A simple near-IR transmission spectroscopy method for the determination of percent carbon coverage in trimethylsilylated silicas has been developed. The alkylated silica is slurried in carbon tetrachloride, a solvent with a similar refractive index to silica, to reduce light scattering. Percent carbon is then determined by measuring either the peak height or peak area ratio of the peak at 1180 nm (due to the second overtone of the C-H stretch) to the peak at 1385 nm (due to the overtone of the SiO-H stretch). Comparison with results from elemental analysis permits construction of a correlation curve that can then be used to determine % carbon in unknown samples.