Hanna Instruments HI 4211 - Manual (Page 56)

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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 = ½).
Example 2
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.
ΔE - 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
SAMPLE
- the sample concentration;
C
STD
- the standard concentration;
V
SAMPLE
- the sample volume;
V
STD
- the standard volume;
and V
T
= V
SAMPLE
+ V
STD
where: C
SAMPLE
- the sample concentration;
C
STD
- the standard concentration;
V
SAMPLE
- the sample volume;
V
STD
- the standard volume;
and V
T
= V
SAMPLE
+ V
STD
ΔE - the difference of potential from the electrode;
S - the electrode slope, determined in a
previous calibration;
f
- the stoichiometric ratio between sample
and standard;