Adsorption of silanes bearing nitrogenated Lewis bases on SiO2/Si (100) model surfaces.
The present paper describes the one-pot procedure for the formation of self-assembled thin films of two silanes on the model oxidized silicon wafer, SiO2/Si. SiO2/Si is a model system for other surfaces, such as glass, quartz, aerosol, and silica gel. MALDI-TOF MS with and without a matrix, XPS, and AFM have confirmed the formation of self-assembled thin films of both 3-imidazolylpropyltrimethoxysilane (3-IPTS) and 4-(N-propyltriethoxysilane-imino)pyridine (4-PTSIP) on the SiO2/Si surface after 30 min. Longer adsorption times lead to the deposition of nonreacted 3-IPTS precursors and the formation of agglomerates on the 3-IPTS monolayer. The formation of 4-PTSIP self-assembled layers on SiO2/Si is also demonstrated. The present results for the flat SiO2/Si surface can lead to a better understanding of the formation of a stationary phase for affinity chromatography as well as transition-metal-supported catalysts on silica and their relationship with surface roughness and ordering. The 3-IPTS and 4-PTSIP modified SiO2/Si wafers can also be envisaged as possible built-on-silicon thin-layer chromatography (TLC) extraction devices for metal determination or N-heterocycle analytes, such as histidine and histamine, with "on-spot" MALDI-TOF MS detection.
Andresa
Juliana Salvador
JS
Universidade de São Paulo, Instituto de Química de São Carlos, P.O. Box 780, 13564-970 São Carlos, Brazil.
Reis
Rafael Machado
RM
Gonzalez
Eduardo Perez
EP
Santos
Leonardo Silva
LS
Eberlin
Marcos Nogueira
MN
de Paula Nascente
Pedro Augusto
PA
Tanimoto
Sonia Tomie
ST
Machado
Sérgio Antônio Spínola
SA
Rodrigues-Filho
Ubirajara P
UP