Integrated intensity values

At high temperatures, the Tj values of 13C nuclei of polysaccharides may be sufficiently long to create difficulties in quantitative estimation of integral intensities. Values have been observed, at 25.2 MHz, of 0.27-0.31 s [C-l-C-5 of a-D-(l—>6)-linked D-mannopyranan at 90°], and, for side chains of branched-chain mannans, of 0.22 s [C-l of a-D-mannopyranosyl groups linked (1—>2) to a main chain of (1—>6)-linked-D-mannopyranosyl residues at90°] and of 0.31 s [C-l atoms of2-0-sub-stituted /3-D-mannopyranosyl side-chain units linked (1—>2) to a similar main-chain, at 70°]. Under such conditions, the n.O.e. values are57... 

A somewhat more complicated method is frequently used to obtain "integrated intensity" values. The photograph is placed on a recording photometer, which provides a graphical record of the transmission along the center line of the diffraction maximum (or along a layer line of the diffraction transform). The ordinates of the trace are proportional to the transmission, T, while the abscissas are distances along the film. The transmission values are then converted to x-ray exposures. 

The output is the integrated intensity value for that particular reflection. FHKL - This is the structure factor calculating program. The input is a list of hkl s and intensity values. The output consists of E values and phase angles to be used as input to the electron density program. ELECDEN - Calculates the electron density and contours the E-map on a Tektronix 4662 digital plotter. PATTERSON - Used to calculate three-dimensional Patterson maps. 

The main advantage of this method lies in its independence of the spectral resolution and of the band profile (Dennison, 1928). A comparison of the approximation methods shows that the three methods give integrated intensity values within a 95% agreement. 

Figure 3. Linear range and intensity saturation for each color class. Integrated intensity values described in Figure 2 were plotted versus dilutions.

If the experiment to which the calculation refers were actually attempted, several differences would appear. A lost important, the x-ray power would be expended over a vide spectrum. The intensity in Equation-4-10 would be the integrated intensity from the short-wavelength limit to the critical absorption wavelength. /Also, gmax and wka would need to be replaced by values that reflect the wavelength range of the integrated intensity. The net effect of all these differences would be to reduce /k below the value of Equation 4-16, perhaps by as much as ten-fold. 

In the spectrum of fully reductively [ C] methylated glycophorin A, the resonance at 42.8 p.p.m. must correspond to the N, N -di[ C]methylated, N-terminal amino acid residue. The ratio of the integrated intensities of the N, N -di[ C]methylLeu resonance to the N, N -di[ C]methyllysine resonances is 5 1, as expected. The integration values determined were valid, because the recycle times of spectra in Figs. 3B, 3C, and 3D were twice the spin-lattice relaxation-times (Tj values) of those of the di[ C]methyl carbon atoms, and also because the n.O.e. values of the N, N -di[ C]methyl and N, N -di[ C]methyl carbon atoms were equivalent. ... 

The integration of the various carbon signals now gives intensity values which are sufficiently accurate for most purposes. 

Fields of Application. In SAXS a calibration to absolute intensity is required if extrapolated or integrated numerical values must be compared on an absolute scale. Examples are the determination of density fluctuations or the density difference between matrix and domains as a function of materials composition. 

Little difference was noted when peak heights were used. The error in the T data is less than + 10%. Nuclear Overhauser enhancement factors (q) were obtained by measuring the integrated intensity of peaks in a difference spectrum from one with enhancement minus one with no enhancement and dividing that value by the integral from the one with no enhancement i.e. n ( nOe no nOe / (I nOe" Accuracy should be 10% or better. Linewidtns were measured at half heights, and chemical shifts are relative to TMS. 

The integrated intensities of the fitted component peaks should then be related to the electron population of different valence states, subject to correction factors, according to the same equation used earlier for quantitative analysis of survey XPS spectra (Eq. 3) [10]. Because photoelectron KEs are similar throughout the valence band region, spectrometer-dependent factors and IMFP values can be assumed to be the same for all states, so that the equation simplifies to ... 

The r1L and 7js components of the spectra obtained are shown in Fig. 33. The vij of the T1L component is 114 kHz and is larger by 5 kHz than that of PBLG-fd2 at 19°C. This suggests that the amplitude of the libration in the stacked state is smaller than that in the free state. The Fq value of the 7js component is 109 kHz and is similar to that of PBLG-fd2. This is compatible with the assumption that the 7js component corresponds to the side chains in the free state. The fraction of the 7jL component is estimated to be about 60% from the integrated intensity of the spectrum at 19°C, which is comparable with the value estimated from T. ... 

The integral intensities of signals of polysaccharides, obtained with a modem spectrometer under the usual operating conditions, are proportional or quasi-proportional, to the number of 13C nuclei present. This has been observed, in particular, in the case of linear hexo-pyranan structures containing one type,11,47,51,55,56 58-61 or two equal types, of linkage,62 or branched-chain polymers having two linkage types,53,58 where the resonances are readily resolved. In such cases, the T values would be low, 0.2 s or less, and the n.O.e. values would be approximately equal. However, few actual determinations of these values have been made, and extrapolation of such assumptions to more-complex polysaccharide structures is not recommended, as outlined in Section V,2,... 

The value of the equilibrium constant for reaction 10 can be calculated from k /kr, from the ratio of the integrated intensities of the 0s(CO) 2 and 0s(C0) H peaks, and from spec-trophotometrie (carbonyl region IR) titration of OsCCO) with Et N. Fortunately, all three values agree quite well. The... 

---