Topographic plots

Figure 12 Topographic plots of a DMS-IMS analyzer response to 2,4-DNT (left frame) and 2,4,6-trinitrotoluene (right frame). Positions ofions in plots are circled the reactant ion peak is seen at compensation voltage of 8V and drift time of 2 ms. Source (C.R. White et al., unpublished data. New Mexico State University, September 2005.)...

A new analyzer based on ion mobihty has been introduced in 2005 and combines DMS and IMS analyzers in tandem, hence ions are first separated in a DMS drift tube and then characterized by twin IMS drift tubes [62]. Because the DMS is comparatively slow (0.1—1 Hz) and the mobihty spectrometer operates at 30 Hz, mobility spectra can be obtained throughout a DMS sweep of compensation voltage, creating a three-dimensional plot as shown in Figure 12 for DNT and TNT (unpublished experimental results provided by C.R. White et al. at New Mexico State University, September 2005). As shown in the topographic plots of Figure 12, a benefit of ion characterization for K and AK is seen in the improved separation of peaks over DMS and IMS alone. The tandem DMS-IMS was described at the 2005 International Symposium on IMS and is under development requiring detailed evaluation as drift tube improvements are made. 

Figure 13 Topographic plot of results from GC-DMS characterization of a mixture of explosives using a 2 m long capillary column with a fast temperature ramp. Source (A. Cagan, H. Schmidt, and G.A. Eiceman, NMSU, August 2005 unpublished results.)...

In terms of selectivity and reduced sensitivity to initial moisture and inoculum, the results indicate that shorter treatment times are preferred, especially if moisture is either not controlled or poorly controlled. The regression models were next used to generate topographic plots of AX, AG, and AX/AG at the various combinations of inoculum and moisture. 

Fig. 7. Predicted topographic plot of xylan conversion (AX, %) with inoculum amount and moisture content. The ranges presented on the plot are ranges of xylan conversion predicted in each region. The diamond marks the conditions chosen for preparation of treated stems for the extrusion tests.

Fig. 16. Gas chromatography-differential mobility spectrometry (GC-(DMS) topographic plot [retention time (v-axis), compensation voltage (y-axis), intensity (z-axis)] of a mixture of seven explosives (lOOng in acetonitrile) hexamethylene triperoxide diamine (HMTD), ethylene glycol dinitrate (EGDN), triacetone triperoxide (TATP), 2-mononitrotoluene (2-MNT), 4-MNT, 2,4-dinitrotoluene (2,4-DNT), and 2,4,6-trinitrotoluene (TNT).

FIG. 2 A topographical plot of the electrostatic potential adjacent to and outside of a layer of charged hemicylindrical micelles adsorbed to a solid interface. The results were obtained using the boundary integral method (or boundary element method, BEM). All values shown are dimensionless. The half-width of a unit cell was taken to be b = 5 k -1, while the maximum extent into the electrolyte calculated was L = 10k-1. The radius of the cylinder s circular cross-section was assumed to be K —1. The potential is given in dimensionless units, y = efhp. 

To verify the characteristic peaks of volatile metaboHtes detected, further measurements will be carried out including a larger number of patients and healthy persons. Data will be processed using statistical methods to clarify the assignment between the diseases and the characteristic pattern of the IMS topographic plots. In the near future, the results should be confirmed by comparative analysis using mass... 

Figure 16.2.2 (a) Topographic plot and (b) gray-scale image of the same 200 nm X 200 nm... 

Figure 16.2.4 STM image of HOPG. Gray-scale image at low resolution (left) and higher resolution topographic plot right). [Reprinted with permission from C.-Y. Liu, H. Chang, and A. J. Bard, Langmuir, 7, 1138 (1991). Copyright 1991, American Chemical Society.]...

FIGURE 18.8 Topographic plots of compensation voltage versus retention time from the Py-GC-DMS characterization of positive ions for E. coli (a). Micrococcus luteus (b), and B. megaterium (c). The intensity scale ranges from 0.9 V (white) to 2.5 V (black) in equal steps of 0.1 V. (From Schmidt et ah, Microfabricated differential mobility spectrometry with pryrolysis gas chromatography for chemical characterization of bacteria, Anal. Chem. 2004, 76, 5208-5217. With permission.)... 

FIGURE 11.1 Ni-MCC-IMS topographic plot of a breath analysis of a patient diseased with angina lateralis before medication (a) drift time spectra of the relevant peak during medication (b) and signal area of the peak during medication (c). (Reprinted from Vautz, W. Baumbach, J. I. Int. J. Ion Mobil. Spec. 2008, 11, 35-41. Copyright 2008, with permission... 

FIGURE 11.3 Discriminant values calculated from peak patterns detected in 2D GC-IMS topographic plots of breath analyses from 36 lung cancer patients and a healthy control group of 54 subjects. (Reprinted from Bader, S. Urfer, W. Baumbach, J. I. J. Chemometrics. 2006, 20, 128-135. Copyright 2006, with permission from Wiley InterScience.)... 

Since there will be a lot of results, topographical plots will be used to display the data in a more concise manner. If the colour of the topographical plot is orange, it indicates 2 standard error differences for that frequency after the experiment as compared to before the experiment. 

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