Agriculture Reference
In-Depth Information
Table 5.1. Ion-Selective Electrodes and Their Characteristics
Electrode/Ion
a
Type
Molar Range
a
Interferences
a
Ammonia
Gas sensing/combination
1.0-5 ¥ 10
-7
Volatile amines, Hg
+
Bromide
Solid state
1.0-5 ¥ 10
-5
S
2-
must not be present; CN
-
,
I
-
,NH
3
,Cl
-
,HO
-
Cadmium
Solid state/combination
10
-1
-10
-7
Pb
2+
,Hg
2+
,Cu
2+
Calcium
Half-cell
1.0-5 ¥ 10
-7
Na
+
,Pb
2+
,Fe
2+
,Cu
2+
, H
+
Carbon dioxide
Gas sensing
3 ¥ 10
-2
-10
-5
Volatile organic acids
Lead
Solid state/half-cell
0.1-10
-6
Cu
2+
,Ag
+
,Fe
3+
,Cd
2+
,Ag
+
Nitrate
Half-cell
1.0-7 ¥ 10
-6
ClO
-
,I
-
, ClO
-
,CN
-
,Br
-
,
NO
-
,HS
-
,CO
2-
, HCO
-
,Cl
-
Nitrogen oxide
Gas sensing/combination
5 ¥ 10
-3
-3.6
¥ 10
-6
CO
2
, volatile weak acids
Oxygen
Gas sensing/combination
0-20 ppm
—
Perchlorate
Half-cell
1.0-7 ¥ 10
-6
I
-
,NO
-
, ClO
-
,NO
-
,CN
-
,
NO
-
, HCO
-
,CO
2-
,Cl
-
Potassium
Half-cell
1.0-10
-6
Cs
+
,Na
+
,NH
+
,H
+
Redox/ORP
Combination
—
—
Sodium
Half-cell
Saturated to 10
-6
Ag
+
,K
+
,H
+
,Li
+
,Cs
+
,Tl
+
a
This is not an exhaustive list of ISE electrodes or number of interferences. Also, manufacturers' specifications must be consulted as different materials
and construction may result in different interferences and sensitivities.
