10
2. Standard solution of 12.90 mS/cm at 25 °C : Accurately
weight out 7.4365 grams of research grade dried Potassium
Chloride (KCL). Dissolve in 1000 ml of distilled water.
3. Standard solution of 111.9 mS/cm at 25 °C : Accurately
weight out 74.264 grams of research grade dried Potassium
Chloride (KCL). Dissolve in 1000 ml of distilled water.
[Note:
You can store the unused portion of the standard
solution in a plastic container for six months but the air space
between the cap and the solution must be kept to an absolute
minimum. Storing the excess solution below 4 °C can
increase the storage life. If you have any doubt of the
accuracy of the stored solution, a fresh batch should be
prepared.
]
