Separation of Pyridine Mono-Carboxylic Acids on Paper Chromatograms


CHEMICAL methods using cyanogen bromide and aromatic amines1–3 (König reaction) and an acid-indicator4 for the detection of pyridine carboxylic acids on paper chromatograms have been reported. But the toxic character of cyanogen bromide causes difficulty; and it has been observed that good spots with acid-indicator are often not produced, particularly when the acid concentration is very low. A very convenient method has been found for detecting these acids on the filter paper by spraying with a solution containing cupric ions followed by benzidine; also their efficient separation from the mixture has been achieved.

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  1. 1

    Huebner, C. F., Nature, 167, 119 (1951).

  2. 2

    Kodicek, E., and Reddi, K. K., Nature, 168, 475 (1951).

  3. 3

    Leuschner, F., Naturwiss., 40, 554 (1954).

  4. 4

    Hashizume, T., Nature, 173, 645 (1954).

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