Page 121 - Chiral Separation Techniques

98 4 CHIRBASE: Database Current Status and Derived Research Applications using …

also the secondary and the gray literature: manufacturer catalogues, posters or lec-
tures from congresses and unpublished experiments sent by the authors.
Some details of the database are available on the Web [6] and consist today of
about 61 000 different chiral separations (Table 4-1). Between 12 000 and 15 000
new separations are stored continuously each year in CHIRBASE.

Table 4-1. Overall statistics.
Number of entries (unique sample-CSP combinations) 40 000
Number of experiments (different chiral separations) 61 000
Number of samples with 2D coordinates 18 000
Number of samples successfully converted into 3D coordinates 16 277
Number of CSPs (2D co-ordinates) 1077
Number of solvents or modifiers (2D co-ordinates) 205
Number of entries with data corrected/completed by the authors 6110
Number of new chiral separations per update (each 4 months) 3–5000

As already stated above, the database has been developed using ISIS software.
The program operation is very simple, and about 30 min to learn the particular com-
mands of this structure-searching program. ISIS provides both storage and retrieval
of chemical structures. It is also possible to store text and numeric data into database
entries. Because molecular structures are searchable in many ways, ISIS software is
an excellent tool for exploiting data, and not simply archiving it.
ISIS databases are hierarchical, so CHIRBASE was designed to incorporate about
60 data fields on several levels of detail (the main fields are listed in Table 4-2). The
first level contains the molecular structure of the sample combined to the molecular
structure of the CSP, producing a unique location or entry for a specific sample-CSP
couple. Consequently, in the current version of CHIRBASE, which contains 40 000
entries, one entry corresponds to the separation of one sample on one CSP and con-
tains in different sublevels a compilation of all the references and the various ana-
lytical conditions available for this separation.
If some fields may be empty in the sublevels, all the fields in the main level are
required for each entry. A new chiral separation record can be added in CHIRBASE
solely if the authors correctly identify both sample and CSP. Since the beginning of
the project, our policy has been to contact the authors of all publications containing
incomplete, ambiguous or inconsistent data and to ask for additional information.
Providing the separations with unique case numbers helps us considerably in this
essential task, and also facilitates avoiding redundancies in the database. When chi-
ral separations are reported for the second time in a new publication with exactly the
same chromatographic conditions, this is stated in a footnote added in the field
« comments ». In this field, miscellaneous information that cannot appear elsewhere
are listed (detection limit, description of a reported chromatogram, racemization
study, mobile phase limitations, etc.).