Spectra secondary ion mass

Thermodynamics of complex formation of silver with several ligands such amines,368 hindered pyridine bases,369 nitrogen donor solvents,370 and azoles371 have been carried out. Other studies include the secondary-ion mass spectra of nonvolatile silver complexes,372 the relationship between Lewis acid-base behavior in the gas phase and the aqueous solution,373 or the rates of hydride abstraction from amines via reactions with ground-state Ag+.374... 

Secondary ion mass spectra were measured using a Perkin-Elmer+PHI 3500 instrument. Experiments were carried out with 4 kV Ar ions at beam currents of 3 and 300 nanoamps. Spectra were measured to at least 500 daltons (d). Samples were prepared in the manner used for the XPS studies. For measurements on the pure complexes, sample charging occurred, as evidenced by the inability to record secondary ion mass spectra. To reduce charging, a low energy electron beam (50-400 eV) was rastered across the sample during SIMS analysis. Positive and negative ion SIMS spectra were recorded however, only positive ion spectra are of interest for this discussion. In the spectra only unipositive ions were detected, so that the mass numbers detected correspond to combinations of the various isotopes of the elements in the ion. Thus an ion at m/z 17 d is assigned to... 

Barber, M. Vickerman, J.C. Wolsten-holme, J. Secondary Ion Mass Spectra of Some Simple Organic Molecules. J. Chem. Soc., Faraday Trans. 1 1980, 76, 549-559. 

Figure 4. Positive and negative secondary ion mass spectra (SIMS) of tantalum...

Figure 7 Secondary ion mass spectra of type 304 before (a) and after (b) exposure to Hs discharge cleaning. (Reproduced, with permission from Ref. 44. Copyright 1980, NHPC.)...

Figures 1-2. Liquid secondary-ion mass spectra. (1) Neurotensin (100 pmol) Mr=1672.9. (2) a) Glucagon (100 pmol) Mr=3482.8 b)...

Figures 3-5. Liquid secondary-ion mass spectra. (3) Bovine insulin (100 pmol) Mr=5733.5. (4) Bovine (Mr=5733.5) and porcine...

A PDP11 based computer system was used for the acquisition, manipulation and storage of secondary ion mass spectra. With the combined setting up and spectral acquisition time of 600 seconds typically, the total dose for both, positive and negative ions per sample was of the order of 2 x 10 atoms per sample. This atom influence falls within established limits for static SIMS spectr of undamaged polymer surfaces (11). 

Figure 7.43. SIMS analysis of lignin, the second most abundant biopolymer in nature, following cellulose. Shown is the phenylpropane subunits and a structural model of softwood Ugnin (top). The secondary-ion mass spectra of pine (softwood) and beech (hardwood) milled wood Ugnin (MWL, a solvent-extracted form of Ugnin from beech wood) are also shown (bottom). Reproduced with permission from Saito, K. Kato, T. Tsuji, Y. Fukushima, TL. Biomacromolecules 2005, 6,678. Copyright 2005 American Chemical Society.

Instrumentation. HPLC isolations were performed on a Beckman 421A system using a Vydac column (C-18, 4.6 x 250 mm). Liquid secondary ion mass spectra (LSIMS) were recorded in the positive ion mode on a Kratos (Manchester, UK) MS-50S mass spectrometer equipped with a 23 kG magnet and post-acceleration detector. The LSIMS ion source has been described elsewhere (28). A Cs+ ion beam of energy 10 keV was used as the primary beam (21). Spectra were recorded (300 sec per decade) with a Gould ES-1000 electrostatic recorder. Tandem MS experiments were performed on a Kratos Concept IIHH (Manchester, UK) four sector instrument of EBEB... 

Fig. 4. Liquid secondary ion mass spectra for the C-terminal peptides (a) Tyr-Arg, a(140-141) and (b) Tyr-His, 0(145-146) as the hexyl ester derivatives.

Fig. 7. Liquid secondary ion mass spectra for peptide a(41-56) containing two hydroxyphenylethyl modifications after (a) C-18 reversed phase HPLC and (b) C-18 followed by phenyl reversed phase HPLC.

Figure 75. Secondary ion mass spectra (SIMS) showing the extent of the solid state reactions between alumina and ceria in a three-way catalyst washcoat (a) as a function of the type of precious metal and (b) as a function of the total precious metal loading (model catalyst on monoliths with 62 cells cm Pt, Pd or Rh loading 1.76 g 1 various total loadings at fixed Pt Rh ratio of 5 1 g/g model washcoat with 70 wt % alumina and 30 wt % ceria, after aging under air at 973 K).

The photoelectron spectroscopic techniques can be supplemented by the more surface and molecular-specific techniques, such as the secondary ion mass spectroscopy (SIMS). In this technique, the polymer surface is sputtered by a noble gas ion beam, such as Ar+ or Xe of <4 KeVand 1 nA/cm" [358], Small percentages of the positively and negatively charged fragments arc extracted into a mass spectrometer (typically of the quadruple type) and provide, in sequential experiments, the positive and negative secondary ion mass spectra, respectively. The time-of-flight SIMS (ToF-SlMS) technique, on the other hand,... 

According to earlier reports, difficulties in isolating the quaternary salts in a pure state and hence in detecting the diastereomers were surmounted by chromatographic separation of their nor-bases derived by pyrolysis 21) of the muscarine chlorides under reduced pressure at 200-240°C. In this way all muscarine diastereomers were found in A. muscaria, Inocybe patouillardi, and I. rimosa (14). Later, owing to impressive developments in instrumental analytical methods, detection and identification of the alkaloids as intact cations by recording secondary-ion mass spectra (SIMS), either of intact mushroom tissue or of ethanol extracts of defatted mushroom tissue, appeared to be possible (22). 

A small CD-ROM based library of around 300 secondary ion mass spectra known as the Wiley-SIMS was created by Henderson and co-workers in Manchester UK. (see http //www.surfacespectra.com). 

The secondary ion mass spectra of most substances contain very many molecular ions which can extend the mass range up to tens of thousands [1A,15]. The molecular ion will contain only neighboring sample atoms if it is formed by direct emission from the surface. Smaller ions can be... 

Hittle, L. R., Altland, D. E., Proctor, A., and Hercules, D. M. Investigation of molecular weight and terminal group effects on the time-of-flight secondary ion mass spectra of polyglycols. Anal. Chem., 66, 2302, 1994. 

Doherty, S. J. and Busch, K. L., "Secondary-Ion Mass Spectra and Fast-Afom-Bombardment Mass Sp>ectra of Liquid Rolymers Alkoxylated Ryrazoles and Hydrazines," Anal Chim. Acta, 187, 117-127,1986. 

FEEM Eield electron emission microscopy SIMS Secondary ion mass spectra... 

Wagner, M.S., Graham, D.J., Ratner, B.D., Castner, D.G. (2004) Maximizing information obtained from secondary ion mass spectra of organic thin films using multivariate analysis. Surf Set, 570, 78-97. 

Worley, C.G, Enriquez, E.P, Samulski, E.T., Linton, R.W. (1996) Effects of polypeptide conformation and surface bonding on static secondary ion mass spectra. Surf. Interface Anal., 24, 59-67. 

Vanden Eynde, X., Bertrand, R, Dubois, R, Jerome, R. (1998) Influence of end group and molecular weight on polybutadiene fingerprint secondary ion mass spectra. Macromolecules, 31,6409-6416. 

Positive, secondary ion mass spectra of SIBS polymer containing taxol recorded using Ga+ ions and Ceo ions under static conditions are shown in Figure 46.23. The (M -1- H) ion from taxol is not observed while the contribution of polydimethyl siloxane (PDMS), which is innate to the polymer formulation, is quite significant with Ga+ ions. The molecular ions of taxol and higher mass fragments are enhanced using Ceo primary ions. 

FIGURE 46.23 Positive, secondary ion mass spectra of SIBS polymer containing paclitaxel (PTx). Data were recorded using Ga ions (lower spectrum) and Ceo ions (upper spectrum) under static conditions. 

Stanley, M.S. and Busch, K.L. 1987. Positive secondary-ion mass spectra and thin-layer chromatography-mass spectrometry of phenothiazine drugs. Anal. Chim. Acta, 194 199-209. 

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