A151 Benchtop Conductivity Meter
20
Addendum 1: Preparation of Conductivity Standard Solutions
Place AR potassium chloride reagent in a 50ml beaker and dry in an oven for 3 to 5 hours at 105° C, then cool to room temperature in desiccator.
CALIBRATION SOLUTIONS
REAGENT
84µ S/cm
Accurately weigh out 42.35mg of KCL and dissolve in 1 litre deionised water.
1413µ S/cm
Accurately weigh out 745.9mg of KCL and dissolve in 1 litre deionised water.
12.88mS/cm
Accurately weigh out 7.45g of KCL and dissolve in 1 litre deionised water.
111.8mS/cm
Accurately weigh out 74.5g of KC, and dissolve in 1 litre deionised water.
Stir the solution until the reagent has thoroughly mixed. Preparation is completed.
Addendum 2: How to calculate the temperature coefficient
To determine the temperature coefficient of sample solution use the formula below:
T
c
= × 100%
Where:
T
C
= Temperature coefficient
C
TA
= Conductivity at Temperature A
C
TB
= Conductivity at Temperature B
T
A
= Temperature A
T
B
= Temperature B
1.
Press and hold the
o
C
key for 3 seconds to enter the temperature setting.
2.
Press the
or
key to set the temperature to 25
° C.
3.
Place the electrode into the sample solution A and record the temperature value T
A
and conductivity value C
TA
.
4.
Condition the sample solution and electrode to a temperature that is about 5
° C to 10
° C different from T
A
. Record the temperature value T
B
and
conductivity value C
TB
.
5.
Calculate the temperature coefficient according to the formula above.
Addendum 3: How to calculate the TDS conversion factor
To determine the TDS conversion factor use the formula below:
Factor =
Where:
Actual TDS: value from the high purity water and precisely weighed NaCl or KCL reagent.
Actual Conductivity: the meter measured conductivity value.
For example: dissolve 64g of potassium chloride reagent in 1 litre distilled water. If its conductivity value is 100mS/cm, then TDS conversion factor is 0.64.
C
TB
-C
TA
C
TA
(T
B
-25)-C
TB
(T
A
-25)
Actual TDS
Actual Conductivity @ 25
° C
