Ion intensity plot

FIGURE 5.13 (a) Set of ion intensity plots of PPO—PEO copolymers (having constant... 

However, the employment of "maximising ion" criteria (6) resolved this dilemma since summed ion intensity plots separated the 19-nor--pregnanetriol from an endogenous steroid 5-pregnene-33,16a,20a--triol, the source of the m/e 157 and 144 peaks. A selected ion plot of m/e 245 from the maximising ion data showed a similar increase in resolution from selected ion plots from unprocessed data (Fig. 3). Metabolites of Nilevar and Orabolin have not yet... 

Fig. 5.8 Computer-drawn ion intensity plots of ions mh 296, 281, 252,179 and total ion intensity (/) versus scan number. The presence of 4-hydroxyphenylacetic acid is confirmed from the appropriate intensity responses of these ions at the expected retention time (arrow) of the compound.

A plot of ion intensity as a function of the ion s mass-to-charge ratios. 

Figure 1 shows a positive static SIMS spectrum (obtained using a quadrupole) for polyethylene over the mass range 0—200 amu. The data are plotted as secondary ion intensity on a linear y-axis as a function of their chaige-to-mass ratios (amu). This spectrum can be compared to a similar analysis from polystyrene seen in Figure 2. One can note easily the differences in fragmentation patterns between the...

Figure 5 Plot of positive CF3 secondary ion intensity versus ellipsometric thickness from a set of perfluoropolyether standards.

In Figure 4 the logarithm of the observed ion intensities was plotted as a function of the logarithm of the pressure in the collision chamber. As the intensity of a product ion of a certain order increases proportionally to the same power of the pressure, the curves in the diagram corresponding to primary, secondary, and tertiary ions are represented by straight lines of slopes equal to 1, 2, and 3, respectively. Measurements were performed with 11 incident ions with different recombina-... 

The ion intensity is plotted vs. the velocity in units of the velocity V0 of the incident ion. The large peak at V0 is attributed to unreacted primary ions. This band shows a tail towards lower velocities since... 

Normalized ion intensities are plotted as a function of retarding voltage. The unlabeled curve gives the observed kinetic energy distribution for reactant zHe and AHe ions shaded and open squares). 

Typical results for these three collision mechanisms are shown in Figure 3 where the relative intensities of the primary, secondary, and tertiary ions are plotted against N, the concentration of molecules in the source. In deriving these curves, the parameters used were kp = 2.0 X 10 9 cc./molecule-sec. k8 = 1.0 X 10 9 cc./molecule-sec. tp = 8.5 X 10 7 sec., (the residence time of the ion (jn/e — 33) in a field of strength 9.1 volts/cm. in the Leeds mass spectrometer). In applying this analysis to a system in which the tertiary ion reacts to form quaternary and higher order ions, ITtotal represents the sum of tertiaries, quaternaries, etc. 

Figure 6. Dependence of intensities of ions BH+(H20)n on drift potential in reaction chamber. The ion intensities decrease as drift potential decreases, however ion ratio shown in upper plot remains constant. B = n-octylamine. From Klassen, J. S. Blades, A. T. Kebarle, P. J. Phys. Chem. 1995, 99,1509, with permission.

The total ion current (TIC) can either be measured by a hardware TIC monitor before mass analysis, or it can be reconstructed by the data system from the spectra after mass analysis. [27] Thus, the TIC represents a measure of the overall intensity of ion production or of mass spectral output as a function of time, respectively. The TIC obtained by means of data reduction, [28] i.e., by mathematical construction from the mass spectra as successively acquired while the sample evaporates, is also termed total ion chromatogram (TIC). For this purpose, the sum of all ion intensities belonging to each of the spectra is plotted as a function of time or scan number, respectively. 

As a calibration procedure in ICP-MS via calibration curves, external calibration is usually applied whereby the blank solution is measured followed by a set of standard solutions with different analyte concentrations (at least three, and it is better to analyze more standard solutions in the same concentration range compared to the sample). After the mass spectrometric measurements of standard solutions, the calibration curve is created as a plot of ion intensities of analyte measured as a function of its concentration, and the linear regression line and the regression coefficient are calculated. As an example of an external calibration, the calibration curve of 239 Pu+ measured by ICP-SFMS with a shielded torch in the pgC1 range is illustrated in Figure 6.15. A regression... 

Another calibration technique - standard addition - minimizes matrix effects because analytes with well defined increasing concentrations are added to a set of sample solutions to be analyzed. The measured calibration curve in the standard addition mode plots the measured ion intensities of analytes versus the concentration added to the sample solution. The concentration of analytes in the undoped sample is then determined by extrapolation of the calibration curve with the x-axis. Matrix matching is subsequently performed and the matrix effects (signal depression or interference problems) are considered. An example of the standard addition technique is described in Section 6.2.6 using solution based calibration in LA-ICP-MS. 

Figure 5. Comparison of SiOf ion intensities for (a) Cr + O 3-APTHS (b) Cr + O 3-APTHS (c) Si + " O 3-APTHS and (d) Si + "O 3-APTHS. Peaks at m z=60,62 and 64 correspond to SiO," ions containing 0, I and 2 O atoms, respectively. The spectra were acquired at room temperature. Curves (a) and (c) are plotted on the same relative intensity scale. Curves (b) and (d) are plotted on the same relative intensity scale. The absolute intensity scale for the figures is arbitrary. Similar results were obtained at 100 C and are summarized in Table S.

Figure. 1. Energy Distributions, a) Experimental Ag+, CfcH5+ and C2H2+ ion intensities from one monolayer of benzene adsorbed on Ag(lll) plotted versus the voltage on the sample.

Empirical Methods. The empirical methods use calibration standards to derive sensitivity factors that can be used to determine the unknown concentration of given elements in similar matrices [3. The sensitivity factors are derived from calibration curves that plot measured secondary ion intensities versus the known concentration of standards. Three types of sensitivity factors have been used the absolute sensitivity factor, the relative sensitivity factor, and the indexed relative elemental sensitivity factor. 

In Figure 2 the positive ion intensities are plotted as a function of time for several major elements in the glass. These depth-composition profiles are compared for unleached and 30 minute aqueous leaching conditions. For each case, the results of profiles on two separate samples have been shown (solid and dashed lines), so that the reproducibility of the method can be judged. 

In Figure 4, the changes in ion intensity for two different reaction times are plotted for 0°C aqueous leaching. The ion... 

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