Organic compounds analysis polymer surfaces

The Chemical analysis of polymers is very similar to the Chemical analysis of low Molecular weight organic compounds, if we make suitable modification to ensure solubility or the availability of sites for reaction (e.g., insoluble specimens should be ground to expose a large surface area). The general methods used for functional group and elemental analysis are applicable. Chemical reactions of polymers also provide means of Chemical analysis, as also their reactions of degradation. 

In starting a residue analysis in foods, the choice of proper vials for sample preparation is very important. Available vials are made of either glass or polymeric materials such as polyethylene, polypropylene, or polytetrafluoroethylene. The choice of the proper material depends strongly on the physicochemical properties of the analyte. For a number of compounds that have the tendency to irreversible adsorption onto glass surfaces, the polymer-based vials are obviously the best choice. However, the surface of the polymer-based vials may contain phthalates or plasticizers that can dissolve in certain solvents and may interfere with the identification of analytes. When using dichloromethane, for example, phthalates may be the reason for the appearance of a series of unexpected peaks in the mass spectra of the samples. Plasticizers, on the other hand, fluoresce and may interfere with the detection of fluorescence analytes. Thus, for handling of troublesome analytes, use of vials made of polytetrafluoroethylene is recommended. This material does not contain any plasticizers or organic acids, can withstand temperatures up to 500 K, and lacks active sites that could adsorb polar compounds on its surface. 

Adsorption of polymers, in general, on the electrode surface is the main property of these (most) electroinactive organic compounds that has been used in their polarographic determination. The polarographic adsorption analysis, the state of which was quite recently reviewed embraces two different methods dc polarographic maximum suppression and ac polarography. 

McCrery et al. [204] have first used LD-FTMS to desorb and ionise organic compounds. The most widely used analytical applications of lasers in FTMS have been for desorption and ionisation of thermolabile and involatile substances and the characterisation of bulk and surface properties of (intractable) materials. LD-FTMS works especially well for polar polymers and additives with MW < 10 kDa. Polymer analysis by LD-FTMS may involve direct determination of the MWDs for oligomers (up to 10 kDa). For high-MW surfactants (>2000 Da),... 

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