I need to make a standard curve for quantifying the ammonium produced by Azotobacter in Burk's N-free medium. I already have the OD number data from the Azotobacter and now i need to quantify it. Now i need to know how to make NH4Cl standard solution for the curve? i already have the NaOH solution and Nessler's reagent ready for use. Thanks
I don't understand the problem. NH4Cl is a cheap commercially available material. Just buy it and dissolve it in slightly acidic water.
You prepare one concentration from NH4Cl, add different volumes to your reagent, adjust the solution pH, level the solution up to a constant volume as to get different concentrations from NH4+ in the final volume the record the absorbance of different solution against the concentration.
It's a bit tricky because NH4Cl is hygroscopic, and difficult to weigh out accurately. You can prepare a solution that's about 100 ppm, and quantify the chloride with a AgNO3 (Mohr) titration. Make dilutions from that solution as necessary.
i) The pH of pure ammonium chloride (NH4Cl) aq. sol. can be predicted as I have shown at:
https://www.researchgate.net/post/What-exactly-does-adjusting-8mM-Ammonium-Chloride-to-solutions-of-pH-of-9-and-10-mean/1
ii) The pH of not too concentrate ammonia / ammonium chloride (NH4OH / NH4Cl) aq. sol. can be predicted as I have shown elsewhere at this forum:
https://www.researchgate.net/post/Can-anyone-suggest-a-protocol-to-prepare-a-buffer-of-NH3-NH4Cl-with-pH-10
iii) The pH of not too concentrate pure ammonia (NH4OH) aq. sol. can be predicted as I have shown elsewhere at this forum:
https://www.researchgate.net/post/How_can_i_calculate_PH_of_an_ammunia_solution_without_using_a_PH_meter
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