Ion exchange chromatography which helps in the separation of charged molecules such as amino acids based on their affinity to the ion exchanger is a useful method employed in the separation of amino acids. High-performance liquid chromatography is another medium that employs an adsorbent material that is made to pass through a solvent that would eventually result in the separation of the different components of the substance being measured.
Quantitation of the amino acids beyond 10nmol is done using the ninhydrin reaction which gives off different colours depending on the amount of the amino acid. Phenyl isothiocyanate is used in the evaluation of secondary amines and is a reagent that is added to the solid phase in the HPLC test.
I believe the experiment was too see if the flowers that would grow from the stem would turn out to be red in color. (Which is the reason they put red ink.)
