Principle

Potassium is a colorimeteric test.

The Indian Standard for drinking water does not specify an acceptable limit of potassium in water. However, according to the WHO, drinking water should have a potassium level below 12 mg/l.

Calibration

To prepare calibration standards, take 5 ml of distilled water. Depending on if you chose minimal or full calibration, prepare standards as below.

Full Calibration

Standard Drops
0 mg/l 0
10 mg/l 10
20 mg/l 20
30 mg/l 30

Minimal Calibration

Standard Drops
0 mg/l 0
10 mg/l 10
30 mg/l 30

Take 5 ml of the 0 mg/l Potassium standard, dilute it to 10 ml with distilled water. Add 5 drops of Reagent A and mix well. Add 10 drops of Reagent B and mix well.

  • Take the resulting coloured solution and fill it into the white cuvette provided.
  • Place the cuvette under the light box and turn it on.
  • Place the phone over the stand.
  • Go to Settings > Colorimetric Test > Calibrate and choose Potassium.
  • Select the calibration point, 0 mg/l in this case.
  • Click on Start Camera.
  • Position the cuvette so that the middle, most uniformly lit portion is within the circle.
  • Select Analyze.
  • You should have your first calibration point. Repeat similarly with the other calibration points.

Test

This test uses the Potassium reagents.

  • Collect 5 ml of sample water, add 5 drops of Reagent A and 10 drops of Reagent B and shake for 5 seconds to mix well. Place the solution in the white cuvette.
  • Place the cuvette under the lightbox and turn it on.
  • Place the phone over the stand.
  • From the home screen choose Colorimetric Test > Water > Potassium.
  • Choose No Dilution if this is the first test, you might have to dilute the sample and retry later if you get an error.
  • Click on Start Camera.
  • Position the cuvette so that the middle, most uniformly lit portion is within the circle.
  • Select Analyze.
  • After some time, the app will display a result.