GB/T 9722-2023 English PDF (GBT9722-2023)

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GB/T 9722-2023: Chemical reagent - General rules for the gas chromatography
GB/T 9722-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.040.30
CCS G 60
Replacing GB/T 9722-2006
Chemical Reagent - General Rules for the Gas
Chromatography
ISSUED ON: AUGUST 6, 2023
IMPLEMENTED ON: MARCH 1, 2024
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative References ... 5
3 Terms and Definitions ... 5
4 Method and Principle ... 6
5 Reagents and Materials ... 6
6 Instruments ... 6
7 Test Conditions ... 7
8 Operating Method ... 8
9 Qualitative Analysis ... 11
10 Quantitative Analysis ... 12
11 Method Error ... 17
12 Data Quality Assurance ... 18
13 Environmental Requirements, Safety Precautions and Waste Disposal ... 19
Appendix A (informative) Chromatographic Columns ... 21
Appendix B (normative) Illustrations and Calculation Formulas of Related Terms ... 24
Appendix C (informative) Acceptable Ranges of Precision and Trueness of the Method
... 26
Bibliography ... 27
Chemical Reagent - General Rules for the Gas
Chromatography
1 Scope
This document specifies the instrument requirements and analytical methods for the gas
chromatography for chemical reagent.
This document is applicable to the determination of main components and impurities of organic
chemical reagents containing volatile components.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB/T 4946 Terms of Gas Chromatography
GB 4962 Technical Safety Regulation for Gaseous Hydrogen Use
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and Judgement of
Limiting Values
JJG 700 Gas Chromatographs
TSG 23-2021 Regulation on Safety Technology for Gas Cylinder
3 Terms and Definitions
What is defined in GB/T 4946, and the following terms and definitions are applicable to this
document.
3.1 asymmetric factor
A parameter that describes the degree of asymmetry of a chromatographic peak.
3.2 height of an effective plate
The length of unit effective plate.
4 Method and Principle
After the sample and its components being determined are vaporized, they enter the
chromatographic column at the same time with the carrier gas. The difference in physical and
chemical properties, such as: adsorption or dissolution, desorption or analysis of each
component being determined between the gas-solid or gas-liquid phases is used to form a
difference in the migration speed of the components in the column for separation. After
separation, each component flows out of the chromatographic column and enters the detector.
The data processing system records the chromatogram and corresponding data. The retention
value and chromatographic peak area or corresponding peak height value of each component
are respectively used as the basis for qualitative and quantitative analysis.
5 Reagents and Materials
5.1 Standard Sample
The mass fraction of the main body content of the standard sample shall not be lower than
99.9%. When high-purity standard samples cannot be obtained for special substances, standard
samples with clarified main body content shall be used.
5.2 Reference Substance
The reference substance shall be traceable to International System of Units (SI) or certified
reference substance.
5.3 Carrier Gas
The purity is not lower than 99.99%. Before use, dehydration devices (silica gel and molecular
sieve), activated carbon and deoxidizer, etc. shall be used for purification.
5.4 Combustion Gas
The purity is not lower than 99.99%. Before use, dehydration devices (silica gel and molecular
sieve), activated carbon and deoxidizer, etc. shall be used for purification.
5.5 Air
It does not contain dust, hydrocarbons, moisture and corrosive substances that may affect the
normal operation of the instrument. Before use, dehydration devices (silica gel and molecular
sieve) and activated carbon, etc. shall be used for purification.
6 Instruments
6.1 Composition of Gas Chromatograph
stationary phase, column length, inner diameter and liquid film thickness;
d) Temperature: chromatographic column temperature, vaporization chamber
temperature and detection chamber temperature;
e) Sample injection volume: shall be controlled within a linear response range; when
using the normalization method, the main peak height shall be above 70% of the
measuring range;
f) Split ratio, make-up and other instrument conditions;
g) Height of an effective plate: the calculation method is in accordance with the
stipulations of Appendix B, and two significant figures are retained;
h) Relative retention value: retained to two decimal places;
i) Degree of separation: retain two significant figures;
j) Asymmetric factor: the calculation method is in accordance with the stipulations of
Appendix B, and two significant figures are retained;
k) Quantitative method.
NOTE: the separation of difficult-to-separate substances and the retention values relative to the
main body can be determined as required. The carrier gas flow rate, column temperature,
vaporization chamber temperature, split ratio, make-up and sample injection volume
conditions can be appropriately adjusted in accordance with the specific instrument
performance during operation.
8 Operating Method
8.1 Peak Height Measurement
Draw a vertical line from the top of the peak to the bottom of the peak. The distance from the
point where the vertical line intersects with the upper edge of the chromatographic peak baseline
to the top is the peak height (h). Or calculate the difference between the signal value at the peak
apex and the baseline signal value at the same retention time as the peak apex (see Figure 2).
value of each component relative to the reference component (a certain component in the
sample to be tested). The components with the same relative retention value can be identified
as the same substance.
The relative retention value ri,s is calculated in accordance with Formula (1):
Where,
tR(i)---the adjusted retention time of each component, expressed in (min);
tR(s)---the adjusted retention time of the reference component, expressed in (min);
tR(i)---the retention time of each component, expressed in (min);
tM---the dead time, expressed in (min);
tR(s)---the retention time of the reference component, expressed in (min).
9.2.2 If the standard sample cannot be obtained, the relative retention value of the known
substance can be obtained by searching the literature, then, under the test conditions (column
temperature, stationary phase and reference substance) provided by the literature value,
determine the relative retention value of the sample to be tested; if it is consistent with the
literature value, it can be identified as the same substance.
10 Quantitative Analysis
10.1 Correction Factor
10.1.1 General requirements
This document adopts a mass correction factor for component i relative to the main body.
For individual components listed in technical indicators, the mass correction factor will be used
regardless of the mass frac...