Organic SIMS

Table I. Instrumental Requirements for Inorganic and Organic SIMS...

Organic SIMS, as the name Implies, deals with the sputtering and Ionization of organic molecules from surfaces. The ability to detect sputtered Ions of organic molecules was first reported by Bennlnghoven (8) who studied the emission of Intact amino add Ions... 

These areas should provide some exciting avenues to explore In the coming years for organic SIMS. 

Similar to Organic SIMS, inorganic surfaces are analyzable. The target surface can be the sample as in the tests described previously to determine the sensitive position and orientation of the target by observing the SIMS spectra of the stainless steel target. Other materials in the form of foils, powders or fabrics can be cemented to the target and bombarded by the beam from the FABMS gun. Several metals and ceramics were analyzed by this method. 

The emission of molecular ions in organic SIMS is discussed with respect to the method of ionization and the various sample preparation and matrix-assisted procedures used. The matrices include various solid-state and liquid matrices such as ammonium chloride, charcoal, glycerol, and galliun. A neutral beam source is described to analyze thick insulating films. Various chemical derivatization procedures have been developed to enhance the sensitivity of molecular SIMS and to selectively detect components in mixtures. 

Todd, P.J. et al., Organic SIMS of biologic tissue, Anal. Chem., 69, 529A, 1997. 

P. J. Todd, J. M. McMahon, R. T. Short, and C. A. McCandish, Organic SIMS of biologic tissues. Anal. Chem. 69, 528A-535A (1997). 

B. J. (2000) A theoretical investigation of the yield-to-damage enhancement with polyatomic projectiles in organic SIMS. / Phys ChemB, 104,8221-8228. 

Hagenhoff [145] has given a quantitative description of organic SIMS. Various strategies for quantification have been developed internal standards (limited applicability, because of elaborate preparational steps mostly in liquid phases), univariate and multivariate quantification. In the latter cases quantification is achieved by normalisation to uncharacteristic peaks e.g. hydrocarbons), to a sum of characteristic peaks e.g. in mixtures) or to the overall spectral intensity. Promising results concerning quantification of SIMS data can be obtained by evaluation of peak intensity ratios and by means of multivariate statistical methods. Using internal standards an accuracy of the quantification of better than 10% can be reached [146]. 

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