Typical total ion current chromatogram

A typical total ion current chromatogram of the Tenax trapped canned black truffle (Tuber Melanosporum) juice volatiles is shown in Figure 2. The compounds identified by GC-MS are listed in Table I in the order of elution from the GC column with their characteristic mass spectral data. The identification of these compounds was based on comparison of the mass spectra obtained with those stored in the NIH/EPA library and also with those of authentic compounds. Moreover, an additional search of published standard mass spectra to confirm the identity of unknowns was undertaken (16). 

Identification of volatiles compounds A typical total ion current chromatogram of the Tenax trapped Black Truffle (Tuber Melanosporiim) volatiles is shown in Figure 4. 

Fig. 24a, b. Typical total ion current mass chromatograms for LAS, coproducts, and their intermediates in a effluent b influent samples of an activated sludge sewage treatment plant (after [322] with permission)... 

FIGURE 27-15 Typical outputs for a GC/MS system, in (a), the total ion current chromatogram of a five-component mixture is shown. The components were 1, A/-nitrosodimethylamine. 

Fig. 6. Reconstructed total ion current trace (A) and a single ion chromatogram from mjz 91 (B) for a typical GC-MS run.

A typical ES-MS autosampling procedure with five samples is shown in Figure 17.6. The x- and y-axes represent time and total ion intensity respectively. After injection of a sample, the ion current increases above that arising from the solvent alone. Spectra can then be extracted from the ion chromatogram. Sample injection and detection can be performed in 2-minute-intervals or even less, thus allowing about 300 samples to be analyzed in 10 hours. 

The AP/MALDI spectral data must be averaged for a few minutes to obtain an adequate signal-to-noise ratio. In fact, the current ion detected is typically unstable due to both the intrinsic nature of the AP/MALDI process and to the peculiarity of the analyzed sample. Oscillations in the ion current values are represented by the total ion chromatogram (TIC) shown in Figure 38.2. Nevertheless, an acquisition lasting less than 2 min is sufficient to obtain a representative AP/MALDI spectrum (Figure 38.3). 

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