DRIFTS spectrum representation

Fig. 2. Schematic representation of a mobility spectrometer. Ions created in the ion source are separated in the drift region based on their mobility. The ion swarms reach the detector where their drift times are recorded and plotted in the form of a mobility spectrum (Originally published in the article of Buryakov et al. [9]).

While the line-shapes parameters may not be unequivocally associated with a set of deterministic or theoretical parameters for a given system, the measurement model approach has been shown to adequately represent the impedance spectra obtained for a large variety of electrochemical systems. The line-shape models represent the low-frequency stationary components of the impedance spectra (in a Fourier sense). Regardless of their interpretation, the measurement model representation can be used to filter and thus identify the nonstationary (drift) and high-frequency (noise) components contained in the same impedance spectrum. 

Figure 4.5.42. Schematic representation of real time-drift compensation during impedance spectrum measurement.

FTIR data analysis software enables spectral data for the imcoated filler to be subtracted from that of the coated specimen, thus creating a difference spectrum that enhances absorption bands associated only with the surface treatment. It is important to point out that subtraction does not always yield additional information, especially when a small absorption associated with a surface treatment is obscured by a large absorption associated with the filler. Spectral changes relative to the unhound surface treatment/additive provide insight into the natnre of interaction with the surface. Examples of use of DRIFTS are described in Section 3.5.4.4. DRIFTS spectra can be quantified provided sample preparation/presentation and representation of the data is correct. 

FIGURE 9.8 Total solvent-free (TSA) imaging of mouse brain tissue using CHCA as matrix (1 A) drift time (tj) vs. m/z 2D representation of data. (IB) Total mass spectrum of all ions detected. (2) Insets of the 2D data and ion images of miz values of (A) 863.35, (B) 863.63, and (C) 863.7. For additional details, see ref 19. (From Trimpin, S. Herath, T.N. Inutan, E.D. Wager-Miller, J. Kowalski, P. Claude, E., Walker, J.M. Mackie, K. Anal. Chem. 2010, 82. 359-367. With permission.)... 

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