DR, basicity, thermal stability, and other parameters. The standard water treatment amines have all been known and used for 30 to 40 years or more. 

In this study the physical parameters involved in interaction of a major class of meat flavorants, methyl pyrazines, with soy proteins were determined at meat roasting temperatures. Beef diffusate, the water soluble, low molecular weight fraction that constitutes about IX of beef, was shown to contain the necessary precursors to obtain a desirable, thermally generated meat aroma (8). Diffusate was heated under controlled conditions and generated volatiles were transferred to a gas chromatograph for separation and quantitation. Methyl pyrazines, either from heated diffusate or from standard solutions, were measured in the presence of purified soy proteins and the thermodynamics of binding were determined. 

Wood Solubility in 1% NaOH. Wood extraction procedures in 1% NaOH (Tappi Standard T 212) extract most extraneous components, some lignin, and low molecular weight hemicelluloses and degraded cellulose. The percent of alkali-soluble material increases as the wood decays (48). The extraction is done in a water bath maintained at 100 °C. 

---