Electrochemical detector for high-performance liquid chromatography. III. Determination of estriol in human urine during pregnancy.

Abstract
The excretion of estrogens, mainly estriol (E3), into the urine increases steadily during normal pregnancy, and abnormal excretion of estrogens can occur due to placenta malfunction. It is important in the clinical control of pregnancy to assay the urinary E3 concentration. High-performance liquid chromatography [HPLC] combined with electrochemical detection [ECD] was applied for the determination of E3 in human urine obtained during pregnancy. Estrogens were extracted with ether, chromatographed on a reversed-phase C-18 column with a mobile phase of methanol-water-perchloric acid mixture, and detected electrochemically at 1.1 V vs. Ag/AgCl. The minimum detectable quantity of estriol was 10 ng. Within-run precision was better than 3% for the whole procedure.