[Assay of carbromal and its main metabolite (2-ethyl-butyryl-urea) in biological fluids (author's transl)].

The materials mentioned above are reextracted from an ether solution by 2 N sodium hydroxide. The UV extinction of the aqueous layer at 232 nm and 30 degrees C is followed by means of a slave recorder. The original extinction is found by back-extrapolating to the time of re-extraction. It has to be corrected for the "biological matrix" by subtracting the extinction value after complete hydrolysis. Most interfering substances in the ether solution (carboxylic acids, barbiturates) may be removed previously by washing with aqueous buffers (pH 7.0 and 10.5).