GB/T 6040-2019 (GB/T6040-2019, GBT 6040-2019, GBT6040-2019) & related versions
GB/T 6040-2019: PDF in English (GBT 6040-2019)
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, highly soluble solvent such as methanol, acetone, or
trichloromethane to dissolve the sample. The sample solution is dropped
on the infrared permeable material plate, expanded. After the solvent is
volatilized, a thin film is obtained.
b) A thermally-stable thermoplastic solid sample is sandwiched between two
heating plates and pressed to form a thin film.
c) When it is desired not to change the shape of sample as much as possible,
USE a microtome to slice it.
d) For a sample having elasticity such as a rubbery shape or a foamed shape,
it is measured by pressurization into a thin film shape using a rhombus
frame.
black-body radiation of sample at the same temperature, to correct the
intensity of spectrum.
e) Photoacoustic spectrometry: FILL the sample cell with the sample. When
the amount of sample is too small, it shall be enriched using a matrix such
as potassium bromide powder. The shape of sample has little effect on
the determination, but when the space inside the sample cell is too large,
the signal-to-noise ratio deteriorates.
f) GC-IR determination: SELECT a solvent which matches the polarity of
sample and has a high solubility to dissolve the sample.
g) LC-IR determination: SELECT the LC mobile phase with less infrared
absorption and matching the polarity of sample to dissolve the sample.
h) TG-IR determination: When the sample is in the form of lumps or granules,
the sample shall be powdered, to ensure accurate measurement.
5.3 Preparation methods of powder sample
5.3.1 Tableting method: Same as 5.2.2.
5.3.2 Solution method: Same as 5.2.3.
5.3.3 Paste method: The powder sample is mixed and ground with the liquid
paraffin. The paste is sandwiched between two salt tablets.
5.3.4 Other methods: When using accessories, except for the following
methods, refer to the operating instructions for the accessories.
a) Diffuse reflectance method: The sample is pulverized into a powder having
a grain size of several tens of micrometers or less; and laid flat on a
sample dish. In order to reduce the influence of specular reflected light,
potassium bromide, potassium chloride, or potassium fluoride powder is
usually mixed.
b) Photoacoustic spectroscopy: Same as 5.2.5 e).
c) GC-IR method: Same as 5.2.5 f).
d) LC-IR method: Same as 5.2.5 g).
e) TG-IR method: Same as 5.2.5 h).
5.4 Preparation methods of liquid sample
6.3.6 Repeatability: Under the same conditions, in a short period of time, the
same stable sample is measured twice or more, to confirm that the deviation of
measured values of wavenumber and transmittance is within a prescribed
range.
7 Qualitative analysis
This clause specifies qualitative analysis methods using absorption spectrum.
7.1 Qualitative analysis using infrared spectroscopy includes absorption
spectrum analytic method and method for comparison with known compound
spectrum.
7.1.1 The absorption spectrum analytic method is, based on the fact that each
functional group or atomic group has an absorption in a specific wavenumber
range, to compare the coincidence of the measured absorption spectrum with
the specific absorption, and to speculate and analyze whether or not a known
functional group or atomic group showing a specific absorption exists in the
substance under determination.
7.1.2 The method for comparison with known compound spectrum is to
compare the similarity of the absorption spectrum of the sample under
determination to the absorption spectrum or the standard spectrogram of the
known pure compound, to characterize the compound.
7.2 When using the above methods to confirm a chemical substance or using
a functional group or atomic group information to speculate a partial structure,
it shall pay attention to the following matters.
7.2.1 USE characteristic absorption table and data set for analysis. When
speculating, it shall be noted that the infrared absorption of functional group and
atomic group of the substance under determination is affected by the atoms,
molecules, etc. adjacent thereto; and the position, intensity, and shape of
absorption peak will change.
7.2.2 USE information on known chemical properties, physicochemical
properties, analytical chemistry, etc.
7.2.3 It is difficult to perform qualitative analysis of mixture using only infrared
absorption spectral analysis. Chromatography shall be used to separate the
mixture into a single component. Combined with information obtained by other
analytical chemistry means, analysis shall be performed.
7.2.4 When confirming a compound or using a partial structure to speculate a
compound, it shall be compared with the absorption spectrum measured under
associated with the spectroscopic data of the sample under determination.
Calculate the concentration of each component.
8.2.2.2 Factor analysis method: The main component is subjected to matrix
transformation by using spectroscopic data group obtained by regression
analysis method or PLS regression analysis method, to determine a few
quantitatively-necessary spectroscopic data, remove unnecessary factors
caused by noise, find the relationship between parameters and concentration,
and calculate the concentration of each component.
9 Safety and maintenance
9.1 Safety: In order to ensure the use safety of the apparatus, the operating
instruction must be read carefully. It shall be familiar with the relevant laws and
regulations, master the characteristics of chemical substances, and strengthen
the training of operators. In addition, the following matters must be noted.
9.1.1 When the instrument is powered, do not touch the high-voltage part and
the live part. Attention must be paid to adequate insulation and grounding.
9.1.2 Avoid looking directly at the laser.
9.1.3 In accordance with the high-pressure gas treatment method, the high-
pressure gas is operated.
9.1.4 When using liquid nitrogen, protective equipment must be used, to avoid
inhalation of high concentrations of gas.
9.1.5 PAY close attention to the safe use of window materials such as thallium,
selenium, and arsenic compounds, various hazardous solvents such as halides
and carbon disulfide, and the samples. When discarding, perform proper
disposal.
9.2 Maintenance: Confirm that the installation site meets the conditions listed
in 6.1. SET inspection items, maintenance items, contents, time, etc.; and
CHECK on time.
10 Collating of determination results
According to the following items, the determination results are collated:
a) Date of determination;
b) Name of measurer;
......
| Standard ID | GB/T 6040-2019 (GB/T6040-2019) | | Description (Translated English) | General rules for infrared analysis | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | G15 | | Classification of International Standard | 71.040.40 | | Word Count Estimation | 18,145 | | Date of Issue | 2019-06-04 | | Date of Implementation | 2020-05-01 | | Drafting Organization | China Petrochemical Corporation Beijing Research Institute of Chemical Industry, Shanghai Metrology and Testing Technology Research Institute, Guangzhou Zhongke Testing Technology Service Co., Ltd., Quzhou Fluorosilicon Technology Research Institute | | Administrative Organization | Organic Chemical Sub-Technical Committee of National Chemical Standardization Technical Committee (SAC/TC 63/SC 2) | | Proposing organization | China Petroleum and Chemical Industry Federation | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration |
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