ASTM E204-98(2007)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E204 −98(Reapproved2007)
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope E168Practices for General Techniques of Infrared Quanti-
tative Analysis
1.1 These practices cover a data system generated from
E932PracticeforDescribingandMeasuringPerformanceof
1955 through 1974. It is in world-wide use as the largest
Dispersive Infrared Spectrometers
publicly available data base. It is recognized that it does not
E1252Practice for General Techniques for Obtaining Infra-
represent the optimum way to generate a new data base with
red Spectra for Qualitative Analysis
the most modern computerized equipment.
1.2 Thesepracticesdescribeproceduresforidentificationof
3. Summary of Practices
individual chemical substances using infrared absorption spec-
3.1 Arepresentativesampleofthematerialtobeanalyzedis
troscopy and band indexes of spectral data. Use of absorption
separated into its individual components, if required, and each
spectroscopy for qualitative analysis has been described by
component is introduced into a suitable sample cell or matrix,
many (1-8), but the rapid matching of the spectrogram of a
mainly according to its physical state. The spectrum is re-
sample with a spectral data in the literature by use of a band
corded over a characterizing range. The choice of spectral
index system designed for machine sorting was contributed by
range and instrument is dictated by a general consideration of
Kuentzel (9).ItisonKuentzel’ssystemthattheASTMindexes
the chemical nature of the sample (3-5).Anote is made of the
of absorption spectral data are based.
spectral positions of prominent absorption bands and,
1.3 Use of these practices requires, in addition to a record-
optionally, of known chemical and physical properties of the
ingspectrometerandaccesstopublishedreferencespectra,the
material. The qualitative chemical composition of the material
encoded data and suitable data handling equipment.
may then be identified by searching the coded data file for
compoundshavingmatchingcharacteristics.Detailsonsearch-
1.4 This standard does not purport to address all of the
ingproceduresareavailableelsewhere. Detailsofthecodeare
safety concerns, if any, associated with its use. It is the
in the following sections.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Apparatus
bility of regulatory limitations prior to use.
4.1 Infrared Spectrophotometer—Aspectrophotometer with
2. Referenced Documents
capabilities equivalent to an instrument with a rock salt prism
operated under parameters compatible withAnalytical Spectra
2.1 ASTM Standards:
(8, 10) and with wavelength accuracy to 0.05 µm by compari-
son with the indene spectrum in Practice E932.
These practices are under the jurisdiction of ASTM Committee E13 on
4.2 Laboratory procedures for obtaining spectra are de-
Molecular Spectroscopy and Separation Science and are the direct responsibility of
scribed in Refs (3-5) and in Practices E168, and E1252.
Subcommittee E13.03 on Infrared and Near Infrared Spectroscopy.
Current edition approved Dec. 1, 2007. Published December 2007. Originally
4.3 Data-Handling Equipment—It is possible to convert
approved in 1962. Last previous edition approved in 2002 as E204-98(2002).
data on the ASTM magnetic tape to IBM cards, and to use
DOI: 10.1520/E0204-98R07.
2 sorters or collators to manipulate the data. However, the file is
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
these practices.
large and it is more efficient, and with good software, more
The ASTM Infrared Spectral Index, AMD 33 and its supplements may be
effective, to use computers. These may be either dedicated or
purchased in the form of magnetic tapes, from Sadtler Research Labs., Inc., 3316
Spring Garden St., Philadelphia, PA 19104.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Publicly available systems are as follows: IRGO, Chemir Labs., 761 W.
Standards volume information, refer to the standard’s Document Summary page on Kirkham, St. Louis, MO 63122; SPIR (Canada only), National Research Council,
the ASTM website. 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
E204−98(2007)
TABLE 1 Catalogs of Spectrograms Covered by ASTM Punched
time-shared. Thus, the minimum equipment requirement is a
Cards Indexing Infrared Absorption Data
computer, a program, and the coded data (and either batch
A
A API Research Project 44
processing facilities) or a teletypewriter or terminal with
B
B User’s own file of spectrograms
modem for accessing these resources for interactive searches.
C
C Sadtler catalog of spectrograms
D
D NRC-NBS file of spectrograms
5. Index
E Literature
E
F Documentation of Molecular Spectroscopy
5.1 The index data on approximately 145 000 spectra are
F
G Coblentz Society Spectrograms
G
availableonmagnetictape.Themainabsorptionbandsofeach
H Chemical Manufacturer’s Association (CMA)
H
spectrum are coded to the nearest 0.1 µm. J Infrared Data Committee of Japan
I
K Aldrich Library of Infrared Spectra , 1970 Edition
5.2 In addition to the code for spectral data of chemical
A
American Petroleum Institute, Research Project 44, Infrared and Ultraviolet
substances, there are codes for chemical-structure
Spectral Data, Texas Agricultural and Mechanical College, College Station, TX,
classification, empirical formula, melting or boiling point, and 1943 to date. Loose-leaf.
B
Users are encouraged to submit spectrograms (or the pure compound in some
serial number reference. Other codes include data on sample
cases) to one of the other organizations listed. It is unlikely that any individual
state, wavelength intervals of strongest bands, and no-data
laboratory can code its spectral data and punch cards at the cost of the ASTM
areas.Foragivensubstance,thecodedspectraldataarealmost cards (about one cent each).
C
StandardandCommercialSpectra, Sadtler Research Laboratories, 3316 Spring
invariablyuniqueasisthepatternforcodedchemicalstructure
Garden St., Philadelphia, Pa. 19104. Loose-leaf. The Sadtler organization also
and physical properties. Variables may be searched in any
offers a “Spec-Finder” book method of matching spectrograms with those in its
catalog.
desired combination to locate a standard spectrum similar to
D
National Research Council-NBS Committee on Spectral Absorption Data, Na-
that of a sample of unknown composition, to correlate type of
tional Bureau of Standards, Washington, D. C. 20025. Card file.
E
structure with absorption band positions, to locate spectra of
TheDMSSystem, Butterworth Scientific Publications, London WC2. Distributed
in U. S. by Butterworth, Inc., 7235 Wisconsin Ave., Washington, D. C. 20014.
compoundshavinggivenstructuralfeaturesincommon,andin
F
Coblentz Society Spectra, sold by Sadtler Research Laboratories. 3316 Spring
other ways that are too numerous to include here.
Garden St., Philadelphia, Pa. 19104 and The Coblentz Society, Inc., P.O. Box
9952, Kirkwood, MO 63122.
5.3 Spectral and chemical data from the user’s own labora-
G
Chemical Manufacturer’s Association (CMA) 1825 Connecticut Ave., N. W.,
tory may be coded in a compatible system from details given
Washington, D. C. Loose-leaf. Spectra are no longer available from CMA.
H
in subsequent sections. Infrared Data Committee of Japan, Sanyo Shuppan Doeki Co., Inc., Hoyu Bldg.,
8, 2-chrome, Takaracho, Chuo-ku, Tokyo, Japan. Card file distributed in U. S. by
5.4 Molecular formula-name tabulations comprise comple-
Preston Technical Abstracts Co., 1718 Sherman Ave., Evanston, Ill.
I
The Aldrich Library of Infrared Spectra, Aldrich Chemical Co., 940 N. St. Paul St.,
mentary data systems for use in conjunction with the spectral
Milwaukee, Wis. 53233.
band codes and chemical classification tapes. These carry the
molecular formulas, chemical names, and reference serial
numbers for the compounds included in the indexes described
6.3 Columns 1 through 15 are used for coding absorption
in 5.1 and 5.2. The tapes are commercially available and the
band positions.
indexes have been published in book form as alphabetical,
numerical, and molecular formula indexes (11,12,13). These
6.4 The chemical classification code is in columns 32
books enable one to determine the name of the compound through 57, and columns 58 through 62 provide for coding the
involved from a knowledge of the serial number of a spectro-
number of C, N, O, and S atoms in the compound under
gram or to locate a published standard spectrogram for a
consideration.Amelting or boiling point is coded in 63 to 65.
compound when the name is known.The serial-number listing
The rest of the card provides space for the private use of
permits one to obtain the names of possible solutions to
individual laboratories and the identification of the source of
analytical problems from spectra serial numbers produced by
the coded data. The codes concerned with each of these areas
search operations even though complete files of standard
are discussed separately.
spectra(aslistedinTable1)arenotathand.Oftenthenameof
CODING OF INFRARED ABSORPTION BANDS
the compound together with other available information will
(COLUMNS 1 THROUGH 25)
suffice; however, it is desirable to have as many standard
spectra as feasible on hand for detailed study and comparison,
7. Codes for Absorption Band Positions
because positive identification depends upon matching the
7.1 Columns 1 to 15 of “A” Cards (Note)—Coding is done
unknown spectrum with one from published material or one
in terms of wavelength in micrometres. From columns 1
obtained from a bona fide sample of the compound. The
through 15, the column number is taken as the whole number
molecular formula and alphabetical indexes are useful for
valueoftheabsorptionband,andthefractionalpartisrounded
accessing band data for a suspected answer to an unknown.
to the nearest 0.1 µm (values ending in five hundredths are
6. General
considered as next higher tenths) and the number correspond-
6.1 The system described below is designed to handle the ing to the 0.1 µ m value is added to the number of the column.
spectral absorption data obtained in the spectral range from 2
Thus a band at 7.38µmis coded to correspond to position 4
to 16 µ m, and the system provides for a band-position coding incolumn7,foravalueof7.4.Thecodingresolutionof0.1µm
resolution of 0.1 µm.
has been found to be adequate for searching and correlating
published spectra.
6.2 The original coding was on an IBM card format. The
numerical values therefore correspond to columns and rows.
NOTE 1—“A” is the designation for rock salt region infrared data (see
See Fig. 1. 18.4).
E204−98(2007)
FIG. 1 Infrared Spectral Data Card
7.2 Columns 1 to 25 of “G” for Far-Infrared—The coding 8.2 As a general rule, bands selected to be coded have an
offar-infraredabsorptionbandsisdoneintermsofwavelength absorbance ratio with the strongest band in the spectrogram of
in micrometres. The whole number value of the band position 1:10 or more. This means that when the strongest band has
isobtainedbyadding10tothecolumnnumberandthenearest between 1 and 5% transmittance, bands are coded which have
tenthofamicrometreisrepresentedbythedecimalvaluetothe 70% or less transmittance as measured from a reasonably
nearest tenth. Thus, a band at 18.57 µm is coded as 8.6. adjacent background (not necessarily at 100% transmittance);
or if the strongest band is between 5 and 20% transmittance,
7.3 To indicate the range of data covered by the
bands are coded which have 80% or less transmittance as
spectrogram, an “x” code is coded for each column that codes
measured from a reasonably adjacent background. Thus, to be
a spectral range where no data are available. This is to
coded, a band stands out from its adjacent background, at least
distinguish such regions from those in the spectrogram that
on one side, by 20 to 30% transmittance on the chart.
havebeenexaminedandfoundtocontainnobandsofsufficient
Therefore,“ shoulders” and weak bands on the sides of strong
intensity to code, or to mark those regions where the spectral
bands are not coded. Likewise, bands whose percent transmit-
data are obscured by strong solvent bands.Additionally, a “y”
tance may be as low as 60 to 50 as read from the chart, but
code is added to each column that indexes a very strong band.
whichextendfrombackgroundshavingtransmittancevaluesof
The coding of such strong bands is limited to a very few,
80to70%,arenotcoded.SomeexamplesareprovidedinFig.
usually about three, which may be expected to persist in the
2.
spectrum of a considerably diluted sample of the material. Use
of such codes may be made in the analysis of mixtures where 8.3 Searching absorption band data is much the same as
individual components may be present in relatively low con- coding the bands. First, the spectrogram of the unknown
centrations so that only the strongest bands are readily detect- material should have its strongest bands between 1 and 20%
able. transmittancesinceitistobecomparedwithdatacodedonthat
basis. Then one proceeds by two different methods depending
8. Criteria for the Selection of Bands to be Coded upon whether the unknown is a single component or is a
mixture of two or more components in roughly equivalent
8.1 Experience has shown that it is not desirable to code all
amounts.Intheformercase,positivesearchingonthebandsis
ofthebandsofmostspectra.Majorandmediumstrengthbands
in order, while the latter case requires that negative inputs be
are coded to identify the compounds uniquely. However,
included in the search request. Each method is discussed
codingoftoomanyweakbandsminimizestheeffectivenessof
briefly in Sections 9 and 10.
negative searching, which is valuable for mixtures. Therefore,
theselectionofwhichbandstocodeandwhichtoomitrequires 8.4 The optimum combination of searching techniques de-
pends upon the computer algorithm used. Instructions specific
some judgment; and because of the nature of published
spectrograms,thejudgingcanbeguidedonlybyratherflexible for each program should be followed.
rules.
...