Determination of estriol in serum during pregnancy
Estriol is present in serum mainly in form of its conjugates (16-glucuronide, 3-glucuronide, 3-sulfate and 3-sulfate-16-glucuronide).
Estriol is liberated from its conjugates by β-glucuronidase, extracted by solid phase, and derivatized with dansyl chloride. Following chromatography on silica gel with toluene – dioxane – methanol 8:2:1, it is determined quantitatively by fluorescence measurement.
The limit of quantification of this procedure is 2 µg/L estriol in serum. The results correlate outstandingly well with those obtained by radioimmunoassay (RIA).