Publication Details (including relevant citation information):
IM Kempson, T Barnes, C Prestidge, Use of ToF-SIMS to study adsorption and loading behaviour of methylene blue and papain in a nano-porous silicon layer. Journal of the American Society of Mass Spectrometry, 21(2)254-260, 2010.
TOF-SIMS was applied to study the cross-sectional distribution of methylene blue and papain in porous silicon layers. Elemental and molecular information were used to study their distributions in the porous region and the chemistry of their adsorption. Methylene blue (MW = 284 Da) penetrated to the base to the pores. Positive ions (SiCH3+) suggest methylene blue binds to the substrate via its methyl groups. Negative fragments (SiOSH3- and SiO2SCH–) also suggested chemisorption via O bridging of the substrate Si and methylene blue S. The larger Papain molecule (23,406 Da) distributed itself in a similar manner to methylene blue demonstrating larger molecules can be effectively incorporated into such pore structures.
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