Applicability of micellar electrokinetic chromatography to the analysis of estrogens in water

Estrone, beta-estradiol and ethynylestradiol spiked in water were extracted using solid-phase extraction (SPE) and then directly determined by micellar electrokinetic chromatography (MEKC) with online concentration (sweeping). A 350 mL original sample volume (10 nM each) was concentrated to 1 mL using SPE, and ca. 240 nL of this solution was injected onto an MEKC capillary column. After sweeping, the estrogen related compounds were detected using a commercial absorbance detection system with an LOD of 0.16-0.30 nM in the original sample.