SEARCHING CHEMICAL ABSTRACTS (PAPER VERSION)

See also: Chem Abstracts Handout Fall 2006

Chemical Abstracts Service (CAS), a division of the American Chemical Society, surveys chemical literature published worldwide. Materials covered include articles, patents, books, dissertations, audio-visual materials, government reports and conference proceedings. CAS provides informative abstracts and controlled vocabulary indexing for these materials.

Chemical Abstracts is published in two numbered volumes a year. Each volume consists of abstracts, or summaries, numbered sequentially and arranged in 80 subject groupings. In order to find relevant abstracts, several indexes are also published for each volume and index guides are published periodically. How you approach finding abstracts is different depending on what information you have.

BEGINNING THE SEARCH FOR INFORMATION ON A SUBJECT OR CHEMICAL SUBSTANCE:  Using the Index Guide

The first step to finding information on a subject or a particular chemical is to decide what time period you would like to search. Choose a volume number and find the Index Guide that covers that volume. The Index Guide is a cross reference that alphabetically lists subject terms, synonyms, acronyms and tradenames or trivial names and refers you to the CAS preferred term.

If you are looking up a general subject, verify that it is used or see other headings suggested. Read any notes to see if other subjects may also be relevant.

Examples:

Therefore, looking up Condensation reaction, Perkin-Fittig; starvation; hunger; and Microorganism nutrition, starvation in the General Subject Index will lead to abstracts of articles about these subjects if there have been any written during this time period; looking up Perkin-Fittig reaction in the General Subject Index will not work since this term is not used by CAS.

If you are looking up a chemical, note the suggested name, together with the registry number in brackets following the name as a way of checking that you look up the correct substance. Registry numbers are assigned by CAS and uniquely identify a particular chemical substance, regardless of what other nomenclature may be used to describe it. Use the Chemical Substances Index to find abstracts of articles written during this time period about this chemical.

Example:

Go next to the appropriate index and look up (2H-1,4-)Benzodiazepin...... Older indexes may differ slightly from those described here.

Using the Indexes

GENERAL SUBJECT INDEX (SINCE 1972)

CAS-preferred subject terms are listed here in alphabetical order followed by subheadings. Brief descriptions of the item(s) abstracted that deal with this subject will be listed, followed by their abstract number.

Example:

CHEMICAL SUBSTANCE INDEX (SINCE 1972)

CAS-preferred chemical substance names as found in the Index Guide are listed here. Index names are listed alphabetically by "parent" compound, usually the name of a structural skeleton plus a suffix denoting the principal functional group (2H-1,4-Benzodiazepin-2-one in the example above), with the rest of the name including any substituent groups, modifications and stereochemical information indented following each parent. Sometimes a common name for the substance will follow in italics. Because terms can get quite lengthy, always try to check the registry number given in brackets following the chemical substance name to ensure that you have found the correct substance. It may also be useful to note the volume number and page number where you found the information, as it would be easier to find again this way if you need to check something. Detailed rules for alphabetizing etc. can be found in the front of the index. Brief descriptions of the item(s) abstracted that deal with this subject will be listed, followed by their abstract number.

Example:

INFORMATION TO NOTE FROM INDEX:

If you are searching in a collective index, for example the Tenth Collective Index which covers abstracts from v.86-v.95, the number before the colon refers to the volume the abstract is in, the number after the colon is the abstract number: i.e., 92:133271k. If it is a one volume index just the abstract number is given: i.e., 133271k or 170257y. Because abstract numbers repeat in each volume, it is essential to make sure you look up the abstract IN THE CORRECT VOLUME.

Abstracts of books will be preceded by a B, abstracts of patents by a P, abstracts of review articles by an R. If you are looking only for primary research articles, do not choose to look up these abstracts. The small letters following the abstract number are not relevant to description of the abstract. To see the entire abstract, go to that number IN THE CORRECT VOLUME.

Using the Abstracts

INFORMATION TO NOTE FROM ABSTRACT:

The abstract number and the title are printed in bold type. Authors’ names are listed, with the location of the work following in parentheses. The journal title is abbreviated and in italic type, followed by the year of publication, volume and issue number, inclusive pages and the language of the work abbreviated in parentheses. A descriptive abstract follows.

Example:

Be sure to note the language, as this may influence whether you wish to pursue looking up the information. CSUF does not collect foreign-language periodicals extensively. Patent and book abstracts will have slightly different formats.

LOCATING AN ORIGINAL JOURNAL ARTICLE:

Since journal names are abbreviated you will need to find the full name to determine where to find the journal. The Chemical Abstracts Service Source Index (CASSI) lists journals abstracted by the service alphabetically by short journal title. Another source is Periodical Title Abbreviations.

Check the library catalog (OPAC) by doing a title search on the journal title (in the sample above: Antimicrobial Agents and Chemotherapy.) A journal will have the location PERI for periodical.

Example:

Here it is clear that choice 2 is the correct one, and the call number where the journal is located on the 2d floor of the library is given, but for more complete information on which volumes and dates the library owns, type the number in front of the line you wish to see, in this case 2:

Note the call number (QR 1 A3) and the holdings information (LIB. HAS) to determine if the particular volume and issue you need will be present. Journals are kept on the 2d floor of the Pollak Library, North Wing in call number order. They do not check out.

If the material you want is not available in the library you may request it by interlibrary loan (forms are available at the Reference Desk or at InterLibrary Loan; typically it may take 5-10 working days to receive notice that the requested materials have been received) or search other library catalogs to find out if you can go somewhere else to view the material.

Formula Index: allows you to look up molecular formulas to find relevant chemical substance names and associated abstract numbers. The molecular formula is given in Hill order: C (if present), H, other elements in alphabetical order, e.g., C14H24N2O7. Formulas are arranged in ascending numerical order,

Author Index: lists authors alphabetically by last name, then by first and middle initial (even though full names may be given). First (or primary) authors have abstract numbers and brief descriptions, other authors will be cross-referenced to the first author.

Patent index (since 1981): lists abstract numbers of original patents by country and number, and gives cross-references to these abstract numbers from equivalent patents.

Index of Ring Systems: orders substances by the number of rings, their size and elemental composition. Names of chemical substances sharing this ring system will be listed.

A separate work, the Registry Handbook, lists CAS-assigned registry numbers in order numerically, followed by the preferred chemical substances name and molecular formula to look up in these indexes to find relevant abstracts.

FOR MORE INFORMATION:

In each volume (or multivolume collection) of Chemical Abstracts, the first volume of each particular index will have a detailed explanation of coverage and directions for use. Examples of how terms are ordered will be given, as well as keys for interpreting the information found.

The Index guides have information on the rules and procedures for deriving index names.

CAS has produced a short pamphlet, How to search print CA, that is kept at the Reference Desk. There is also a useful book by Barbara Allan and Brian Livesey, How to use Biological abstracts, Chemical abstracts, and Index chemicus, located  in the Reference section. The history of CAS and the transition from the printed products to the online versions is documented by Hedda Schulz in From CA to CAS online.

Notice that there are several steps to obtaining relevant articles using Chemical Abstracts:

1) Use Index Guide for correct terminology
2) Use index (chemical substance, general subject or other) to find relevant abstracts
3) Look up abstract(s)
4) Find full journal title using CASSI or Periodical Title Abbreviations
5) Use OPAC to determine if library has title and issue
6) Find article on 2d floor or request by interlibrary loan

Prepared by Elizabeth Housewright, with subject-specific input from Sung Sam Kim (Spring 2001)
Updated and maintained by Barbie McConnell (2004-present)
An administrative page of the Paulina June & George Pollak Library at California State University, Fullerton.
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Last Updated: 11/28/07.