Functionalized (SBA-C-18 and SM-C-18) and non-functionalized (SBA-15 and SM) mesoporous silicas were then examined as sorbents for solid-phase extraction of 17 beta-estradiol in aqueous media. Experiments were run in order to test critical factors affecting the procedure extraction efficiency, including the type of sorbent, the analyte concentration, the solvent and volume used for elution and the sample volume. Among the prepared materials, SBA-C-18 had the highest adsorption affinity towards 17 beta-estradiol and under optimized conditions (200 mg of sorbent, 150 mL of water sample, elution with 3 x 2 mL of methanol) this sorbent proved good extraction capacity and elution efficiency for this hormone from aqueous media (recovery near 100%). To evaluate the analytical applicability of the proposed method, it was applied to the determination of 17 beta-estradiol in drinking water by high performance liquid chromatography with a photodiode array detector. Calibration curves were shown to be linear between 1.25 and 100 mg L-1 with correlation coefficients >= 0.999 (n = 5) for 17 beta-estradiol. The instrumental detection and quantitation limits calculated were 0.38 and 1.25 mg L-1, respectively. The relative standard deviation obtained values were <= 3% and the mean recoveries obtained were of 82%. The results suggest that SBA-C-18 is a promising material for the off-line solid phase extraction of 17 beta-estradiol from waters. (C) 2013 Elsevier B.V. All rights reserved.