Re: Smoothing allowance for raw data

Have you tried looking through the EPA's SW-846 methods?  They're online.
Many 'general' areas, too


"Dave White" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Years ago I worked in an environmental lab doing hi-res GC/MS analysis.  I
> vaguely remember a document, I think from the EPA, that specified a limit
to
> the amount of smoothing that could be applied to chromatographic data
prior
> to measuring areas and signal to noise.  This wasn't part of a specific
> method, but some kind of general document that applied to all methods.
>
> Now, ten years later, I'm writing some processing code for another lab
doing
> similar analyses and they have been asking about the smoothing limits.
For
> years, they've always worked with raw, unsmoothed data, but in some cases,
a
> little bit of smoothing may be advantageous.  Obviously, there must be
some
> limit to smoothing, otherwise data could be smoothed to the point that all
> noise disappears.  But, is there an official document that gives smoothing
> reccomendations - "must not reduce peak height/ noise by x%...", "must not
> cause the peak to broaden by more than x%", "no more than x passes with a
> window of y will be allowed...", etc. ?
>
> Any references or pointers would be appreciated,
>
> Thanks in advance,
> --
> Dave White
> SpectraChrom Software
> www.spectrachrom.com
>
>