Ion Exchange and Thin Layer Chromatographic Separation and Identification of Amino Acids in a Mixture: An Experiment for General Chemistry and Biotechnology Laboratories

• Autores: Linda S. Brunauer, Katelyn E. Caslavka, Karinne Van Groningen
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 91, Nº 12, 2014, págs. 2216-2220
• Idioma: inglés
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• Resumen

  • A multiday laboratory exercise is described that is suitable for first-year undergraduate chemistry, biochemistry, or biotechnology students.

    Students gain experience in performing chromatographic separations of biomolecules, in both a column and thin layer chromatography (TLC) format.

    Students chromatographically separate amino acids (AA) in an unknown mixture using a small column of Dowex-50 resin. The AA elution profile is determined by graphical analysis of a rapid ninhydrin microplate spectrophotometric assay that converts the colorless AA into colored ninhydrin derivatives.

    Column fractions corresponding to elution �peaks� are further analyzed by TLC on silica gel plates alongside AA standards. Visualization of AA migration on TLC is accomplished with a ninhydrin dipping protocol. Students use their chromatography data, structural information about the resin and the various AA, and their knowledge of intermolecular attractions and acid-base chemistry to determine the identity of the AA in their unknown mixture.