On the determination of ethanolamine in urine and the factors affecting its daily output.

Methods for the detection and quantitative determination of ethanolamine in animal tissues and fluids have, with few exceptions, been focused upon phospholipide hydrolysates. They include the gold salt method of Trier (l), the CaO-ether extraction method of Thierfelder and Schulze (Z), isolation as the diiodosalicylate (Stetten (3)), and the periodate oxidation method employed by Artom (4). In so far as urine is concerned Dent has employed for qualitative purposes two-dimensional paper chromatography (5, 6) followed by the ninhydrin reaction; for confirmatory purposes ethanolamine was isolated as the di-p-nitrobenzoyl derivative after displacement from Zeo-Karb 215 (6); for quantitative purposes direct periodate oxidation of the urine was employed (6). Ion exchange chromatography and the ninhydrin reaction have been further exploited in the elegant method of Stein (7) for the comprehensive analysis of urine. Fishman and Artom (8) have applied periodate oxidation, combined with Permutit adsorption of bases, direct’ly to urine in a procedure for the estimation of serine and ethanolamine. Our experience with a closely comparable method for the determination of ethanolamine leads us to conclude that this direct method is lacking in specificity and yields results that are too high. In a search for a highly specific method, applicable to urine, we turned to chromatography of the dinitrophenyl derivatives of the bases. The quantitative separation of dinitrophenylethanolamine was achieved without difficulty and the quantity isolated was determined spectrophotometritally.