Reconstructed total ion current

These data for successive scans are then stored for subsequent manipulation. The reconstructed total ion current trace, equivalent to that obtained from a flame ionisation detector in gas chromatography, shows the variation of total ion current with time and allows spectra of interest to be identified. A typical example is shown in Fig. 6A. The background may be subtracted to give clean spectra, and their identification may be attempted using libraries of standard spectra. If a composite spectrum is obtained from two unresolved peaks, complex subtraction routines may be used to obtain a pure spectrum of each of the components. These may be separately submitted for library searching. The spectra may then be plotted or obtained as a mass versus intensity listing. 

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

Fig. 9.10. Reconstructed total ion current trace obtained by El LC/MS of ergot extract Column Spherisorb 5W silica gel (250x5 nm ID), mobile phase dichloromethane - methanol -concentrated ammonia (95 5 0.1), flow rate 1 ml/min. Peaks 1, solvent front 2, agroclavine 3, setoclavine 4, festuclavine 5, pal 1iclavine or isomer 6, pal 1iclavine or isomer 7, N-noragroclavine 8, elymoclavine 9, penniclavine 10, isochanoclavine 11, norchanoclavines I and II 12, chanoclavine I 13, chanoclavine II. (reproduced with permission of John Wiley Sons, Ltd.)...

Figure 17.11. HPLC-ES-MS of PYL-1. (a) Reconstructed total ion current (TIC) (b) UV-trace.

Figure 17.19. Reconstructed total ion currents of library ISO-4, (a) Positive scan mode (b) negative scan mode.

Figure 8. Reconstructed total-ion-current chromatogram (top) and selected mass spectra produced during NH3 Cl SFC-MS run of 20 cSt PDMS. (Adapted from Ref. 31. Copyright 1988 ACS.)...

Fig. 16.5 Reconstructed total ion current (RTIC) chromatograms of a test mixture of 10 compounds, each at a concentration of 0.1 g (1 iL injected split 1 40). Conditions (top) El and (bottom) Na" ionization conditions.

Fig. 3 LCMS Analysis of Fusion rCRALBP (A) RP-HPLC ultraviolet profile ( 220nm) froHi analysis of 1.5 (ig fusion human rCRALBP on a 50- X Vydac C18 column (lx 250 mm) at 50 lL/min usmg the indicated gradient. Solvent A was 0 1% trifluoracetic acid (TFA) and solvent B was 84% acetonitrile, containing about 0.07% TFA. (B) Reconstructed total ion current from electrospray-mass spectral analysis of the fusion rCRALBP liquid chromatography shown in A. (C) Electrospray-mass spectrum of fusion human rCRALBP indicating the presence of a protein of = 39,114 4 (calculated = 39,110). The deconvoluted spectrum is shown in the inset.

Fig 4 LCMS Analysis of Non-Fusion rCRALBP (A) RP-HPLC ultraviolet profile, (B) reconstructed total ion current, and (C) electrospray mass spectrum with the deconvoluted spectrum shown m the inset LCMS analysis of nonfusion human rCRALBP (1.5 p,g) was performed as described in the legend to Fig. 3, yielding a measured protein mass of = 36,347 4 (calculated = 36,343). 

Instrumentation response factors of individual molecular species in a polar lipid class are essentially identical within experimental error after de-isotoping if the experiment is performed in a low lipid concentration region, which avoids lipid aggregation. Hence, it is feasible to quantitate individual molecular species of a polar lipid class through direct comparison of ion peak intensities with that of a selected internal standard in the same class or through the peak area measurement from the reconstructed total ion current chromatograph in comparison to a minimal set of external calibration curves. 

Figure 2 Demonstration of high speed spectral generation (40 spectra/sec) enabling the detection and quantification of coeluting compounds by using GC-TOF-MS. The solid line represents the reconstructed total ion current (RTIC). Retention times differ by approximately 0.2 sec. (From Ref. 17.)...

Figure 4.6 LC-APCI-MS trace (reconstructed total-ion current) for some vulcanisation agents and residues (each 200 pm/kg). Reproduced with permission from K.A. Barnes, L. Castle, A.P. Damant, W.A. Read and D.R. Speck, Food Additives and Containments, 2003,20, 2, 196. 2003, Taylor Francis [21]...

Figure 5.41 The total-ion-current (TIC) trace and reconstructed ion chromatograms from the predicted pseudomolecular ions of Indinavir m/z 614) and its mono- (m/z 630) and dihydroxy metabolites (m/z 646), generated from full-scan LC-MS analysis of an incubation of Indinavir with rat liver S9. Reprinted by permission of Elsevier Science from Identification of in vitro metabolites of Indinavir by Intelligent Automated LC-MS/MS (INTAMS) utilizing triple-quadrupole tandem mass spectrometry , by Yu, X., Cui, D. and Davis, M. R., Journal of the American Society for Mass Spectrometry, Vol. 10, pp. 175-183, Copyright 1999 by the American Society for Mass Spectrometry.

Figure 5.49 (a) Total-ion-current trace, and (b) the reconstructed ion chromatogram of mjz 510.2 0.5 (monooxygenated metabolites) from LC-MS analysis of human microsomal incubation of Glyburide. Reprinted with permission from Zhang, H., Henion, J., Yang, Y. and Spooner, N., Anal. Chem., 72, 3342-3348 (2000). Copyright (2000) American Chemical Society. 

A reconstructed ion chromatogram is a plot showing the variation in intensity of an ion of a particular m/z ratio as a function of analysis time, while the total-ion-current trace shows the variation in the intensity of all ions being produced as a function of analysis time. Simplistically, the TIC will show an increase as a compound elutes from an HPLC column and is ionized. If an ion with a particular m/z value is found to be diagnostic of a compound or series of compounds of interest, then an RIC of this m/z will show where its intensity increases and, therefore, where a compound of interest may have eluted. The mass spectrum at this point can then be examined for further confirmation that it is of significance. 

Figure 5.3. GC-MS analysis of organic pollutants in a sample of natural water, (a) Total ion current chromatogram (b) reconstructed ion current chromatogram (c) mass chromatogram based on the ion m/z 149 current.

What is a reconstructed ion chromatogram (RIC) and how does it allow a specific compound to be located in the total-ion current (TIC) trace from an LC-MS analysis ... 

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. 

Presented in Figures la and 2a are reconstructed partial total ion current chromatograms obtained by the CGC/MS/DA run on the May, 1985 samples. Figures lb and 2b show mass spectra taken at a certain specified time and peak number. Figure lb shows the mass spectrum of phthalate plasticizer in the soil... 

Figure 1. a) Reconstructed Part of the Total Ion Current Chromatogram of a No-Tillage Soil Extract (LKB-2091 CGC/MS/DA) Peaks Represent Compounds. Soil Sample May 9,1985... 

Figure 2. a) Reconstructed Part of the Total Ion Current Chromatogram of a... 

Figure 2. Reconstructed capillary GC-total ion current chromatogram of headspace volatiles of canned black truffle (Tuber Melanosporum) juice.

Figure 3. LC ESI mass spectrometric analysis of the PMP labeled 0-linked oligosaccharide (HPLC peak 2) that was chemically released (0-mode). (A) Ion currents of oligosaccharide ions (m/z = 1005.5), (B) total ion current, and (C) reconstructed mass spectrum. Asterisks denote fragments produced by the ESI process.

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