Ammonia Determination (Nesslerization spectrophotometric method)
Protocol objective.
Determinate Ammonia concentration from liquid environmental samples.
Adapted from: www.irsa.cnr.it/Docs/Capitoli/4030.pdf
Duration: 2 h
Materials
- Cuvette (1 mL)
- Falcon Tube 50 mL, and 15 mL
Equipment
- Spectrophotometer UV-VIS
- Chemical hood
- Pipette 1000 µL and 100 µL
Solutions
- Nessler reagent (TOXIC)
- Rochelle salt solution: the potassium sodium tartrate solution (1.8M)
Procedure
- Preparation of Rochelle salt solution: Add 50 g of Potassium Sodium Tartrate to 30 mL of deionized water and boil to remove ammonia trace. Once the solution is cold again, add deionized water until 100 mL.
- Prepare the BLANK, adding 1 mL of deionized water in one couvette.
- Put 1 mL of each environmental sample in the respective couvette.
- Add to each couvette, 100 µL of Rochelle salt solution, 100 µL Nessler Reagent (DO IT UNDER THE CHEMICAL HOOD), cover all the couvett with silver paper for 15 min (dark incubation).
- Set the spectrophotometer to 420 nm and use the BLANK sample to set at zero the instrument.
- Measure all the samples and note the OD measured.
- Transfer all the data obtained in the Wetbench_Geochem_Calc.ods file in the respective column.
Expected results (quantitative information, graphics, images)
| mg/L | OD |
|---|---|
| x | y |
Common problems, troubleshooting and solutions
- A distinct protocol is in progress to detect and correct potential interferents within the samples
Calculations
Use the equation of the standard curve to calculate the concentration x, equivalent to the concentration of Ammonia in your sample.
Equation 1. y = (0.21*x) - 0.00326
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