Acta Phys. -Chim. Sin. ›› 1995, Vol. 11 ›› Issue (07): 617-621.doi: 10.3866/PKU.WHXB19950710

• ARTICLE • Previous Articles     Next Articles

The Determination of the Thermodynamic Functions of Protonation Reactions of Eight Kinds of Amino Acids by Titration Calorimetry

Liu Shi-Jun,Wang Cun-Xin,Wu Xu-Heng,Qu Song-Sheng   

  1. Department of Chemistry,Wuhan University,Wuhan 430072
  • Received:1994-05-05 Revised:1994-10-31 Published:1995-07-15
  • Contact: Wang Cun-Xin


The protonation reaction of eight kinds of amino acids-glycine, L-alanine, L-leucine, L-isoleucine, L-valine, L-phenylalanine, L-methionine, and L-tryptophan-at 298.15K and ionic strength I=0.1 (0.1 mol•dm-3 KNO3), have been studied by titration calorimetry. The thermodynamic functions of the protonation of these reactions were determined. The protonation of carboxyl group was studied by using nitric acid as titrant, and the protonation of amino group was studied by using imidazolium ion as titrant. The results are in good agreement with literature values.

Key words: Tiration calorimetry, Amino acid, Protonation reaction