GB/T 6040-2002 English PDF (GBT6040-2002)

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GB/T 6040-2002: General rules for infrared analysis
GB/T 6040-2002
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.040.40
G 04
Replacing GB/T 6040-1985
General rules for infrared analysis
ISSUED ON: SEPTEMBER 24, 2002
IMPLEMENTED ON: APRIL 01, 2003
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Reference standards ... 4 
3 Definitions ... 4 
4 Apparatus ... 6 
5 Methods of sample preparation ... 13 
6 Operation methods ... 16 
7 Qualitative analysis ... 19 
8 Quantitative analysis ... 20 
9 Safety and maintenance ... 21 
10 Collating of determination results ... 21 
General rules for infrared analysis
1 Scope
This Standard specifies the general rules for the quantitative or quantitative
analysis of organic and inorganic substances using infrared spectrometer
absorption spectrometry.
This Standard applies to infrared analysis with a wavenumber range of 4000
cm-1~400 cm-1 (wavelength 2.5 μm~25 μm).
2 Reference standards
The following standards contain provisions which, through reference in this
Standard, constitute provisions of this Standard. At the time of publication of
this Standard, the editions shown are valid. All standards will be revised. The
parties using this Standard shall investigate whether the latest editions of the
following standards are applicable.
GB/T 7764-2001 Rubber - Identification - Infra-red spectrometric method
GB/T 14666-1993 Terms for Analytical Chemistry
3 Definitions
The definitions of the main terms covered by this Standard, in addition to those
specified in GB/T 14666, include the following definitions:
3.1 Transmittance
The ratio OF the radiant energy transmitted through the sample TO the incident
radiant energy.
3.2 Baseline
A straight line or curve drawn in a certain way on the absorption spectrum,
which is used to represent the background absorption curve in the absence of
absorption band.
3.3 Sample thickness
difference calculation, baseline correction, kubelka-munk transformation,
kramers-kroning transformation, spectroscopic data retrieval, etc.
4.2.1.6 Display record: DISPLAY the analysis result and data processing result
on the screen. It consists of display and recorder.
4.2.2 Dispersive infrared spectrometer
4.2.2.1 Light source: Same as 4.2.1.1.
4.2.2.2 Sample chamber: The sample chamber consists of a sample cell, a
sample holder, and a sample holder for assembling accessories. The dispersive
infrared spectrometer is usually a double-beam spectrometer. The sample
optical path and the reference optical path are respectively provided with a
sample holder.
4.2.2.3 Spectrophotometric part: It consists of dimmer, optical splitter, detector,
amplifier, calculator, etc. The optical system of the dispersive infrared
spectrometer (optical zero method) is shown in Figure 5.
a) Dimmer: An optical element used for dimming in the optical zero method.
It is set in the reference optical path, to adjust the intensity of the beam
passing through the reference optical path to be almost the same as the
intensity of the beam passing through the sample optical path.
b) Fan-type mirror: A rotating mirror which switches the sample beam and
the reference beam.
c) Optical splitter: An optical system consisting of a slit, a reflector, and a
dispersing element. The dispersing element uses a prism, a diffraction
grating, or an optical element thereof. A diffraction grating is usually used.
d) Detector: CONVERT the intensity of incident light into an electric signal. A
vacuum thermocouple, a thermoelectric detector, or a semiconductor
detector, etc. is usually used.
e) Amplifier: To process the signal conveniently, amplify the signal obtained
by the detector. In the optical zero method, it consists of a preamplifier, a
main amplifier, a synchronous rectifier, a modulator, and a power amplifier.
f) Calculator: In the signal processing system using the electric ratio method,
the electric signal of sample beam is separated from the electric signal of
reference beam. The intensity ratio of the two signals is calculated.
4.3.6 Temperature change cell: A sample cell used to determine the infrared
absorption of a sample at various temperatures, which can change the sample
temperature.
4.3.7 ATR measuring device: A device used to measure the high-absorption
sample or sample surface.
4.3.8 Diffuse reflection measuring device: A device for directly measuring a
powder sample.
4.3.9 Reflection measuring device: A device for measuring the reflection
spectrum, which has the following two types:
a) Reflection measuring device: A device for determining the specular
reflection spectrum of a substance having an infrared reflecting surface by
means of reflectance spectroscopy.
b) High-sensitivity reflection measuring device: A device used for high-
sensitivity measurement of samples with high reflectivity and smooth
surface.
4.3.10 Radiation measuring device: A device for determining the radiation
spectrum of a heated sample.
4.3.11 Photoacoustic spectrometric device: A measuring device using a
photoacoustic detector when measuring a high-scattering sample or a sample
which is difficult to prepare.
4.3.12 Microscopic infrared measuring device: A device for measuring a very
small amount of sample, which can perform transmittance, reflection, ATR, and
high-sensitivity reflection measurement by changing the optical path and the
optical mirror.
4.3.13 Gas chromatography infrared (GC-IR) combined device: A device which
uses infrared analysis for components separated by a gas chromatographic
column.
4.3.14 Liquid chromatography infrared (LC-IR) combined device: A device
which uses infrared analysis for components separated by a liquid
chromatographic column.
4.3.15 Thermogravimetric infrared (TG-IR) measuring device: A device which
uses infrared analysis for the gas component generated by a thermogravimetric
device.
4.4 Additional functions
4.4.14 Quantitative calculation: The function of using the absorption intensity to
calculate the concentration of a component.
4.4.15 Data storage: The function of saving measurement results and data
processing results.
5 Methods of sample preparation
This clause specifies the precautions for sample preparation methods for the
determination of solid, powder, liquid, and gas samples.
When using an accessory device or performing the determination of reflection,
radiation, photoacoustic spectroscopy, TG-IR, GC-IR, LC-IR, etc., sample
preparation shall be performed according to the instrument’s operating
instruction.
5.1 General precautions: When performing infrared analysis, according to the
analysis purpose, sample state, analytical method, and the performance of
measuring device, the appropriate sample preparation method must be
selected. For qualitative analysis, the concentration of sample shall be adjusted
so that the transmittance of the strongest absorption band of the sample is
1%~10%. For quantitative analysis, the appropriate sample concentration,
sample thickness, and optical path length of sample cell shall be selected, so
that the relationship between the absorbance of the measured absorption band
and the sample concentration is in a linear relationship.
5.2 Preparation methods of solid sample
5.2.1 Thin-film method: There are the following four methods.
a) USE a volatile, high...