Ammonium colorimetric measurements

Ammonium colorimetric measurements

Measuring the concentration of NH₄ in an E. coli/P. aeruginosa growth experiment using Spectroquant kit

Material:

• Ammonium Test Kit (#00683)

A liquid test solution should be performed to achieve a measurement between the ranges of 2-75 mg/L NH₄-N.

Ammonium solution

Prepare solution with 39 mg NH₄-N/L:

• Weigh 220 mg Ammonium Bicarbonate into 100mL volumetric flask (10x concentrated)
• Take 5 mL of the 10x solution in 45 mL water
• Expected final concentration 39 mg N/L

Performing Measurements: Ammonium

Measuring range of the kit: 2-75 mg/L NH₄-N

1. Pipette 5.0 ml of reagent 1 (NH₄-1) into a test tube.
2. Add 0.20 mL of sample when it is among the range of measuring kit (otherwise make proper dilution)
3. Add 1 level spoon of reagent 2 (NH₄-2).
4. Shake vigorously to dissolve.
5. Reaction time: 15 mins
6. Pour sample into the cuvette
7. Select method in the spectrometer by entering the AutoSelector (little black tube)
8. Note the result
9. If the read is above the linear range then put the sample back to the tube test, dilute it and try again.