Overlapping signals

Our calculations show that the systematic errors for the evaluation of the triangle height are lower then for the peak height and peak ar ea. It is to be noted that tangent method allows estimating of the latent peak in the overlapped signals when peak area and peak maximum determination is impossible. 

The direct determination of DB for hyperbranched methacrylates obtained by SCVP of 9 and 10 via ATRP was reported to be impossible due to overlapping signals in the NMR spectra [47]. However, DB of some hyperbranched methacry-... 

In the case of strongly overlapped signals, see Fig. 6.16c, multiple Unear calibration cannot be used for the following reasons ... 

Hirota and coworkers41 reported a planar structure of new polyene macrolide antibiotic YS-822A (65), which they isolated. XH and 13C NMR spectra of 65 showed a number of broad and overlapping signals, but the 1H-1H and 13C- H COSY spectra implied the existence of a mycosamine moiety and several other partial structures. The connectivity of these partial structures was established by extensive 2D NMR experiments, including homonuclear Hartmann-Hahn and heteronuclear multiple-bond connectivity measurements, which led to the determination of the gross planar structure of 65. 

Although ID XH and 13C NMR spectra of 65 in DMSO-dg showed a number of broad and overlapping signals, the 13C- H COSY spectrum afforded the assignment... 

However, to obtain absolute concentrations of metabolites, it is necessary to analyse precisely the area under the resonance line of interest which is especially difficult for overlapping signals. In addition, a reliable calibration technique is needed to assess the correlation between the area under a resonance line and the absolute concentration of the metabolite in the tissue. 

EIGURE 24. REDOR transform of the decay of the peak at 119 ppm clearly indicating two overlapping signals of different dipolar couplings. Reprinted in part with permission from Reference. Copyright 1997 American Chemical Society... 

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