Method validation for Qualitative analysis by GC-MS

[Mia]

Good day

I have to look for impurities in technical material. Normally I inject a analytical standard (approx. 1000 ng/ul) in full scan mode, together with a solvent blank and the technical material. For ISO 17025 it is a requirement to do method validation. How will you do method validation for this and is there any way that I can take part in proficiency tests?

[tangaloomaflyer]

I would contact your national accreditation agency for advice.

[Don_Hilton]

I have seen reference to an ISO procedure for abilty to detect and identify unknowns. It involves multiple injectios of a mixture with compunds present at low levels. You can determin the hit rate for detection and correct identification of the compunds at various concentrations. I don't remember the details, but will try to find the reference when I get in to work today...

[tangaloomaflyer]

That would be interesting. I run an unaccredited qualitative method that is seriously in need of some evaluating criteria. We use an arbitrary minimum spectral match percentage, but some of the less experienced chemists tend to take the library hits as gospel without cosidering what is actually possible to differentiate by mass spec.