Quantitation limit

Chromatography Forum: GC Archives: Quantitation limit
Top of pagePrevious messageNext messageBottom of pageLink to this message  By InÍs Pantale„o on Thursday, February 27, 2003 - 06:34 am:

How can I determine experimentally the quantitation limit of my method, i.e., the lowest amount that can be accuratly and precisely determined using the method I developed for my GC?


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Thursday, February 27, 2003 - 12:47 pm:

Prepare standards at various levels and analyze each one in triplicate (or you can use more replicates). Calculate the %RSD of the 3 injections of each concentration of standard. If the % RSD for a certain concentration of standard goes above a certain amount (we use 3 %), you are at the quantitation limit. Actually the lowest level standard that is still below 3% RSD is what we consider to be the quantitation limit. This seems to work pretty well. Hope this helps.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By HW Mueller on Friday, February 28, 2003 - 01:39 am:

Conceptually, it might be easier to use the signal to noise ratio (S/N). S/N of 2-4 are usually considered to be the limit.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Friday, February 28, 2003 - 11:45 am:

We inject a blanco 6 times, calculate noise at the retention time of our peak, and 3.3 times the noise level = LOD, LOQ = 10 x noiselevel


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