Evaluation tools nuclear magnetic resonance

High-resolution nuclear magnetic resonance spectroscopy, especially 13C NMR, is a powerful tool for analysis of copolymer microstructure [Bailey and Henrichs, 1978 Bovey, 1972 Cheng, 1995, 1997a Randall, 1977, 1989 Randall and Ruff, 1988], The predicted sequence length distributions have been verihed in a number of comonomer systems. Copolymer microstructure also gives an alternate method for evaluation of monomer reactivity ratios [Randall, 1977]. The method follows that described in Sec. 8-16 for stereochemical microstructure. For example, for the terminal model, the mathematical equations from Sec. 8-16a-2 apply except that Pmm, Pmr, Pm and Prr are replaced by p, pi2, p2j, and p22. 

The use of the ANN approach was demonstrated for the first time on polaro-graphic data [85,86], It was first applied to the evaluation of equilibria (using ANN and experimental design methods) as a tool in electrochemical data evaluation for fully inert metal complexes [85] and later on for fully dynamic (labile) metal complexes [86], The general application in chemical equilibria, for the evaluation of potentiometric or nuclear magnetic resonance (NMR) data, for example, was shown recently [87], where it was stressed that the method is general and can also be applied in extraction. 

To evaluate the importance of GC, we must distinguish between the two roles the method plays. First, GC is a tool for performing separations. In this role, GC methods are unsurpassed when applied to complex organic, metal-organic, and biochemical systems made up of volatile species or species that can be derivatized to yield volatile substances. The second role that GC plays is in the completion of an analysis. In this role, retention times or volumes are used for qualitative identification, and peak heights or peak areas provide quantitative information. For qualitative purposes, GC is much more limited than most of the spectroscopic methods considered in earlier chapters. Thus, an important trend in the field has been in the direction of combining the remarkable separation capabilities of GC with the superior identification properties of such instruments as mass, IR, and nuclear magnetic resonance spectrometers (see Section 27B-4). 

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