9.3. Step 3 – Uncertainty sources

All possible uncertainty sources have to be considered and those that are likely to be influential have to be taken into account.

Uncertainty sources: in general 
http://www.uttv.ee/naita?id=17638

https://www.youtube.com/watch?v=EWYNWtRgvmI

Uncertainty sources: one by one
http://www.uttv.ee/naita?id=17639

https://www.youtube.com/watch?v=kEfhKCj44N0

The following schemes list the main uncertainty sources in chemical analysis and comment on the presence or absence of the respective uncertainty sources in our case. [1]Comment on the memory effect as uncertainty source: Memory effect is problematic first of all in the case of trace analysis and secondly, if the analyte is specifically prone to adsorption on glass or plastic surfaces. In this case, although the concentration of ammonium in the sample is quite low, it is still not yet a true trace analysis. Ammonium ion is by no means a strongly adsorbing species. Therefore we can leave the memory effect as uncertainty source out of consideration. 

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[1] Comment on the memory effect as uncertainty source: Memory effect is problematic first of all in the case of trace analysis and secondly, if the analyte is specifically prone to adsorption on glass or plastic surfaces. In this case, although the concentration of ammonium in the sample is quite low, it is still not yet a true trace analysis. Ammonium ion is by no means a strongly adsorbing species. Therefore we can leave the memory effect as uncertainty source out of consideration.