Salinity Levels Measured by the Conductivity Method

The electrical conductivity of a liquid changes as the nature of the liquids ions increase or change.  Most conductivity meters measure in micro Siemens per cm (µS/cm).  Comparing various bodies of water and their amounts of micro Siemens per cm provides valuable feedback for monitoring, evaluating, and implementing corrective actions as needed.  Did you know that most fresh drinking water will have less than 100µS/cm while seawater has a conductivity of around 5,400µS/cm?

Specifications for the ES-421

  • Catalog#:4210
  • Measurement method:Conductivity
  • Measurement range:0.00 to 10.0% (g/100g)
  • Resolution:0.01% for salt concentration of 0.00 to 2.99%, 0.1% for salt concentration of 3.0 to 10.0%)
  • Measurement accuracy:Displayed value ±0.05%(for salt concentration of 0.00 to 1.0%), Relative precision ±less than 5%(for salt concentration of 1.0 to 10.0%)
  • Temperature compensation: 10 to 40°C
  • Ambient temperature: 10 to 40°C
  • Power supply: 9 volt
  • Dimensions: 17(w)x9(d)x4(h)cm
  • Weight: 300g

The Digital Salt Meter ES-421 measures salinity levels using the conductivity method

There are numerous examples of home experiments where gathering batteries, volt meters, wires, copper electrodes and teaspoons have demonstrated tdescribe the imagehe presence of a higher or lower conductivity (electrical current) in liquid.  To be sure these are fun experiements to try at home or school.  In the working environment however where production and Quality Control are critical there are better tools available.  Digital Salt Meters are designed to delivery accuracy and better resolution of conductivity results in samples quickly.  The ATAGO ES-421 indicates salt % of a sample in digits just by filling up the funnel-shaped sensor section with a small amount of sample (1.0ml approx.) and pressing the Start/Off switch. 

Have you ever wondered how to prepare your sample for testing?

Listen to our Salt Testing Podcast

       
In this podcast we interview a representative from ATAGO and go into detail and discuss some of the issues surrounding salt testing.  Why is it important to test for salt? Which method should we use?  How should we test for salt? Please listen in and let us know if this discussion was helpful.  Also, let us know what other topics you would like us to discuss.
Hank Levi
 

Frequently Asked Questions

  • Q:How is the unit calibrated?
  • A:Press the ZERO button while th sensor is empty and completely clean.  No chemical is necessary.  Perform this zero-setting daily.  When measurement values seem to be off, calibrate the unit with a standard saline soultion.
  • Q:Can tap water be used for sample dilution?
  • A:Always use distilled water whenever possible.  If tap water is used, make sure that the water reads "0" (zero) in advance.
  • Q:Do other electrolytes besides salt affect the readings?
  • A:The amount of other electrolytes found in food is negligible, usually less than 1%.
  • Q:Does the Mohr method and ATAGO salt meters use the same measurement principles?
  • A:The Mohr method, also known as a silver nitrate titration method, utilizes the characteristics of silver nitrate that reacts with chloride ions to measure the salinity %.  The ATAGO salt meters emloy the electric conductivity method.  Both methods measure the salinity but operate on different measurement principles.  However, by creating a conversion table between the two testing methods, correlation between the set of results can be seen.
  • Q:Can the instrument measure the non-sodium total dissolved solids?
  • A:Non-sodium total dissolved solids = Brix-(salinity % x 1.18).  A refractometer with the Brix scale is required.  The salinity % is multiplied by 1.18 to be converted into a Brix value.

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