Sample molecular weight

The sample concentration also should be kept as low as possible, particularly in analyses of polymers on columns packed with small particle size resins. The maximum sample concentration to achieve maximum resolution decreases as the sample molecular weight becomes higher and the resin particle size becomes smaller. It is usually in the range of 0.05-5 mg/ml, depending on the sample molecular weight and resin particle size. 

Peedc-to-peak resolution in SEC can be calculated by the ratio of peak separation at the peak maxiaut to the sum of the baseline peak widths. This general definition of resolution is less useful in SEC, where a measure of the ability of the column to separate solutes of different molecular weight is required. For this purposes, we define a new term, the specific resolution factor, R, which relates peak resolution to sample molecular weight, assuming all measurements are made within the linear region of the molecular weight calibration curve, equation (4.41)... 

It is now well known that this mechanism leads to separation largely according to the chemical composition of sample polymers practically without interference of the molecular weight so that the compositional distribution of copolymers can be determined11 l6 This means, in turn, that the Rf value is almost independent of the sample molecular weight, and its validity condition is that the sample molecular weight exceeds, e.g., 5 x 104. 

Sample Molecular weight Degree of polymerization Method Refer- ences... 

The power of the method is greatly enhanced by using matrix assistance (matrix assisted laser desorption ionization, or MALDI). Two matrix materials, nicotinic acid and sinapinic acid, which have absorption bands coinciding with the laser employed, have found widespread use and sample molecular weights of up to two to three hundred thousand Da have been successfully analyzed. A few picomoles of sample are mixed with the matrix compound fol-... 

An alternative approach to determine polymer MWDs from DLS data is to assume that the molecular weight distribution can be represented by a mathematical function and then regressing Equation 3 to obtain the best fit values for the parameters involved in the chosen model. This assumption becomes limiting if the function chosen cannot fit the sample molecular weight distribution. In general methods using this strategy are called function fit methods. 

Sample Molecular weight X 10 C.L. fi-Amyl-olysis limit, % Iodine complex, absorption spectrum ... 

Figure 2. Stress vs. strain for telechelic polyisobutylene-based metal sulfonate ionomers. Numbers at each curve indicate sample molecular weight and mole % ion content (in parenthesis).

Problem 4.23 A series of narrow distribution polystyrene standards dissolved in chloroform were injected into a GPC column at 35 C yielding a set of chromatograms. The following data of peak elution volumes and corresponding sample molecular weights were reported [21] ... 

Subject Number of samples Molecular-weight groups percentage of total ( S.D.) in 24-hour urine samples ... 

The conventional slab gel technique SDS-PAGE is an important technique for the routine identity and purity analysis of biotechnology products [36]. A typical SDS-PAGE analysis, run under reducing conditions with Coomassie blue staining, is shown in Fig. 3.21 A. The heavy and light chains of the purified antibody samples are clearly seen in all of the loaded samples. Molecular weight (MW) markers that encompass the bands of interest are also loaded onto the gel. No differences have been detected between cultures run in batch, fed-batch or perfusion modes. 

Sample Molecular weight (Mw x 10-4) Degree of polymerization Volume fraction K33/K11 K33/K22 to to... 

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