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Chromium

Saurabh Levin edited this page Dec 27, 2018 · 5 revisions

Things You Will Need

  1. 1 Dropper of Chromium Reagent A

  2. 1 vial of Chromium Reagent B

  3. A smartphone with the ffem Collect and ffem Water apps installed, and an alignment sticker around the camera

  4. A Cuvette and pipe

  5. A 10 ml measuring tube

  6. Tissue Paper

  7. A sample of water to test


Steps

  1. Open the ffem Collect app, and select "Fill Blank Form". Select the form you need to fill out.
                    
  1. Answer all the questions in the form, swiping left to go to the next questions. When you reach the water quality questions, launch the test for Chromium
                    
  1. Rinse the empty cuvette and measuring tube twice with the sample to remove any traces of previous solutions.


  1. Measure 10 ml of the sample with the measuring tube.
  1. Open the dropper of Chromium reagent A and add 5 drops to the measured sample. Close the lid of the measuring tube and shake it to ensure proper mixing of the reagent and sample.
                
  1. Open the vial of Chromium reagent B, and add it to the solution. Close the lid of the measuring tube and shake it to ensure proper mixing of the reagent and sample.
                
  1. Pour the contents of the mixing tube into the provided cuvette. Close the lid and fit the cuvette into the pipe.

                                        

  1. Launch the test on the app selecting "No Dilution" on the next screen.
                    
  1. Place the phone face down, and use the sticker to help center the cuvette over the camera. Wait for 10 minutes for the test to complete - you will hear 6 beeps and a "Test Completion" sound.
                                        
  1. You should receive a contaminant concentration value in ppm. Tap Accept Result to return to the survey.
                   
  1. Empty the contents of the cuvette and rinse it once.
  1. Complete the rest of the survey, and submit it once you have filled in all the forms.

Reagent details

  1. 2, 5 Diphenyl carbazide : Weigh 0.250 gm of 2, 5 diphenyl carbazide in 50 ml of acetone
  2. 0.02 N Sulphuric acid :

Calibration

Prepare calibration standards 0.0, 0.1, 0.5, 1.0, 2.0, 5.0 mg/L by diluting stock solution of chromium (100 ppm) with distilled water. Take 10 ml standards in a 15 ml centrifuge tube and add 5 drops of 0.02 N sulphuric acid and 0.2 ml of 1,2 diphenyl carbazide reagent. Open ffem water app and calibrate all calibration points.

Testing a water sample Take 10 ml water sample in 15 ml centrifuge tube and add 5 drops of 0.02 N sulphuric acid and 0.2 ml of 1,2 diphenyl carbazide reagent. Wait for 5 minutes for colour development Open ffem water app and run the test to get a result.

Validation Testing

Sr.No. Standard (ppm) Reading by FFEM
1 0 0.02
2 0.1 0.12
3 0.5 0.86
4 1 1.02
5 2 1.96
6 3 2.97
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