Thin-layer chromatographic screening of amino acids in plasma and urine of newborns.

We describe a simple, rapid, and inexpensive unidimensional high-resolution thin-layer chromatographic procedure for screening for aminoacidopathies in newborns. Protein-free filtrates are prepared for ultrafiltration of as little as 10 z1of plasma. A rapid, inexpensive photographic method provides large, high-contrast pictures of the chromatograms for permanent records. A day’s samples can be completed in 3 h, including all phases of the procedure.