Absence of compound

[chandresh.soni]

Hi everyone
I want to know in which case we can say that a compound is absent in another compounds (as in one method or technique it may absent but on another method or technique it may present on ppm level or there are so many techniques present which can trace up to fentogram level.

[Peter Apps]

You can never show that a compound is absent. All you can do it to report it as not detected, with a statement of the lower limit of detection of the method.

Peter

[skunked_once]

To quote someone else "Absence of evidence is not evidence of absence".

[Consumer Products Guy]

Read and re-read the above two posts. We frequently get asked similar.