Fully-automated on-line solid phase extraction coupled to high-performance liquid chromatography–tandem mass spectrometric analysis at sub-ng/L levels of selected estrogens in surface water and wastewater

A fully-automated on-line solid phase extraction liquid chromatographic/electrospray ionization tandem mass spectrometric method for the analysis of estrone (E1), 17-β-estradiol (β-E2), 17-α-ethinylestradiol (EE2), 17-α-estradiol (α-E2) and estriol (E3) in surface water and wastewater was developed. The method showed a very good linearity from 250 ng/L down to compound specific quantification limits, which were included between 0.25 and 2.00 ng/L. These limits were obtained with 2.5 mL aliquots of injected sample and the total analysis time per sample was slightly less than 10 min. Under these conditions, detection limits were 0.15 ng/L for E1, 0.31 ng/L for β-E2, 0.52 ng/L for EE2, 0.59 ng/L for α-E2 and 0.95 ng/L for E3. The method reliability was tested on different kinds of real samples spiked with the estrogens, obtaining recoveries approximately included between 71 and 95%. The application to samples collected in rivers, lakes and wastewater treatment plants evidenced the presence of the investigated compounds at sub-ng/L or low ng/L concentration levels.

► A fully-automated on-line SPE-HPLC–MS/MS method for estrogen analysis is proposed.
► The total analysis time was less than ten minutes per sample.
► Detection limits in the sub-ng/L levels were achieved.
► A comparison with previous articles on the same object was presented.
► Estrogen concentrations in the analysed samples were in the sub- or low-ng/L levels.