Oligomer size, determinant

Oligomer Size as a Plausible Determinant of Single-Channel Conductance... 

After the entire chain was tested for reaction, the size of each oligomer was determined along with the quantities of char and light products such as carbon monoxide, methane and water. The time was then incremented by At and the process was repeated at the new reaction time. When the desired time was reached, one Markov chain had been completed. 

Molecular mass and molecular-mass distribution of piperylene oligomers were determined by gel-chromatography on chromatograph KhZh-1302 with the use of styrogel columns. Chloroform was the eluent. Polyisoprene molecular mass and molecular-mass distribution were determined by gel-chromatography on chromatograph "Waters" with styrogel columns with pores sizes (A) 510 -1,510 . Toluene was the solvent, temperature 303 0,5K, elution rate - 1 cm /min. 

Occasionally there is the need for simultaneous determination of MW, MWD of polymers and identifica-tion/quantilication of additives [38]. This was the case for polymer and additive analysis of SBR/(softeners, flavour agents, stabilisers) (chewing gum) [41]. The many constituents of the SBR portion of the sample were not resolved, since adjacent components were similar in size. It should be stressed, however, that the need for simultaneous determination of the molecular weight of polymers and the identification/quantification of additives is exceptional rather than the rule. The determination of molecular weight distributions by SEC has indicated that oligomer fractions analysed by dissolution and (Soxhlet) extraction methods may differ essentially [42],... 

Advances in size-exclusion chromatography, coupled with refractive index, absorption, viscosity, and lightscattering detectors, and MALDI-ToFMS, have made it possible to accurately determine molecular weight distribution (oligomer profiling), even at the relatively low values of polymeric additives (up to about 5000 Da). Advances in column design, e.g. high-resolution PS/DVB columns (> 105 plates m-1) mean that SEC can provide a valuable alternative to conventional HPLC techniques for the separation of small molecules. 

Size-based analysis of SDS-protein complexes in polyacrylamide gels (SDS-PAGE) is the most common type of slab gel electrophoresis for the characterization of polypeptides, and SDS-PAGE is one of the most commonly used methods for the determination of protein molecular masses.117 The uses for size-based techniques include purity determination, molecular size estimation, and identification of posttranslational modifications.118119 Some native protein studies also benefit from size-based separation, e.g., detection of physically interacting oligomers. 

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