Interfering Ions - Horiba Scientific LAQUAtwin B-74 Series Manual

8.3

Interfering ions

Target
+
K
1 × 10
Ba
Ca
1 × 10
+
Li
Interfering
1 × 10
ions and
selectivity
Cs
coefficients
3 × 10
NH
6 × 10
(at 10
Na
3 pH to 9 pH
pH range (at 10
Na
Selectivity coefficient is a concentration ratio of the interfering ion against the
target ion, which affects the target ion measurement value. For example,
selectivity coefficient of potassium ion against sodium ion is 1 × 10
means for the same concentration of potassium ion and sodium ion
coexisting in a sample, the sodium measurement shows approximately 1 ×
-2
10 (1%) higher result.
Sodium
ion
+
(Na )
+
, Rb Rb
：
-2
1 × 10
2+ 2+
, Sr , Mg
2+ 2+
, Mg 1 × 10
：
-4
NH
：
7 × 10
-3
Ca
+
：
7 × 10
-3
Cs
+
：
4 × 10
4
-3
Na
-3
mol/L 3 × 10
+
) (at 10
K
2 pH to 9 pH
-3
mol/L (at 10
+
) K
Potassium
ion
+
(K )
+
：
-1
2+
：
-5
+
：
4
-3
2+
：
-7
+
：
-3
+
：
-4
-3
mol/L
+
)
-3
mol/L
+
)
32
Nitrate
ion
-
(NO )
3
-
I
：
10
-
Cl
：
-2
4 × 10
-
Br
：
-1
9 × 10
-
ClO
：
4
-3
3 × 10
-
NO
：
2
-1
7 × 10
-3
(at 10 mol/L
-
NO )
3
3 pH to 8 pH
-3
(at 10 mol/L
-
NO )
3
Calcium
ion
2+
(Ca )
+ + 2+
Na , K , Mg
：
-3
1 × 10
2+ 2+
Fe , Zn
：
1
3+
Fe
：
10
2+
Cu
：
-2
1× 10
-3
(at 10 mol/L
2+
Ca )
4 pH to 12 pH
-3
(at 10 mol/L
2+
Ca )
-2
, which