ASTM E334-01

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Designation: E 334 – 01
Standard Practice for
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General Techniques of Infrared Microanalysis
This standard is issued under the fixed designation E334; 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 larly severe in micro work. For example, minor impurities in a
solvent can become major components of a residue remaining
1.1 Thispracticecoverstechniquesthatareofgeneralusein
after solvent evaporation. Materials extracted from thin-layer
securing and analyzing microgram quantities of samples by
chromatographic materials, from the paper used in paper
infrared spectrophotometric techniques. This practice makes
chromatography, and from solid adsorbents in general, may
repetition of description of specific techniques unnecessary in
include particular contaminants of concern. It should also be
individual infrared methods.
noted that the gas-chromatographic stationary phase may lead
1.2 These recommendations are supplementary to Practices
to significant contamination. Consideration of these and other
E168, E573, and E1252, which should be referred to for
sources of contamination must always enter interpretation of
theory, general techniques of sample preparation, and calcula-
results in microanalysis. Erroneous results can be minimized
tions.
by the use of pure reagents, extreme care in sample handling,
2. Referenced Documents andthefrequentuseof“blanks”inthecourseofseparationand
subsequent recording of spectra.
2.1 ASTM Standards:
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E131 Terminology Relating to Molecular Spectroscopy
5. General Microspectroscopic Techniques
E168 Practices for General Techniques of Infrared Quanti-
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5.1 Spectroscopic techniques used for the examination of
tative Analysis
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microsamples are usually adaptations of comparable macro
E573 Practices for Internal Reflection Spectroscopy
techniques, and many have been described in the literature (1,
E1252 Practice for General Techniques for Obtaining In-
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2
2).
frared Spectra for Qualitative Analysis
5.2 In computerized dispersive spectrometers or Fourier
E1642 PracticeforGeneralTechniquesofGasChromatog-
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transform-infrared (FT-IR) instruments, computer routines for
raphy Infrared (GC/IR) Analysis
multiple scanning, signal averaging, absorbance subtraction,
E2105 Practice for General Techniques of Thermogravi-
andscaleexpansioncanbeusedveryeffectivelytoenhancethe
metric Analysis (TGA) Coupled with Infrared Analysis
2 observed signal-to-noise ratio of weak bands and increase
(TGA/IR)
sensitivity (3, 4). Absorbance subtraction is also commonly
E 2106 Practice for General Techniques of Liquid
usedtoeliminateinterferingbandsfromthesamplematrixand
Chromatography-Infrared (LC/IR) and Size Exclusion
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thus lower the limits of detection (see Practice E168).
Chromatography (SEC/IR) Analysis
5.3 Use of Masking Apertures—The aperture of sample
3. Terminology
holders used for microspectroscopic study (without the use of
an infrared microscope) are usually significantly smaller than
3.1 Definitions and Symbols—For definitions of terms and
the beam at the sample position of the instrument. As a
symbols, refer to Terminology E131.
consequenceofthesesmallapertures,stepsneedtobetakento
3.2 Beam Condenser—Aspecializedaccessorydesignedfor
ensure that the best quality spectra be obtained, and the
analysis of samples of a microgram or less, comprising an
techniques used will depend on the type of spectrometer being
analyte area or volume of 2.0 mm diameter or less.
used. In general, the use of a beam condensing accessory will
4. Contamination
greatly improve the results obtained (see 5.4).
5.3.1 When a double-beam dispersive spectrometer that is
4.1 Although the presence of contaminants is a general
not equipped for control by minicomputer is used, the refer-
problem in any type of analysis, contamination can be particu-
encebeamshouldbemaskedtoacorrespondingaperture.This
can be accomplished by using an opaque sheet of stiff material
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This practice is under the jurisdiction ofASTM Committee E13 on Molecular punched with an appropriate opening, with reference screens,
Spectroscopy and is the direct responsibility of Subcommittee E13.03 on Infrared
Spectroscopy.
Current edition approved Feb. 10, 2001. Published April 2001. Originally
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published as E334–90. Last previous edition E334–96. The boldface numbers in parentheses refer to a list of references at the end of
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Annual Book of ASTM Standards, Vol 03.06. this practice.
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