Reduction stage data loss...
...associated with the misidentification of chromatographic
peaks.
The chromatogram processing software utilizes several user-defined parameters
that, in effect, tell the software what peaks it is looking for and approximately
where (i.e. at what retention times) it should find them. When a detected peak
falls within a predefined time window, the software identifies the peak according
to the specifications it finds for that time window and writes the processed
data values into their appropriate locations within the database. During batch-mode
processing, chromatograms are examined in chronological order and the predefined
time windows are continuously updated with the retentions times of the peaks
isolated from the current chromatogram. These recentered time windows are then
saved and compared against the next chromatogram. In this way the software
will not fail to identify a peak whose retention time has slowly drifted out
of its initial identification window over the course of several hours. The slow
drift of retention times is normally not a problem. However, if in the course
of batch-mode processing, a peak suddenly jumps for any reason -- and there
are many reasons -- the software can either mistake another peak (i.e. the wrong
peak) for the one it is looking for and begin inserting the wrong values into
the database, or it may lose track of the peak altogether and begin inserting
the "missing peak" flag in the database.
|
Disclaimer
Privacy Notice
|
Climate Monitoring & Diagnostics Laboratory
Halocarbons & other Atmospheric Trace Species
325 Broadway R/CMDL1
Boulder, CO 80305
|
|
