Table 16–5: Potential of the Ag/AgCl reference electrode; dE is the potential difference
with EAg/AgCl in saturated KCl (continued)
Cl
-
(mmol/L)
E
Ag/AgCl
dE (mV)
a
10
338
148
8.0
344
154
6.0
351
161
4.0
361
171
2.0
379
189
1.0
396
206
0.5
414
224
a. Rounded to the nearest whole number
The addition of chloride to the mobile phase has a few restrictions. For example, the ISAAC is not
recommended at a high working potential (> 1.2 V vs. Ag/AgCl in 2 mmol/L KCl) because Cl- is
oxidized and contributes to the background current. In ion chromatography, the addition of Cl-
may lead to undesired chromatographic changes. With a silver working electrode, the addition of
Cl- to the mobile phase causes formation of an AgCl coating on the working electrode, leading to
inactivation. At high pH or high modifier concentrations, the ISAAC is less suitable and a HyREF
is recommended.
December 16, 2021, 715007395 Ver. 00
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