PDF file - Facultatea de Chimie şi Inginerie Chimică

ocp / V vs. SCE
ocp / V vs. SCE
0.1
0.0
-0.1
Arginine
SIMONA VARVARA, MARIA POPA, LIANA MARIA MURESAN
-0.2
0 900 1800
time / s
2700 3600
0.06
0.05
0.04
0.03
0.02
0.01
0.00
Methionine
-0.01
0 900 1800
time / s
2700 3600
ocp / V vs. SCE
-0.2
0 900 1800
time / s
2700 3600
The value of the shift in the Ess is related to the structure of the amino
acid and its concentration in the electrolyte. Thus, for Cys and Arg the maximum
negative shifts occur at concentrations of 1 mM and 10 mM, respectively.
238
ocp / V vs. SCE
0.1
0.0
-0.1
0.1
0.0
-0.1
-0.2
-0.3
Histidine
Cysteine
-0.4
0 900 1800
time / s
2700 3600
Figure 1. Variation of the open-circuit potential in time for bronze electrode
after immersion in the corrosive media in the absence and in the presence
of amino acids at different concentrations of amino acids (mM):
() 0; (― ―) 0.01; (·····); 0.1; (―·―) 1; (―··―) 10.
The values of Ess obtained in the presence of different concentrations
of amino acids are presented in Table 1.
Table 1. The values of the steady-state potential of bronze in electrolytes
containing different concentrations of amino acids
Amino acids
conc. (mM)
Glu His
E ss / mV vs. SCE
Arg Met Cys
0.01 +47.11 - +32.71 +40.10 +35.93
0.1 +45.48 +19.78 +28.54 +22.17 -11.77
1 +26.72 + 7.56 -73.43 - 5.33 -13.33
10 - -17.95 -177.51 - -327.60