We describe a mechanized method for determining total estrogens in plasma during the last trimester of pregnancy. This method involves rapid enzymic hydrolysis, automatic extraction (in a tube) with cyclohexane/ethyl acetate, purification of the extracted material by anion-exchange chromatography on a disposable “mini-column” of Dowex AG1 X 2 (acetate form), and continuous-flow fluorometric quantification. Conditions of hydrolysis and extraction were studied. The mean within-day imprecision (CV) was 7% and between-day imprecision was 8.1%. Sensitivity was 75 nmol/L of plasma. Results are obtained in 4 h. The technique is quite suitable for routine determinations: 90 assays can be done by a team of three technicians in one working day.
We describe a new method of extraction and purification of estrogens in low concentration in urine, involving a rapid enzymic hydrolysis of a 10-mL sample, automatic extraction (in a tube) with CHCl3/ethyl acetate, purification by chromatography on a disposable "mini-column" of AG 1-X2, and fluorometry by continuous flow according to Itrich's procedure [Acta Endocrinol. (Copenhagen) 35, 34 (1960)]. Conditions of hydrolysis, extraction, and purification were studied. Within-day precision (CV) was 7.5%, the mean between-day precision 8.5%. The sensitivity was 6 microgram of total estrogens per liter of urine. The specificity was assessed particularly by comparison with the results obtained by Schöller et al. [Acta Endocrinol. (Copenhagen) 57, suppl. 107 (1966)] and by gas-chromatography-mass-spectrometry. The normal limits as calculated by this technique were identical to values reported by others. The technique is rapid; results are obtained in 3 h. It is quite suitable for routine determinations: 100 assays can be done by a team of three technicians in one working day.
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