ing only the time to prepare the porous silicon, within minutes, or to acquire a
previously etched substrate from storage. Chemical modifications of the substrates
can stabilize the surfaces against degradation and modulate the interfacial properties to control deposition, desorption, and ionization of target analytes. Considering the availability of reactions for the modification of porous silicon surfaces, tailoring a DIOS-MS substrate for the optimal characterization of a particular analyte
could well be accomplished through chemical manipulation.
Fig. 16.19. Mass spectrometry of WIN
antiviral drug. (a) DIOS-MS spectrum of WIN
deposited upon porous silicon. Inset: DIOSPSD-MS spectrum of WIN. (b) MALDI-MS
spectrum of WIN dispersed in a-cyano-4hydroxycinnamic acid (HCCA). (c) Attempted
desorption/ionization from WIN deposited
upon gold MALDI plate, illustrating the
necessity of the matrix for successful spectrometry. (Reprinted with permission from
[127]. Copyright 1999 Nature Publishing
Group.)
16 Recent Developments in the Chemistry and Chemical Applications of Porous Silicon
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