Detection of estrogen-like compounds by thin-layer chromatography.

There are different national food regulations concerning the use of hormoneactive substances in the breeding of domestic animals that serve as human food. This situation requires specific and sensitive methods for the detection of any residues in food. The hormones used in practice can be determined with improved sensitivity by coupling to the diazonium compound Fast Dark Blue R Salt. After thin-layer chromatography on high-performance thin-layer chromatographic plates with two different solvent mixtures, zeranol, estradiol, estriol and estrone are analysed as azo dyestuffs. The detection limit of these hormones is below 10 ng.

[Substrate specifity of "cholesteroloxidase" for the enzymatic determination of cholesterol]. / Zur Spezifität der "Cholesterinoxydase" für die enzymatische Cholesterinbestimmung

The substrate specifity of "Cholesteroloxidase" (E.C.1.1.3.6) from Nocardia erythropolis was studied. The main sterols from animal and plant fats and 4-methylsterols as well as one triterpene served as substrates. The enzyme is not specific for cholesterol but also reacts with all the natural 3 beta-hydroxysterols. However, the enzymatic reaction may contribute as a new analytical method to determine the "total sterols" in the unsaponifiable matter of fats.