Resolution peak distribution models

The results of Tables I, II and III confirm the general applicability of the peak overlap model, developed from point statistics, to randomly generated chromatograms. Individual exceptions to the model will undoubtedly be found as experimental testing Is conducted, but, overall, we anticipate modestly good predictions of m from high resolution chromatographic separations when the components are distributed randomly-... 

The possibility of better resolution of the model by addition of new peaks to the yield distribution function (multimodal distribution) that, in addition to hydrocracking continuum description, can also give more information on the mechanism of such a process. 

In a further study, Rill et al. [325] developed a model of gel permeation chromatography that included a bimodal pore stracture. The smallest mode in the pore-size distribution represents the basic background polyacrylamide pore structure of about 1-mn mean radius, and the second mode was around 5 nm, i.e., in the range of size of the molecular templates. The introduction of this second pore structure was found to substantially improve the peak resolution for molecules with molecular sizes in the range of the pore size. 

In the elucidation of retention mechanisms, an advantage of using enantiomers as model templates is that non-specific binding, which affects both enantiomers equally, will cancel out. Therefore the separation factor (a) uniquely reflects the contribution to binding from the enantioselectively imprinted sites. As an additional comparison, the retention on the imprinted phase is compared with the retention on a non-imprinted reference phase. The efficiency of the separations is routinely characterised by estimating a number of theoretical plates (A), a resolution factor (Rs) and a peak asymmetry factor (As) [10]. These quantities are affected by the quality of the packing and mass transfer limitations, as well as the amount and distribution of the binding sites. 

The fact that metastatic potential can be transferred with the plasma membrane [52] has been the basis of studies of the role of cell membrane structure in relation to the ability of cells to metastasize [53]. Moimtford and coworkers [54, 55] have shown that the lipids of the plasma membrane of malignant cells contains about 6% of neutral lipids, wi triglycerides as the predominant fraction. Furthermore they concluded from the occiu rence of high-resolution sharp NMR peaks that these neutral lipids are isotropically distributed in membrane-associated domains. These domains were modelled as oil droplets invading the space between the two halves of the bilayer. 

In connection with this distribution we note that some authors have interpreted the unimodal distribution xbe(v) as evidence against the validity of the MM approach. As we have discussed in Sec. 2.3, the MM approach does not rely on evidence from either experiment or theoretical calculations. The fact that the distribution xbe v), or any other distribution, is continuous and unimodal only means that there is no clear-cut resolution into several peaks corresponding to the various species (as we have seen in the 2-D model). The species can be defined for any distribution independently of its form (except in the extreme case of a delta function). 

The ratios of integral peak areas are proportional to concentration ratios. These can be analyzed as a function of preparation and treatment conditions of a given catalyst system (eg, supported metal, oxide, or sulfide catalysts) and compared with model calculations (49,54). Information on the elemental distributions and on dispersions of active components thus becomes available. With the advent of very brilliant light sources in synchrotons, XPS with high lateral resolution (below 0.2 fim) became available and thus distribution and spreading on catalyst surfaces can be investigated in great detail (55). 

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