A selective and sensitive method was developed for the determination of estrogens and bisphenol A by high-performance liquid chromatography with electrochemical detection. A mixing solution consisting 45 vol% acetonitrile and 55 vol% water containing 0.07 mol l
−1 sodium perchlorate at pH 2.7 was used as a mobile phase. The electrolytic oxidation of estrogens and bisphenol A was performed on a glassy carbon working electrode at 1.05 V
vs. Ag/AgCl. The calibration curves (peak area vs. concentration) were linear (correlation coefficient≥0.999) in the range from 10 ng ml
−1 to at least 1000 ng ml
−1, and passed through the origin with a relative standard deviation of 0.6 to 2% for 100 ng ml
−1 (
n = 5). This method was applied to the simultaneous determination of these compounds at ng l
−1 level in river water and the discharge water of a sewage treatment plant. Interference from humic compounds could be avoided by using a clean-up technique with a 45 vol% methanol solution at pH 9 to 10, and a stable background current was obtained. The detection limits calculated from the
S/
N ratio (
S/
N = 3) were
ca. 5 ng l
−1. The time required for an analysis after solid-phase extraction was within 40 min. The proposed method without any troublesome and time-consuming pretreatment process, such as derivatization, is more simple and rapid compared with conventional methods.
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