% RSD in GC

[aniket1706]

Dear All,
Is there any basis on which we keep % RSD limit of "Not more than 15%" in most of the residual solvent content methods??

[rb6banjo]

Am I missing something here? I always thought that calculation of %RSD was only to give you "warm and fuzzy" feeling that your instrument was performing as you expect. RSD's of more than you expect indicate a problem with your equipment. You can set what is "acceptable" wherever you want. If you're tied to some regulatory body, then you have to live with what they say. For residual solvents, if it's 10 ppm or 8.5 ppm or 11.5 and it doesn't matter, then 15% is a good limit. If it matters if it's 13 ppm then an RSD that is 30% is too large. You won't have a good idea that you're instrument is reporting a result that is "accurate enough" for the purpose of the analysis.

[Peter Apps]

Dear All,
Is there any basis on which we keep % RSD limit of "Not more than 15%" in most of the residual solvent content methods??

it's a compromise between cost and how fit for purpose the results are.

Peter