ASTM E204-98(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: E 204 – 98 (Reapproved 2002)
Standard Practices for
Identification of Material by Infrared Absorption
Spectroscopy, Using the ASTM Coded Band and Chemical
Classification Index
This standard is issued under the fixed designation E204; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope E932 Practice for Describing and Measuring Performance
of Dispersive Infrared Spectrometers
1.1 These practices describe a data system generated from
E1252 Practice for General Techniques for Qualitative
1955 through 1974. It is in world-wide use as the largest
Infrared Analysis
publicly available data base. It is recognized that it does not
represent the optimum way to generate a new data base with
3. Summary of Practices
the most modern computerized equipment.
3.1 Arepresentativesampleofthematerialtobeanalyzedis
1.2 Thesepracticesdescribeproceduresforidentificationof
separated into its individual components, if required, and each
individual chemical substances using infrared absorption spec-
component is introduced into a suitable sample cell or matrix,
troscopy and band indexes of spectral data. Use of absorption
mainly according to its physical state. The spectrum is re-
spectroscopy for qualitative analysis has been described by
2 corded over a characterizing range. The choice of spectral
many (1-8), but the rapid matching of the spectrogram of a
range and instrument is dictated by a general consideration of
sample with a spectral data in the literature by use of a band
the chemical nature of the sample (3-5).Anote is made of the
index system designed for machine sorting was contributed by
spectral positions of prominent absorption bands and, option-
Kuentzel(9).ItisonKuentzel’ssystemthattheASTMindexes
ally,ofknownchemicalandphysicalpropertiesofthematerial.
of absorption spectral data are based.
Thequalitativechemicalcompositionofthematerialmaythen
1.3 Use of these practices requires, in addition to a record-
be identified by searching the coded data file for compounds
ingspectrometerandaccesstopublishedreferencespectra,the
having matching characteristics. Details on searching proce-
encoded data and suitable data handling equipment.
dures are available elsewhere. Details of the code are in the
1.4 This standard does not purport to address all of the
following sections.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Apparatus
priate safety and health practices and determine the applica-
4.1 Infrared Spectrophotometer—Aspectrophotometerwith
bility of regulatory limitations prior to use.
capabilities equivalent to an instrument with a rock salt prism
operated under parameters compatible withAnalytical Spectra
2. Referenced Documents
(8, 10) and with wavelength accuracy to 0.05 µm by compari-
2.1 ASTM Standards:
son with the indene spectrum in Practice E932.
E168 Practices for General Techniques of Infrared Quanti-
4 4.2 Laboratory procedures for obtaining spectra are de-
tative Analysis
scribed in Refs (3-5) and in Practices E168, and E1252.
4.3 Data-Handling Equipment—It is possible to convert
1 data on the ASTM magnetic tape to IBM cards, and to use
These practices are under the jurisdiction of ASTM Committee E-13 on
Molecular Spectroscopy and are the direct responsibility of Subcommittee E13.03 sorters or collators to manipulate the data. However, the file is
on Infrared Spectroscopy.
large and it is more efficient, and with good software, more
Current edition approved Dec. 10, 1998. Published August 1999. Originally
effective, to use computers. These may be either dedicated or
published as E204–62T. Discontinued 1998. Reinstated December 1998.
time-shared. Thus, the minimum equipment requirement is a
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
these practices.
The ASTM Infrared Spectral Index, AMD 33 and its supplements may be
purchased in the form of magnetic tapes, from Sadtler Research Labs., Inc., 3316 Publicly available systems are as follows: IRGO, Chemir Labs., 761 W.
Spring Garden St., Philadelphia, PA 19104. Kirkham, St. Louis, MO 63122; SPIR (Canada only), National Research Council,
Annual Book of ASTM Standards, Vol 03.06.
100 Sussex Dr., Ottawa, Ontario, Canada K1A OR6.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E 204 – 98 (2002)
TABLE 1 Catalogs of Spectrograms Covered by ASTM Punched
computer, a program, and the coded data (and either batch
Cards Indexing Infrared Absorption Data
processing facilities) or a teletypewriter or terminal with
A
A API Research Project 44
modem for accessing these resources for interactive searches.
B
B User’s own file of spectrograms
C
C Sadtler catalog of spectrograms
5. Index
D
D NRC-NBS file of spectrograms
E Literature
5.1 The index data on approximately 145 000 spectra are
E
F Documentation of Molecular Spectroscopy
availableonmagnetictape.Themainabsorptionbandsofeach
F
G Coblentz Society Spectrograms
G
spectrum are coded to the nearest 0.1 µm.
H Chemical Manufacturer’s Association (CMA)
H
J Infrared Data Committee of Japan
5.2 In addition to the code for spectral data of chemical
I
K Aldrich Library of Infrared Spectra , 1970 Edition
substances, there are codes for chemical-structure classifica-
A
American Petroleum Institute, Research Project 44, Infrared and Ultraviolet
tion, empirical formula, melting or boiling point, and serial
Spectral Data, Texas Agricultural and Mechanical College, College Station, TX,
number reference. Other codes include data on sample state,
1943 to date. Loose-leaf.
B
wavelengthintervalsofstrongestbands,andno-dataareas.For Users are encouraged to submit spectrograms (or the pure compound in some
cases) to one of the other organizations listed. It is unlikely that any individual
agivensubstance,thecodedspectraldataarealmostinvariably
laboratory can code its spectral data and punch cards at the cost of the ASTM
unique as is the pattern for coded chemical structure and
cards (about one cent each).
C
Standard and Commercial Spectra, Sadtler Research Laboratories, 3316
physical properties. Variables may be searched in any desired
Spring Garden St., Philadelphia, Pa. 19104. Loose-leaf. The Sadtler organization
combination to locate a standard spectrum similar to that of a
also offers a “Spec-Finder” book method of matching spectrograms with those in
sample of unknown composition, to correlate type of structure
its catalog.
D
National Research Council-NBS Committee on Spectral Absorption Data,
withabsorptionbandpositions,tolocatespectraofcompounds
National Bureau of Standards, Washington, D. C. 20025. Card file.
having given structural features in common, and in other ways
E
The DMS System, Butterworth Scientific Publications, London WC2. Distrib-
that are too numerous to include here.
uted in U. S. by Butterworth, Inc., 7235 Wisconsin Ave., Washington, D. C. 20014.
F
CoblentzSocietySpectra, sold by Sadtler Research Laboratories. 3316 Spring
5.3 Spectral and chemical data from the user’s own labora-
Garden St., Philadelphia, Pa. 19104 and The Coblentz Society, Inc., P.O. Box
tory may be coded in a compatible system from details given
9952, Kirkwood, MO 63122.
G
in subsequent sections.
Chemical Manufacturer’s Association (CMA) 1825 Connecticut Ave., N. W.,
Washington, D. C. Loose-leaf. Spectra are no longer available from CMA.
5.4 Molecular formula-name tabulations comprise comple-
H
Infrared Data Committee of Japan, Sanyo Shuppan Doeki Co., Inc., Hoyu
mentary data systems for use in conjunction with the spectral
Bldg., 8, 2-chrome, Takaracho, Chuo-ku, Tokyo, Japan. Card file distributed in U.
band codes and chemical classification tapes. These carry the S. by Preston Technical Abstracts Co., 1718 Sherman Ave., Evanston, Ill.
I
The Aldrich Library of Infrared Spectra, Aldrich Chemical Co., 940 N. St. Paul
molecular formulas, chemical names, and reference serial
St., Milwaukee, Wis. 53233.
numbers for the compounds included in the indexes described
in 5.1 and 5.2. The tapes are commercially available and the
6.4 The chemical classification code is in columns 32
indexes have been published in book form as alphabetical,
through 57, and columns 58 through 62 provide for coding the
numerical, and molecular formula indexes (11,12,13). These
number of C, N, O, and S atoms in the compound under
books enable one to determine the name of the compound
consideration.Amelting or boiling point is coded in 63 to 65.
involved from a knowledge of the serial number of a spectro-
The rest of the card provides space for the private use of
gram or to locate a published standard spectrogram for a
individual laboratories and the identification of the source of
compound when the name is known.The serial-number listing
the coded data. The codes concerned with each of these areas
permits one to obtain the names of possible solutions to
are discussed separately.
analytical problems from spectra serial numbers produced by
search operations even though complete files of standard
CODING OF INFRARED ABSORPTION BANDS
spectra(aslistedinTable1)arenotathand.Oftenthenameof
(COLUMNS 1 THROUGH 25)
the compound together with other available information will
suffice; however, it is desirable to have as many standard
7. Codes forAbsorption Band Positions
spectra as feasible on hand for detailed study and comparison,
7.1 Columns 1 to 15 of “A” Cards (Note)—Coding is done
because positive identification depends upon matching the
in terms of wavelength in micrometres. From columns 1
unknown spectrum with one from published material or one
through 15, the column number is taken as the whole number
obtained from a bona fide sample of the compound. The
valueoftheabsorptionband,andthefractionalpartisrounded
molecular formula and alphabetical indexes are useful for
to the nearest 0.1 µm (values ending in five hundredths are
accessing band data for a suspected answer to an unknown.
considered as next higher tenths) and the number correspond-
ing to the 0.1 µm value is added to the number of the column.
6. General
Thus a band at 7.38 µm is coded to correspond to position 4 in
6.1 The system described below is designed to handle the
column 7, for a value of 7.4. The coding resolution of 0.1 µm
spectral absorption data obtained in the spectral range from 2
has been found to be adequate for searching and correlating
to 16 µm, and the system provides for a band-position coding
published spectra.
resolution of 0.1 µm.
NOTE 1—“A” is the designation for rock salt region infrared data (see
6.2 The original coding was on an IBM card format. The
18.4).
numerical values therefore correspond to columns and rows.
See Fig. 1. 7.2 Columns 1 to 25 of “G” for Far-Infrared—The coding
6.3 Columns 1 through 15 are used for coding absorption offar-infraredabsorptionbandsisdoneintermsofwavelength
band positions. in micrometres. The whole number value of the band position
E 204 – 98 (2002)
FIG. 1 Infrared Spectral Data Card
isobtainedbyadding10tothecolumnnumberandthenearest adjacent background (not necessarily at 100% transmittance);
tenthofamicrometreisrepresentedbythedecimalvaluetothe or if the strongest band is between 5 and 20% transmittance,
nearest tenth. Thus, a band at 18.57 µm is coded as 8.6. bands are coded which have 80% or less transmittance as
7.3 To indicate the range of data covered by the spectro- measured from a reasonably adjacent background. Thus, to be
gram, an “x” code is coded for each column that codes a coded, a band stands out from its adjacent background, at least
spectral range where no data are available. This is to distin- on one side, by 20 to 30% transmittance on the chart.
guish such regions from those in the spectrogram that have Therefore,“ shoulders” and weak bands on the sides of strong
been examined and found to contain no bands of sufficient bands are not coded. Likewise, bands whose percent transmit-
intensity to code, or to mark those regions where the spectral tance may be as low as 60 to 50 as read from the chart, but
data are obscured by strong solvent bands.Additionally, a “y” whichextendfrombackgroundshavingtransmittancevaluesof
code is added to each column that indexes a very strong band. 80to70%,arenotcoded.SomeexamplesareprovidedinFig.
The coding of such strong bands is limited to a very few, 2.
usually about three, which may be expected to persist in the 8.3 Searching absorption band data is much the same as
spectrum of a considerably diluted sample of the material. Use coding the bands. First, the spectrogram of the unknown
of such codes may be made in the analysis of mixtures where material should have its strongest bands between 1 and 20%
individual components may be present in relatively low con- transmittancesinceitistobecomparedwithdatacodedonthat
centrations so that only the strongest bands are readily detect- basis. Then one proceeds by two different methods depending
able. upon whether the unknown is a single component or is a
mixture of two or more components in roughly equivalent
8. Criteria for the Selection of Bands to be Coded
amounts.Intheformercase,positivesearchingonthebandsis
in order, while the latter case requires that negative inputs be
8.1 Experience has shown that it is not desirable to code all
included in the search request. Each method is discussed
ofthebandsofmostspectra.Majorandmediumstrengthbands
briefly in Sections 9 and 10.
are coded to identify the compounds uniquely. However,
8.4 The optimum combination of searching techniques de-
codingoftoomanyweakbandsminimizestheeffectivenessof
pends upon the computer algorithm used. Instructions specific
negative searching, which is valuable for mixtures. Therefore,
for each program should be followed.
theselectionofwhichbandstocodeandwhichtoomitrequires
some judgment; and because of the nature of published
9. Positive Searching for Individual Spectra
spectrograms,thejudgingcanbeguidedonlybyratherflexible
rules. Several factors enter into the determination of the 9.1 In this method, the search data are selected with the
strength of an absorption band, and what may be a good set of expectation that all or most of the bands in the unknown
factorsfortheproductionofanexcellentspectrogramfromone spectrogram are caused by a single compound. Search pro-
material is not necessarily a good set to provide a spectrogram grams vary, but it is desirable that they include provisions for
from another materi
...