Two-dimensional paper chromatographic determination of amino acids in urine.

DENT (1) introduced paper chromatography for tile ilivestigatioll of amino-aciduria in 1948. However, his one-dimensional system yielded inadequate separation, and his two-dimensional method required 3 days. Since then, technics utilizing gas chromatography (2-4), thin layer chromatography, column chromatography, and high voltage electrophoresis (5-7) have been published for tile determination of amillo acids in urine. All of these methods exhibit good resolution and permit quantitation. However, they suffer from either a need of costly equipment or extreme consumption of time. Consequently, they are not practical for screening large numbers of samples. The ever-increasing demands made upon our laboratory for urinary amino acids resulted in the development of a rapid, reliable, twodimensional paper chromatography method for sorting out Specimens requiring more extensive investigation. In order to obtain good resolution with this procedure, desalting the urine prior to chromatography is absolutely essential. For this purpose, tile Tobal desalter (Model CD-i), which utilizes an anion-cation exchange membrane with sodium hydroxide and sulfuric acid as electrolytes, was found to be most effective. Desalting is carried out at three pH levels-5, 7, and 8. This pi’ocesss’rves to purify the urine from some extraneous material and Frommi the Dept. of Pathology, 1thod Eslamid Hospital, F’rovidemtce, RI 02902. The author wishes to txjress his appreciation to Mrs. Laura Olson and Mrs. Ramnila Shah for their technical assistance. Received for publication July 12, 1968; accepted for pimbhation Feb 3, 1969.