Upon collection of a freshwater sample, does it need to be immediately frozen for ammonia analysis at a later date or can it be left at ambient temperature for up to 24 hours before it is frozen? I'm aware that bacteria can alter water parameters over time but I don't know whether it would have a significant affect if the sample if frozen within 24 hours.
Any help would be appreciated - thank you in advance!
We do freeze them just right after sample collections and samples are brought to room temperature prior to analysis. This method gives couple of months stability for NH4 samples. If you plan to analyze them in couple of days, you can keep them unfreeze.
Thanks for your answer! Do you think that upon sample collection they could be kept at room temperature for 24 hours then freeze them? Or would the NH4 concentration significantly change in 24 hours?
Keep the sample in room temperature and dark place. for detail please ref: Jeong 2013
for ammonia in water, spectroscope photo metric indo phenol blue color method is good option.
Megan..... Ammonia forms hydrogen bonding with water molecules and this will increase the strength of the solution. However, freezing the sample will help the stability of the solution, The concentration level will be kept representative of the originally samples water.
I have had a sediment samples storage for 10 months at -80°C. I would like to know if the concentration of ammonium could have changed along this months?
If analysts be made within 24 hrs and sample collected in stilized glass container, not necessary to keep frozen, in particular for biological analysis.
Sample collection For ammonia analysis and to get accurate results, it is recommended analyse earliest . However Frozen sample may cause errorsome result .
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