Troubleshooting guide

Lab Exercise: Advanced Reporting
Automated Spectral Library Search
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Automated Spectral Library Search
Make certain that Quant.M and Syss.D are still loaded.
Quantification based solely on retention time correlation can lead to erroneous
identification if:
a) Compounds other than the calibrated ones appear in the specified retention
time window.
b) More than one peak elutes in the specified retention time window.
c) The compound is retained on the column longer than the specified window
because of solvent flow rate changes or changing column characteristics.
The ChemStation can automate a library search process to positively identify
chromatographic peaks based upon their UV spectra. In addition, the software
can perform a peak purity check using the settings specified in the Purity Options
dialog box.
1) To set up a library search report, first go to the Report menu and select
Automated Library Search. The Parameters for Automated Identification
panel will appear.
2) The libraries you specify in this window must already exist. You created a
library for this test mix earlier in the course. Select the checkbox for library 1
and click on the Selection box. Load your library.
3) Click on the Edit Search Parms button to the right. Create a search window
of + or - 10%. Set a Threshold of 2 mAU. OK this dialog box.
4) You may perform a purity check. This procedure is recommended before a
library search, since a match is only as reliable as the quality of the separation.
It calculates and reports a purity factor. Purity can be defined by a threshold,
below which questionable results are tagged with an "x" in the report. Select
the Purity check? checkbox.
5) Three search modes can be applied to your application. First, select Identify
by spectral library search.
This mode is the most general search mode. The ChemStation compares the peak
spectra of all those peaks found by the integrator and characterized by their
retention times, with spectra from up to four specified libraries. The name of the
compound with the best match is assigned to the peak. You can specify how good
this match must be with your own threshold value. The ChemStation then refers