100
101
pH BUFFER TEMPERATURE DEPENDENCE
Temperature has an effect on pH. The calibration buffer solutions are affected by temperature changes to a
lower degree than normal solutions.
During calibration, the instrument will automatically calibrate to the pH value corresponding to the measured
or set temperature.
During calibration, the instrument will display the pH buffer value at 25 °C.
P
M
E
T
S
R
E
F
F
U
B
H
p
C
°
K
°
F
°
9
7
6
.
1
0
0
0
.
3
0
1
0
.
4
2
6
8
.
6
0
1
0
.
7
7
7
1
.
9
0
1
0
.
0
1
4
5
4
.
2
1
0
3
7
2
2
3
0
7
6
.
1
2
7
0
.
3
7
0
0
.
4
2
8
9
.
6
0
3
1
.
7
9
5
4
.
9
6
1
3
.
0
1
9
7
3
.
3
1
5
8
7
2
1
4
0
7
6
.
1
1
5
0
.
3
2
0
0
.
4
9
4
9
.
6
8
9
0
.
7
1
9
3
.
9
5
4
2
.
0
1
8
7
1
.
3
1
0
1
3
8
2
0
5
1
7
6
.
1
3
3
0
.
3
0
0
0
.
4
1
2
9
.
6
0
7
0
.
7
8
2
3
.
9
0
8
1
.
0
1
5
8
9
.
2
1
5
1
8
8
2
9
5
3
7
6
.
1
9
1
0
.
3
1
0
0
.
4
7
9
8
.
6
6
4
0
.
7
3
7
2
.
9
8
1
1
.
0
1
9
9
7
.
2
1
0
2
3
9
2
8
6
5
7
6
.
1
8
0
0
.
3
4
0
0
.
4
8
7
8
.
6
7
2
0
.
7
2
2
2
.
9
2
6
0
.
0
1
1
2
6
.
2
1
5
2
8
9
2
7
7
9
7
6
.
1
0
0
0
.
3
0
1
0
.
4
2
6
8
.
6
0
1
0
.
7
7
7
1
.
9
0
1
0
.
0
1
0
5
4
.
2
1
0
3
3
0
3
6
8
3
8
6
.
1
5
9
9
.
2
7
1
0
.
4
1
5
8
.
6
8
9
9
.
6
7
3
1
.
9
2
6
9
.
9
6
8
2
.
2
1
5
3
8
0
3
5
9
8
8
6
.
1
1
9
9
.
2
6
2
0
.
4
2
4
8
.
6
9
8
9
.
6
8
0
1
.
9
9
1
9
.
9
8
2
1
.
2
1
0
4
3
1
3
4
0
1
3
9
6
.
1
0
9
9
.
2
7
3
0
.
4
7
3
8
.
6
3
8
9
.
6
9
6
0
.
9
1
8
8
.
9
8
7
9
.
1
1
5
4
8
1
3
3
1
1
0
0
7
.
1
0
9
9
.
2
9
4
0
.
4
4
3
8
.
6
9
7
9
.
6
0
4
0
.
9
7
4
8
.
9
4
3
8
.
1
1
0
5
3
2
3
2
2
1
7
0
7
.
1
1
9
9
.
2
2
6
0
.
4
4
3
8
.
6
8
7
9
.
6
4
1
0
.
9
7
1
8
.
9
7
9
6
.
1
1
5
5
8
2
3
1
3
1
5
1
7
.
1
3
9
9
.
2
6
7
0
.
4
6
3
8
.
6
9
7
9
.
6
0
9
9
.
8
3
9
7
.
9
6
6
5
.
1
1
0
6
3
3
3
0
4
1
4
2
7
.
1
5
9
9
.
2
1
9
0
.
4
9
3
8
.
6
2
8
9
.
6
9
6
9
.
8
3
7
7
.
9
2
4
4
.
1
1
5
6
8
3
3
9
4
1
4
3
7
.
1
8
9
9
.
2
7
0
1
.
4
4
4
8
.
6
7
8
9
.
6
8
4
9
.
8
7
5
7
.
9
3
2
3
.
1
1
0
7
3
4
3
8
5
1
4
4
7
.
1
0
0
0
.
3
3
2
1
.
4
0
5
8
.
6
3
9
9
.
6
9
2
9
.
8
6
4
7
.
9
1
1
2
.
1
1
5
7
8
4
3
7
6
1
5
5
7
.
1
2
0
0
.
3
9
3
1
.
4
7
5
8
.
6
1
0
0
.
7
0
1
9
.
8
0
4
7
.
9
4
0
1
.
1
1
0
8
3
5
3
6
7
1
7
6
7
.
1
3
0
0
.
3
6
5
1
.
4
5
6
8
.
6
0
1
0
.
7
1
9
8
.
8
8
3
7
.
9
3
0
0
.
1
1
5
8
8
5
3
5
8
1
0
8
7
.
1
2
0
0
.
3
2
7
1
.
4
3
7
8
.
6
9
1
0
.
7
1
7
8
.
8
0
4
7
.
9
8
0
9
.
0
1
0
9
3
6
3
4
9
1
3
9
7
.
1
0
0
0
.
3
7
8
1
.
4
0
8
8
.
6
9
2
0
.
7
1
5
8
.
8
8
4
7
.
9
9
1
8
.
0
1
5
9
8
6
3
3
0
2
7
0
8
.
1
6
9
9
.
2
2
0
2
.
4
8
8
8
.
6
0
4
0
.
7
9
2
8
.
8
9
5
7
.
9
4
3
7
.
0
1
∆
E
- the difference of potential from the electrode;
S
- the electrode slope, determined in a previous
calibration;
f
- the stoichiometric ratio between sample and
standard;
where:
C
SAMP
- the sample concentration;
C
STD
- the standard concentration;
V
SAMP
- the sample volume;
V
STD
- the standard volume;
V
ISA
- ISA volume
where:
C
SAMP
- the sample concentration;
C
STD
- the standard concentration;
V
SAMP
- the sample volume;
V
STD
- the standard volume;
V
ISA
- ISA volume;
∆
E
- the difference of potential from the electrode;
S
- the electrode slope, determined in a previous
calibration;
f
- the stoichiometric ratio between sample and
standard;
Example 1
You have sulfide samples and you are adding
Ag
+
. The reaction is:
One mole sulfide sample reacts with 2 moles silver standard (
f
=
1
/
2
).
Example
You have sulfide samples and you are adding
Pb
2+
. The reaction is:
One mole sulfide sample reacts with 1 mole lead standard (
f
= 1).
Analyte Addition and Analyte Subtraction
Analyte Addition and Subtraction are variations of the previous two methods.
With Analyte Addition,
sample (analyte) is added
to an Ion standard being measured. The standard and
sample contain the same ion. mV are taken before and after the sample addition. From the mV the analyte
concentration is determined.
With Analyte Subtraction,
sample (analyte) is added to an Ion standard
being measured. The analyte reacts
with the measured Ion in a known manner thus removing measured ions from the solution. From the change
in mV the concentration of the analyte is determined.
S
2-
+ 2
Ag
+
→
Ag
2
S
S
2-
+
Pb
2+
→
PbS
C
SAMP
=
C
STD
·
V
STD
·
(
V
STD
+
V
SAMP
+
V
ISA
)·10
∆
E
-
(
V
STD
+
V
ISA
)
(
V
STD
+
V
ISA
)
V
SAMP
S
C
SAMP
=
f
·
{
(
V
STD
+
V
ISA
)
-
[
1 +
(
V
STD
+
V
ISA
)
]
·10
∆
E
}
·
(
C
STD
·
V
STD
)
V
SAMP
V
SAMP
V
STD
+
V
ISA
S
w
w
w
.
.c
om
in
fo
rm
at
io
n@
itm
.c
om
1.
80
0.
56
1.
81
87
