The first button to the right of the “Search History” list box is used to clear the search history (Clear History
button). The next button (the Replicates On/Off button) to the right is used to toggle the listing of replicate
spectra on and off when the mainlib Library of the NIST/EPA/NIH Library is searched.
The button to the right of the Replicates button is
used to display only hits with the highest Match
Factor when more than one hit has the same CAS rn.
This is the Best matching only button. This feature
is especially useful when more than one library is
being searched, and some of the spectra in these
libraries have same CAS rn’s associated with them.
The button to the right of the Best matching only
button is the View hit list search options button.
Selecting View hit list search options button will
result in the display of a dialog box that lists the
parameters of the currently displayed search
including library search, constraints, limits, and type
of search (Figure 10).
The last button on the right, the View substructure
information button, displays the Substructure
Information dialog box. The Substructure
Information dialog box contains a list of the
probability of the presence and absence of
substructures that may be associated with a
compound that produced the searched mass
spectrum along with additional predictions about this
compound’s molecular weight and estimate of the
numbers or atoms of chlorine and/or bromine that
may be contained. This is especially useful with
either a Neutral Loss or a Hybrid Neutral Loss
“Similarity” search.
Figure 10. List of options used for the
currently displayed search results.
Title Bar, Tool Bar, and Status
Bar
At the top of the display of each of the NIST MS Search Program’s tab is a Title Bar. The contents of a title bar of
the active tab is also displayed in the Title Bar of the Program window. When the Lib. Search or Other Search tab
is displayed, this Title Bar will contain information about the currently displayed search. In the case of a User
spectrum search, this will include the search type used, whether or not constraints were used, and if any type of
limits were applied to the search. In the case of the Other Search tab, the Title Bar will contain the type of
search that was done (i.e., Formula, Molecular weight, Any peaks, etc.) and whether or not constraints were
used. When the Compare tab is displayed, the Title Bar contains the number of spectra available for comparison
regardless of the number displayed.
At the bottom of Program’s display, below the Program’s tabs, is the optionally displayed Status Bar. The Status
Bar’s display can be turned off by selecting or deselecting Status Bar from the View menu. When a User
Spectrum search is being conducted, the left side of the Status Bar will have displayed “Comparing XXX Library
spectra with submitted spectrum” where XXX is the number of spectra that were found during the presearch (see
Search Algorithms in Appendix 5). If “Off” has been selected in the Presearch area of the Search tab of the
Library Search Options dialog box, XXX will represent the total number of spectra in the library(ies) being
searched.
There are five fields on the right side of the Status Bar. The left-most of these five fields will have displayed the
selected search type in the “Spectrum Search Type” area of the Search tab of the Library Search Options dialog
box (Neutral Loss, Hybrid, or Simple if the “Similarity” search is selected; and Quick or Ident depending on
whether a Quick or Normal “Identity” search has been selected).
The next four fields to the right of the box indicating the selected search type pertain to the currently displayed
search results. The first box to the right contains the type of search that was used in the displayed search results.
The next box to the right will have contained “Rev” if the Hit List is sorted according to the Reverse Match value
(the Match Factor obtained by ignoring all peaks that are in the sample spectrum but not the library spectrum). To
set this mode select Reverse Search check box in the Spectrum Search Options section of the Search tab of the
Library Search Options dialog box. The third box will contain the number used as a precursor MW value in a
Page 14 NIST 08 MS Library and MS Search Program v.2.0f