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Mass spectrum, chemical noise

FIGURE 7.35 (a) Initial mass spectrum obtained from PMMA microchip device. The mass spectrum is characterized by a substantial chemical noise background most likely due to residual developer solution present in the microchannels, (b) Electrospray mass spectrum obtained with 10 pM angiotensin I (in 50 50 MeOH/H20 containing 1% acetic acid) after the PMMA microchip has been washed with 50 50 MeOH/H20. The simple solvent wash completely eliminates the residual chemical contamination arising from the microchip fabrication step [200]. Reprinted with permission from the American Chemical Society. [Pg.231]

Standard baseline subtraction and smoothing methods are applied to each individual MALDI spectrum after measurement or on-the-fly during acquisition in order to reduce the influence of chemical noise (Figure 2D) (35). While this is performed independently on each mass spectrum, other processing steps such as normalization, recalibration, and peak picking have to account for the large number of individual spectra in MSI data. [Pg.170]

The addition of mass information to mobility information opens new horizons for both ion mobility spectrometry (IMS) and mass spectrometry (MS). The combination of mass and mobility within one spectrum provides information on ion structure that is not possible with either method alone. By adding ion mobility information to mass information, the size of an ion as well as its mass may be measured. For example, MS is often blind to low levels of ions in complex mixtures due to chemical noise of the matrix and to isomeric/isobaric components of the mixture. Thus, the addition of size information to mass information expands the parametric space that can be used for ion detection. [Pg.189]

We are sure that the sensitivity, which is at the moment in the fmol range, can be improved by a few orders of magnitude. A great advantage is the very low background level, also called "chemical noise". Finally, we should mention easy sample preparation, MS/MS capability/4/ and fast total mass spectrum recording. [Pg.342]

A major feature of the MS-MS spectra is the lack of chemical noise relative to the primary MS spectrum. The ions at m/z 580, 583, 439 and 442 appeared in clusters of small background peaks in the conventional mass spectrum, but they are well defined with a substantially greater signal-to-noise ratio in the MS—MS spectra. No isotopes are observed in the MS—MS daughter spectra because the monoisotopic parent was chosen for each of the MS—MS experiments. [Pg.282]

FIGURE 6.S (a) A 2-dimensional ion mobility (y-axis) and mass-to-charge (x-axis) spectrum of the ions resulting from the 70 eV electron ionization of acetone, (b) A series of zoomed-in spectra for the ion signals at 27-30 m/z taken at decreasing temperatures from left to right, and (c) the 2D spectrum of acetone at 80 K, showing complete separation of the nominal isomeric ions 28-30 m/z. Some additional ions also appear in the low temperature spectrum due to the suppression of chemical noise. [Pg.349]


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See also in sourсe #XX -- [ Pg.270 ]




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Chemical noise

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