Principle

Nitrate is a colorimeteric test. This test uses 2 reagents per test that are shipped in small packets.

The Indian Standard for drinking water holds that the acceptable limit is 45 mg/l with no relaxation.

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 2
25 mg/l 5
50 mg/l 10
75 mg/l 15

Minimal Calibration

Standard Drops
0 mg/l 0
50 mg/l 10
75 mg/l 15

Take 5 ml of the 0 mg/l Nitrate standard, and add the contents of Reagent A and Reagent B. Shake till dissolved.

  • 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 Nitrate.
  • 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.
  • This test takes 6 minutes (360 seconds) to develop ideal colour. Click on Start Timer to start a timer, or you can Skip Delay if you have already waited 5 minutes.
  • You should have your first calibration point. Repeat similarly with the other calibration points.

Test

This test uses the Nitrate reagents.

  • Collect 5 ml of sample water, add the contents of Reagent A and Reagent B and place in the white cuvette.
  • Place the cuvette under the light box and turn it on.
  • Place the phone over the stand.
  • From the home screen choose Colorimetric Test > Water > Nitrate.
  • 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.
  • This test takes 6 minutes (360 seconds) to develop ideal colour. Click on Start Timer to start a timer, or you can Skip Delay if you have already waited 5 minutes.
  • After some time, the app will display a result.