Open AccessThe principle of formaldehyde, alcohol, and acetone titrations. With a discussion of the proof and implication of the zwitterion conception
Author(s) -
George Maxwell Richardson
Publication year - 1934
Publication title -
proceedings of the royal society of london. series b, containing papers of a biological character
Language(s) - English
Resource type - Journals
eISSN - 2053-9185
pISSN - 0950-1193
DOI - 10.1098/rspb.1934.0032
Subject(s) - zwitterion , titration , formaldehyde , chemistry , argument (complex analysis) , acetone , titration curve , alcohol , epistemology , philosophy , organic chemistry , molecule , biochemistry
Consideration of the implications of the zwitterion hypothesis of Bjerrum (1923) makes it desirable to state afresh the principles underlying the methods commonly employed in the titration of amino-acids. Deductions of considerable theoretical importance,cf., e. g ., Calvery (1933) are still being made on the supposition that the alkalimetric formaldehyde titration method of Sørensen (1907) and the corresponding alcohol method of Foreman (1920) and of Willstätter and Waldschmidt-Leitz (1921) estimate the carboxyl groups of amino-acids whilst the acidimetric acetone titration of Linderstrøm-Lang (1928) estimates the amino-groups. Yet the zwitterion hypothesis indicates that this assumption is the reverse of the truth. Discussion is greatly facilitated by collective consideration of recent physico-chemical evidence clarifying the principles upon which these common bio-chemical methods rest. In a recent discussion of two of the titrimetric methods (Van Slyke and Kirk, 1933) the existence of this evidence is ignored, so that it becomes necessary to systematize and elaborate the empirical argument of these authors in the light of the relevant investigations of Grünhut (1919), Cray and Westrip (1925), Michaelis and Mizutani (1925), Birch and Harris (1930,b ), and Levy (1933). At the same time new and useful developments are indicated.