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Map of critical resolution

Fig.1. One-dimensional map of critical resolution illustration of critical resolution with respect to the gradient run time. Fig.1. One-dimensional map of critical resolution illustration of critical resolution with respect to the gradient run time.
A statement about the robustness of the HPLC method for the parameter pH value is given by the map of critical resolution in Fig. 9. [Pg.647]

The determination of robustness criteria is facilitated by maps of critical resolution for two simultaneously varied parameters (Figs. 10 and 11). Such resolution maps can be derived from a systematic method development and can be represented without additional experiments using appropriate simulation software packages. [Pg.647]

Figure 11 depicts a two-dimensional resolution map of critical resolution with... [Pg.648]

Different regions of the variable space will often be associated with different critical peak-pairs. The resolution of a multicomponent mixture thus requires an analysis involving all components in the whole variable space. Inspection of the contour maps of global resolution will allow the evaluation of the robustness of the optimum. Figure 8.16 shows the contour maps for the separation of a set of fifteen phenols (the same cited previously in this chapter), with mobile phases of CTAB and 2-propanol, where an efficiency N = 2500 was considered for all solutes. For the positional criterion (separation factor), the optimum was found for a mobile phase of 0.12 M CTAB-10% 2-propanol (Fig. 8.16a, upper comer of the variable space), whereas for the valley-to-peak criterion it was 0.102 M CTAB-10% 2-propanol (Fig. 8.16b), and for the overlapped fi-actions, 0.107 M CTAB-10% 2-propanol (Fig. 8.16c). [Pg.283]

For a statement of robustness it is important to know which changes of the experimental conditions are acceptable. This information can be obtained during a systematic method development, without additional experimental effort, from a map of critical resolutioif, which represents the critical resolution as a function of one or two chromatographic parameters. [Pg.643]

Figure 10-1. DryLab software version 3.0 modeling the separation of a mixture of naphthalenes. Resolution of the critical pair (the two peaks that elute closest together) is denoted as a function of time of gradient. Experimental runs are shown as sohd lines on the resolution map selected prediction is a dashed line. Figure 10-1. DryLab software version 3.0 modeling the separation of a mixture of naphthalenes. Resolution of the critical pair (the two peaks that elute closest together) is denoted as a function of time of gradient. Experimental runs are shown as sohd lines on the resolution map selected prediction is a dashed line.
This three-dimensional electron-density distribution is represented by a series of parallel sections stacked on top of one another. Each section is a transparent plastic sheet or, more recently, a layer in a computer image) on which the electron-density distribution is represented by contour lines (Figure 3.45), like the contour lines used in geological survey maps to depict altitude (Figure 3.46). The next step) is to interpret the electron-density map. A critical factor is the resolution of the x-ray analysis, which is determined by the number of scattered intensitie.s used in the Fourier synthesis. The fidelity of the image... [Pg.96]

The last of the critical eight aromatic rings is phenylalanine-82, totally invariant over all 60 eukaryotic sequences and the two bacterial cytochromes whose three-dimensional structures are known. It is found nested against the heme, closing the upper left of the heme crevice as shown in Fig. 6. Although this residue was formerly believed from the two-derivative, 2.8 A resolution electron density map of horse oxidized cytochrome to be swung out and away from the heme in ferricytochrome (12-1J ), the four-derivative, 2.0 A map of tuna ferricytochrome has revealed this to be incorrect (15). In both oxidation states, phenylalanine-82 appears to lie next to the heme, and the crevice remains "closed in the sense observed in Fig. 7. [Pg.414]

The potential to extend 2-dimensional covariance NMR to higher dimensionality has its foundations in Eq. (5.13). Thus, Snyder et al. [16] laid the basis for the computation of 4D NOESY spectra. In their strategy, the critical entry point consisted of considering a 4D data set an array of 2D data or a plane-of-planes. In order to Ulustrate the calculations, the terms donor and acceptor planes in combination with donor and acceptor pairs were coined. It should be noted that an acceptor plane is associated with each donor pair 01,0)2) at frequencies < i and < 2- Mapping of either the acceptor planes onto the donor planes or vice versa describes the projection of a dimension onto another, which leads to an increase for direct covariance or to a decrease for indirect covariance in dimensionality of resolution. [Pg.280]

The values of the simultaneously varied chromatographic parameters gradient run time and pH are plotted on the respective axes. The color values of the resolution map describe the critical resolution. The best resolution (Rs = 4.1) is obtained with the uneconomical gradient run time of 230 min and at a pH of 3.0. [Pg.648]

One way to try and compensate for the very low excitation intensities currently inherent in the RSNOM technique is to enhance the Raman signal from the sample. A number of reports have been published in which surface-enhanced Raman SNOM measurements have been made [34,42,44]. This is particularly interesting as the surface topography of a substrate for surface-enhanced Raman spectroscopy (SERS) plays a critical role in the SERS enhancement process. RSNOM provides both a Raman map with spatial resolution comparable to the surface roughness and also a simultaneous topographic image of the SERS substrate. [Pg.198]

The data was input to Drylab , and the resolution map has been obtained and is shown in Figure 1.8. In this case the critical resolution in the chromatogram is plotted as a function of gradient time (min) and mobile phase buffer pH. The resolution map... [Pg.14]

Fundamental rmderstanding of friaion on the atomic and nanometer scales is critical for design of micro- and nanoe-lectromechanical systems. There are two powerful instruments in nanotribology the surface force apparatus and the atomic force microscope. AFM experiments allow high-resolution mapping of friction properties between solids on the nanometer scale and usually indude measurements of friction forces by friction force microscopy (FFM) and adhesion by CFM. In FFM, as a sharp tip scans across a surface in the... [Pg.596]


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