Improved liquid chromatographic determination of placental estriol in urine

Placental estriol in urine can be determined, after enzymatic hydrolysis, by liquid chromatography. A single-step extraction technique results in rapid processing with minimal sample manipulation. Analytical recovery of estriol added to urine was 96 to 106%. Day-to-day precision (CV), established by 10 replicate analyses at a mean concentration of 15.9 mg of estriol per liter, was 3.7%.