ISSN:
1572-8927
Schlagwort(e):
MES
;
TES
;
emf
;
standard potential
;
zwitterion
;
buffer solution
;
activity coefficients
;
dissociation constants
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract The equilibrium constants for the dissociation steps of (4-morpholineethanesulfonic acid) (MES) and (2-{[tris(hydroxymethyl)methyl]-1-ethanesulfonic acid (TES) have been determined at 12 and 7 different temperatures, respectively, from 5 to 55°C. The emf measurements were carried out by using a cell without liquid junction of the type: Pt; H2 (g, 1 atm) | buffer(m1), Na salt of buffer(m2), NaCl(m3) | AgCl, Ag. The pK 2 values of MES and TES at 25°C are 6.269 and 7.550. The thermodynamic quantities for the dissociation process have been calculated. These zwitterionic compounds are useful for pH control as standard buffers in the physiological region of pH 5.50 to 6.50 for MES, 6.5 to 7.5 for TES, respectively. Reliable measurements of the pH at isotonic saline solution (I = 0.16m) such as blood and plasma are important for clinical diagnosis.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1022937324983
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