Silver nanoparticles within the pore channels of selectively grafted mesoporous silica SBA-15 were synthesized. Silanols on the external surface of as-SBA-15 were first capped by -Si(CH(3))(3) groups. After removal of the template of capped SBA-15 by calcination, silanols on the internal surface of SBA-15 were modified by 3- aminopropyltrimethoxysilane (APTMS), and then formaldehyde was grafted by amino groups of APTMS, and further Ag(NH(3))(2)NO(3)SBA-15). High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy ( FTIR), nitrogen adsorption/desorption isotherms, and UV-vis spectra confirm that the silver nanoparticles have been confined inside the channels of SBA-15. In addition, the Ag-mSBA-15 modified electrode (Ag-mSBA-15/GC) exhibited an excellent electrocatalytic activity toward the reduction of hydrogen peroxide (H(2)O(2)). The proposed H(2)O(2) sensor exhibits a linear range of 48.5 mu M-0.97M with a detection limit of 12 mu M (S/N = 3) and analytical time of 10 seconds per sample. Copyright (c) 2008 Dong-Hai Lin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited