Using the S/N method to determine LOD and LOQ for an HPLC analysis, would the experiment look something like this?
- Prepare standard solutions at varying, yet very low concentration.
- Inject them as per the method.
- Calculate S/N for each.
- Finally, determine which concentration of solution exhibits a S/N ~ 3:1 and this becomes the detection limit (LOD). Likewise the solution with S/N ~ 10:1 becomes the limit of quantitation (LOQ).
I would also apply a requirement of RSD NMT 20% for all injections at the LOQ.
Do you agree with this basic LOD/LOQ experiment?
Any advice would be helpful as I am reviewing a contractor’s work which doesn’t seem to make sense to me.