Bante Instruments A Series, User Manual

Page: 33 / 46

A150/151 I 32
Appendix
Preparation of Conductivity Standard Solutions
1. Place the analytical grade potassium chloride (KCl) in a beaker
and dry in an oven for about 3 hours at 105° C (221° F), then cool
to room temperature.
2. Add the reagent to a 1 liter volumetric flask according to the
instructions in table below.
3. Fill the distilled water to the mark, mix the solution until the
reagent is completely dissolved.
Conductivity Standard Reagent Weight
84 µ S/cm KCl 42.35 mg
1413 µ S/cm KCl 745.5 mg
12.88 mS/cm KCl 7.45 g
111.8 mS/cm KCl 74.5 g
Calculating the Temperature Coefficient
1. Do not connect the temperature probe to the meter.
2. Press and hold the
° C key to enter the temperature setting.
3. Press the

/

key to set the temperature to 25° C and press
the Enter key to confirm.
4. Place the conductivity electrode into the sample solution, record
the temperature value T
A
and conductivity value C
TA
.
5. Condition the sample solution and electrode to a temperature T
B
that is about 5 to 10° C different from T
A
. Record the conductivity
value C
TB
.
6. Calculate the temperature coefficient using the formula below.
T
C
= [C
TB
– C
TA
] / [C
TA
(T
B
– 25) – C
TB
(T
A
– 25)]
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
Calculating the Cell Constant
1. Reset the meter.
2. Place the electrode into a standard solution and record the
reading.
3. Calculate the cell constant using the following formula.
K = (C
std
/ C
meas
) × G
Where:
K = Cell constant
C
std
= Value of conductivity standard solution
C
meas
= Measured value
G = Raw cell constant (0.1, 1 or 10)
Calculating the TDS Conversion Factor
To determine the TDS factor of sample solution use the formula below.
Factor = Actual TDS / Actual Conductivity @25° C
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 64 grams of the potassium chloride (KCl) reagent in 1 liter
distilled water. If measured conductivity is 100 mS/cm, then TDS factor
is 0.64.
Conductivity to TDS Conversion Factors
Conductivity at 25° C
TDS (KCl) TDS (NaCl)
ppm Factor ppm Factor
84 µ S/cm 40.38 0.5048 38.04 0.4755
1413 µ S/cm 744.7 0.527 702.1 0.4969
12.88 mS/cm 7447 0.5782 7230 0.5613
Optional Accessories
Conductivity Electrodes
Order Code
Description
CON-0.1 For measuring the pure water
CON-1 For general purpose applications
CON-10 For measuring the high conductivity liquids
Temperature Probe
Order Code
Description
TP-10K 3.5 mm jack plug, 1 m (3.3 ft) cable
Solutions
Order Code
Description
ECCS-84 Conductivity standard solution 84 µ S/cm, 480 ml
ECCS-1413 Conductivity standard solution 1413 µ S/cm, 480 ml
ECCS-1288 Conductivity standard solution 12.88 mS/cm, 480 ml
ECCS-1118 Conductivity standard solution 111.8 mS/cm, 480 ml
Communication and Power Supply
Order Code
Description
USB-2303B USB connector A to B, 1 m (3.3 ft) cable
DCPA-12V 12V DC power adapter, european standard plug