Molecular chromatographic analysis

In a chromatographic analysis of low-molecular-weight acids, butyric acid elutes with a retention time of 7.63 min. The column s void time is 0.31 min. Calculate the capacity factor for butyric acid. 

In the same chromatographic analysis for low-molecular-weight acids considered in Example 12.2, the retention time for isobutyric acid is 5.98 min. What is the selectivity factor for isobutyric acid and butyric acid ... 

Concretes and absolutes, both obtained by total extraction of the plant material and not subject to any form of distillation other than solvent removal, are complex mixtures containing many chemical types over wide molecular weight ranges. In some cases, gas chromatographic analysis shows httle volatile material. Yet these products have powerful odors and contribute in important ways to the perfumes in which they are used. 

To day peak widths are rarely used in chromatographic analysis except for the purpose of calculating peak areas. Peak widths, however, can provide a means of measuring the diffusivity of a solute which is a function of the molecular weight. Consequently, if a reliable relationship between diffusivity and molecular weight can be identified, then the molecular weight of the solute can be assessed. Peak widths of solutes eluted from an open tube can give very precise values of diffusivity. There are a number of equations that purport to relate diffusivity to... 

Gas chromatographic analysis of the product showed two major peaks (relative intensity, 5 1), and the mass spectrum of each peak revealed a molecular ion at i/e 210. The proton magnetic resonance spectrum of the mixture showed that the two products were geometrically isomeric esters. 

Berngard A, A Colmsjo, B-O Lundmark (1993) Gas chromatographic analysis of high-molecular-mass polycyclic aromatic hydrocarbons II Polycyclic aromatic hydrocarbons with relative molecular masses exceeding 328. J Chromatogr 630 287-295. 

A reliable chromatographic method has been developed for the quantitative aneilysis of hydrophobic impurities in water-soluble polymeric dyes. The method utilizes both the molecular sieve effect of normal gel permeation chromatography and solute-column packing interaction, modified by solvent composition. This method eliminates the need to extract the impurities from the polymeric dye with 100 extraction efficiency, as would be required for an ordinary liquid chromatographic analysis. 

Dallas, G. and Abbott, S. D., New approaches to the analysis of low-molecular-weight polymers, in Liquid Chromatographic Analysis of Food and Beverages, Vol. 2, Charalambous, G., Ed., Academic Press, New York, 1979, 509. 

In polymer/additive analysis, spectroscopic methods are used for studying both molecular and atomic composition, usually as a detector for chromatographic techniques. Application of spectroscopic techniques to molecular additive analysis depends on the nature of the sample and its complexity (Table 10.26). Application of the intrinsically simple monocomponent analyses by means of UV/VIS and FUR is rather exceptional for real-life samples. Most industrial samples are complex. It is in the area of multicomponent analysis that most... 

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. 

The composition of the gas stream before and after contact with the catalyst was monitored by subjecting aliquots to gas chromatographic analysis using a Ohkura Model 701 gas chromatograph and two columns. For N2 and O2, a 1 meter molecular sieve 5A column operating at 65°C was employed for N2O, a 2 meter Porapak Q column operating at 89°C was used. 

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