TOF mass spectrum

Therefore, the orthogonal TOF mass spectrum is a snapshot of all the ions in the sampled ion beam at any one moment in time. The arrangement has advantages over magnetic sectors alone and TOF instruments alone (see Chapter 20 for further discussion). 

Figure 12.9 MALDI-TOF mass spectrum of chicken egg-white lysozyme. The peak at 14,307.7578 daltons (amu) is due to the monoprotonated protein, M+H+, and that at 28,614.2188 daltons is due to an impurity formed by dimerization of the protein. Other peaks are various protonated species, M+H rH ...

Figure 5.19 MALDI-ToF mass spectrum, providing a molecular-weight profile of the tryptic peptides derived from spot 22 (see Figure 5.18) of the silver-stained two-dimensional gel of the proteins extracted from the yeast S. cerevisiae. From Poutanen, M., Salusjarvi, L., Ruohonen, L., Penttila, M. and KaUddnen, N., Rapid Commun. Mass Spectrom., 15, 1685-1692, copyright 2001. John Wiley Sons Limited. Reproduced with permission.

Figure 5.5 Typical average pyrolysis Ar MAB/Tof mass spectrum from 0.5 pi, about 50,000 cells, of a tdh+ strain of V. parahaemolyticus serotype 04 K12.

Figure 8.3 Positive ion LD TOF mass spectrum of blood from a P. vivax infected human patient (only asexual parasites have been observed by microscopy estimated parasitemia approximately 72 parasites/pl). Protocol C is used for sample preparation estimated number of parasites deposited per well is approximately 90. A commercial TOF system is used laser wavelength 337 nm. All one hundred single laser shot spectra, obtained from hnear scanning of an individual well, are averaged (no data smoothing). The characteristic fingerprint ions of detected heme are denoted.

Figure 6 Partial MALDI-TOF mass spectrum from PMMA generated by ATRP with ethyl-2-bromoisobutyrate as initiator (inset shows theoretical isotope distribution for lithiated 18-mer of structure 3). (Peak labelled 3 arises from post-source decay of 3 [10].)...

Evidence for a competing disproportionation mechanism (see Figure 1) for the termination of chain ends is provided by the combined presence of the peaks from 4 and 5 in the MALDI-TOF mass spectrum of this PMMA polymer (see Figure 6) [10]. Confirmation of the presence of the unsaturated and saturated chain ends, arising from disproportionation, was obtained by means of and 13C NMR spectroscopy, respectively [11]. 

Figure 19 MALDI-TOF mass spectrum from low molecular weight PET sample. Inset shows expansion of MALDI-TOF spectrum from m/z 950-1170, with peaks annotated with numbers corresponding to proposed assignments (see text for assignments).

Figure 25 MALDI-TOF mass spectrum from di-hydroxyl end-capped PPG, indicating the presence of hydroxyl and ally end-capped oligomers (see text for description of peak annotation).

Confirmation of the modification of the hydroxyl end groups from the PPG can be accomplished by analysis using MALDI-TOF MS [59]. An example MALDI-TOF mass spectrum of a prepolymer based on PPG 2000 is shown in Figure 28. End group and average molecular weight data can be gleaned from the spectrum. The dominant distribution of peaks centred at approximately m/z 2,500... 

Figure 28 MALDI-TOF mass spectrum from MDI/PPG polyurethane prepolymer. Peaks from functionalised oligomers are annotated with numbers corresponding to those described in the text.

Figure 31 MALDI-ToF mass spectrum of a SEC fraction (fraction 43, see Figure 30) from a PC sample oxidised at 300°C. Reprinted from Montaudo et al. [84]. Copyright 2002, with permission from Elsevier.

Fig. 10.10. Positive-ion LDI-TOF mass spectrum of 1,2,3,4,5,6-hexahydrophenanthro-[l,10,9,8-cp ra]perylene. The inset shows an expanded view of the molecular ion signal. Adapted from Ref. [117] with permission. Elsevier Science, 2002.

Figure 2 MALDI-TOF mass spectrum of a ST-PHPMA-COOCH3. Peak series a represent polymer chains with initiator (IBN) end groups peak series b represent polymer chains with methyl ester end groups.

Figure 3 The MALDI-TOF mass spectrum of the chymotrypsin conjugate with a ST-PHPMA-NHNH2 fraction = 1,400). The peaks 1, 2, and 3 are the double-charged, single-charged conjugate, and single-charged double conjugate aggregate, respectively.

Scheme 8. MALDI-TOF mass spectrum of 30. The calculated molecular weight of [Ci8i2Hi2io> Ag]+ 30 is 23091 g/mol...

Fig. 9.30 a) Normalized MALDI TOF mass spectrum of all fractions (taken after 2 h to 72 h of polymerization time) of poly(2-phenyl-2-oxazoline) freed by dissolving the gold core with NaCN solution and collection of the polymer. The calculated mass of the monomer unit (147.17) is in good agreement with the spacing of the mass signals (AM = 146.93) of the most prominent peaks. Based on ear-... 

Figure 9.61 ToF mass spectrum of metal-carbon cluster ions (TiC2+ and ZrnCm+ cluster ions) using a titanium-zirconium (50 50) mixed alloy rod produced in a laser vaporization source (Nd YAG, = 532 nmj and ionization by a XeCI excimer laser (308 ). ( . M. Davis, S. J. Peppernick and A. W Castleman, J. Chem. Phys., 124, 164304(2006). Reproduced by permission of American Institute of Physics.)...

Figure 3-11 Matrix-assisted laser desorption / ionization time-of-flight (MALDI-TOF) mass spectrum of bovine erythrocyte Cu-Zn superoxide dismutase averaged over ten shots with background smoothing. One-half pi of solution containing 10 pmol of the enzyme in 5 mM ammonium bicarbonate was mixed with 0.5 pi of 50 mM a-cyanohydroxycinnamic acid dissolved in 30% (v / v) of acetoni-trile-0.1% (v / v) of trifluoroacetic acid. The mixture was dried at 37° C before analysis. The spectrum shows a dimer of molecular mass of 31,388 Da, singly charged and doubly charged molecular ions at 15,716, and 7870 Da, respectively. The unidentified ion at mass 8095.6 may represent an adduct of the matrix with the doubly charged molecular ion. Courtesy of Louisa Tabatabai.

Sodium chloride may be added to the eluting solvent at a concentration of 0.01 M in order to accentuate sodium adduct ions in the MALDI-TOF mass spectrum and suppress the formation of potassium adduct ions. 

Fig. 7.4 a) The MALDI-TOF mass spectrum (matrix 2,5-dihydroxybenzoic acid) gives an impression of incomplete functionalisation of the peripheral primary amino groups of... 

Figure 2. MALDI-TOF mass spectrum (dithranol matrix) of [Os(bipy)2(l)]2+ complex with partial assignment.

Figure 6 MALDI-Tof mass spectrum. A protein spot separated from rat serum by SP chromatography (indicated by arrow in Fig. 5, fraction II) was digested with trypsin as described in Sec. Ill and analyzed by MALDI-Tof mass spectrometry (TofSpec-E, Micromass). Ions generated as a result of autocatalytic cleavage of trypsin and two internal standards, angiotensin I and adrenocorticotrophic hormone, are indicated.

Fig. 1. MALDI-TOF mass spectrum of an antibacterial peptide isolated from dog Canis familiaris using the CHCA matrix. The dominant signals at m/z 4190.38 and 2095.68 correspond to the [M+H]+ and [M+2H]2+ ions of the same peptide. The doubly charged ion, which is usually not obtained for peptides in MALDI-MS, is probably detected due to the high content of basic lysine and arginine residues.

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