Analysis by Dansylation of Amino Acids Dissolved in Marine and Freshwaters1

Dissolved amino acids in seawater, pond water, and spent algal media have been qualitatively analyzed by dansylation, extraction, and thin‐layer chromatography. The amino acids were dansylated directly following adjustment of the p H of the samples, and at least 1,000‐fold concentration was achieved by using diethyl ether to extract the amino acid derivatives, which were then applied to thin‐layer plates and chromatographed in two dimensions. Analyses revealed aspartic acid to be present in all samples; the other amino acids most frequently found were serine, glycine, alanine, and arginine. Additional amino acids, peptides, and several unidentified spots were also observed.