On Tue, 9 May 2006, David Harris wrote:

> Isodat 2.0 for chromatography peak detection/evaluation offers several 
> background correction modes but I can find no explanation as to what they 
> various modes actually do.  Has anyone figured this out? I am particularly 
> interested in understanding the mode ' dynamic BGD' and its parameter 'step 
> width'
> 

The algorithms are presented in

Ricci, P., Merrit, D.A., Freeman, K. H., Hayes, J. M. (1994).
   Acqusition and processing of data for isotope-ratio-monitoring
   mass spectrometry, Org Geochem, 21(6/7), 561-571.

From my experience choosing "Dynamic BGD" does not perform
particularly well and "Individual BGD" can cover virtually
every problem. If your BGD is grossly changing over time and 
if you possibly feel its too high, I'd rather consider 
additional purification of the samples.  


-- 
	Uli Flenker

	Institute of Biochemistry
	German Sport University Cologne
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