PASCO PS-2172 Advanced Chemistry Sensor - Manual (Page 6)

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Advanced Chemistry Sensor Conductivity
6
store. The table (right) lists typical conductivity values for common aqueous solutions
at 25 °C.
As a rule of thumb, to estimate total dissolved solids (TDS) in parts per million
(ppm), divide the conductivity in
S/cm by 2:
Conductivity Calibration
The conductivity measurement can be calibrated; however, for most applications cali-
bration is not necessary. Use a one-point calibration with a standard solution of
known conductivity. For instructions on preparing a standard solution, see the Appen-
dix section. Refer to the SPARKvue/SPARK SLS, Capstone, or Xplorer GLX User’s
Guide for calibration instructions.
Conductivity Electrode Maintenance And Storage
To ensure accurate and reproducible results, the electrode must be clean. Substances
on the electrode may contaminate the solution being tested and change the conductiv-
ity. To clean the electrode, dip the end into a detergent solution or dilute nitric acid
(1%) and stir for three minutes, then rinse with deionized water.
For storage, dry the electrode and return it to its box. Before use, soak the electrode in
distilled water for at least 5 minutes.
Solution Conductivity
(
S/cm)
Ultra-
pure
Water 0.05 to 0.75
Drinking
Water 50 to 1500
Ocean
Water ~53000
TDS (ppm)
Conductivity S/cm  
2
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