The Reaction between Mercury(II) and Organic Compounds. IV. A Photometric Method for the Determination of Basic Amino Acids Precipitated with a Mercury(II) Perchlorate Precipitant and Some Properties of Their Products

The particular reactivity of basic amino acids in presence of mercury(II) perchlorate gives white amorphous products (by X-ray powder diffraction). The structures of the products may be considered to be [Arg-Hg]ClO4·Hg(ClO4)2, [His-Hg]ClO4·Hg(ClO4)2 and [Lys-Hg]ClO4·Hg-(C1O4)2 on the bases of elemental analytical data and of infrared patterns showing the absorption bands of νas(Hg–O), ν(Hg–N) and perchlorate ions. The applicability of this peculiar reactivity to the separation and photometric determination of basic amino acids has been studied. The above mentioned products were obtained selectively as a mixture from a mixture of about twenty kinds of amino acids. The isolation of the mixture into each product could be performed satisfactorily by utilizing the different solubilities of the products in 10 N acetic acid containing sodium or potassium chloride (3.3 W/V %), and in an aqueous sodium hydroxide solution. Although the products showed characteristic ultraviolet absorption curves differing from thos...