[Deterimination of aldosterone in urine and plasma (author's transl)]

The method described permits an exact and rapid determination of aldosterone in urine and plasma. The reliability of the method is based on the separation of aldosterone from contaminating steroids by thin-layer chromatography. The mobile phase used was: cyclohexane--ethyl acetate (20:80). The steroids were extracted by dichloromethane. Plasma was extracted directly, and urine after hydrolysis with sulfuric acid (pH = 1). Recovery before radioimmunological analysis of aldosterone was 54.8 +/- 7.2 (S.D.)%(N = 40) for urine samples, and 39.1 +/- 4.4% (n = 60) for plasma samples. The coefficient of variation for multiple determinations of aldosterone was for urine 8.2% for low (n = 10) and 7.8% (n = 10). The sensitivity of the determination of aldosterone was for urine 0.04 microgram per 24-h volume (n = 10) and for plasma 4.4 ng per 100 ml (n = 10). The method avoids pitfalls due to the cross-reaction of anti-aldosterone serum with other materials.