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GB/T 9722-2023 PDF in English


GB/T 9722-2023 (GB/T9722-2023, GBT 9722-2023, GBT9722-2023)
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GB/T 9722-2023English320 Add to Cart 0-9 seconds. Auto-delivery. Chemical reagent - General rules for the gas chromatography Valid
GB/T 9722-2006English225 Add to Cart 0-9 seconds. Auto-delivery. Chemical reagent -- General rules for the gas chromatography Obsolete
GB/T 9722-1988English439 Add to Cart 4 days Chemical reagent--General rules for the gas chromatography Obsolete
Standards related to (historical): GB/T 9722-2023
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GB/T 9722-2023: PDF in English (GBT 9722-2023)

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 & 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 fraction. Among the components to be determined, for homologues with relatively close carbon numbers or substances with small thermal conductivity differences, a correction factor may be added depending on the specific situation. 10.1.2 Determination of relative correction factor Use the weighing method (accurate to 0.1 mg) to prepare several standard solutions with similar indicators as the components being corrected and determine in accordance with the determination conditions of the sample. Round off the determination results with a confidence level of 95% and calculate the average value (retaining two significant figures). When adopting the standard addition method for quantitative analysis, the following requirements shall be satisfied: a) When adopting the internal standard method or external standard method for quantitative analysis, if there is no suitable internal standard substance, standard sample or solvent, the standard addition method can be adopted; b) The added amount of the component to be determined is close to the content of the component to be determined in the sample to be tested; c) The sample injection volume shall be within the linear range of the detector. The components to be determined shall all flow out under the test conditions; the same sample shall be repeatedly tested. Weigh-take an appropriate amount (accurate to 0.1 mg) of the sample to be tested and add a known amount of the component to be determined to prepare a standard calibration sample; in accordance with the same determination conditions, respectively determine the standard calibration sample and the sample to be tested. The mass fraction wi of the component determined by the standard addition method is calculated in accordance with Formula (6): Where, Ai---the peak area of the component i in the sample to be tested; ms---the mass of the added component i in the sample to be tested, expressed in (g); m---the mass of the sample to be tested, expressed in (g); Ai---after adding ms of the component i to the sample to be tested, the peak area of the component i. 10.6 Result Expression 10.6.1 The arithmetic mean of two repeated determination results shall be used as the test result, which shall be rounded in accordance with the stipulations of GB/T 8170. 10.6.2 When the mass fraction of the component to be tested is not less than 1%, the test result shall be accurate to 0.01% (mass fraction). 10.6.3 When the mass fraction of the component to be tested is not less than 0.01% and less than 1%, the test result shall be accurate to 0.001% (mass fraction). 10.6.4 When the mass fraction of the component to be tested is less than 0.01%, the test result mi---the mass of the added component i, expressed in (mg). 12 Data Quality Assurance 12.1 General Provisions Data quality control shall be implemented through regular analysis of quality control samples, determination of detection limit and quantitation limit, blank test and regular inspection of instrument performance, etc., so as to ensure the trueness and traceability of data. 12.2 Data Quality Control 12.2.1 Data quality shall be monitored by preparing quality control samples and regularly analyzing quality control samples. 12.2.2 Quality control samples can use standard samples, standard substances, reference substances or traceable test samples with known concentration; they shall be prepared in accordance with commonly encountered matrices, and their concentration shall be equivalent to the concentration of the component to be determined. Follow all the steps for pre-treatment and determination, and the recovery rate is between 80% ~ 120%. The determination results of quality control samples can also be analyzed and evaluated by establishing quality control charts. 12.2.3 The laboratory shall prepare a quality control sample and a blank sample for every batch of samples or every 20 samples. 12.3 Detection Limit and Quantitation Limit 12.3.1 Signal-to-noise ratio method Add the component to be determined with known concentration to the blank sample, prepare a sample with the minimum concentration that can be reliably detected. Under the same conditions, measure the signal (S) and baseline noise (N), and calculate the signal-to-noise ratio (S/N). When the signal-to-noise ratio (S/N) is 3, the corresponding concentration is the detection limit; when the signal-to-noise ratio (S/N) is 10, the corresponding concentration is the quantitation limit. 12.3.2 Blank standard deviation method Prepare a standard solution with the minimum concentration that can be reliably detected and draw a standard curve; determine the blank sample, and the number of determinations shall be no less than 10 times; calculate the standard deviation of the test results of the component to be determined in the blank sample. The determined value of the blank sample plus 3 times the standard deviation is the detection limit; the determined value of the blank sample plus 10 times the standard deviation is the quantitation limit. This is only applicable when the probability that the signal value of the interfering substance in the blank is higher than 3 times the standard deviation of the sample blank value is much less than 1%. 12.4 Blank Test Use the same sample processing method and test method as the sample to be tested to conduct a blank test. When performing a blank test with a blank sample, the influence of the sample matrix and the influence of the entire analytical operation can be distinguished; when performing a blank test with a pure solvent, the solvent blank can be separated from the influence of the equipment and the solvent blank can be obtained. 12.5 Regular Inspection of Instrument Performance Standard solutions with known concentrations shall be regularly prepared to confirm that the specified sensitivity, degree of separation, retention value and chromatogram can be obtained. Follow the operating manual provided by the manufacturer of the analytical instrument, check each component of the instrument at the specified frequency, and keep the inspection records. 13 Environmental Requirements, Safety Precautions and Waste Disposal 13.1 Environmental Requirements The environmental requirements shall satisfy the following conditions: a) The ambient temperature is 5 C ~ 35 C, the relative humidity is 20% ~ 80%, and the temperature and humidity will not drastically change; b) There is no strong electromagnetic field interference, no corrosive gas, no direct sunlight and no strong vibration; c) Power supply: AC voltage 220 V  22 V, frequency 50 Hz  0.5 Hz; d) The working environment shall be clean and dust-free, well-ventilated, and free of strong convection. 13.2 Safety Precautions The safety precautions of the laboratory shall comply with the following stipulations: a) The power supply of the instrument shall be well-grounded (ground resistance  4 ); b) The installation and acceptance of laboratory high-pressure gas cylinders shall be carried out in accordance with the stipulations of 8.6.9 and Chapter 9 in TSG 23-2021; c) When using hydrogen in the laboratory, it shall comply with the relevant stipulations performance. A.1.4 Liquid film thickness of chromatographic columns The liquid film thickness of the chromatographic columns has an impact on retention value, degree of separation, chromatographic column bleed, inertness and column capacity. Under constant-temperature conditions, the retention value of the solute is directly proportional to the liquid film thickness; thicker liquid film chromatographic columns obtain an equivalent or greater retention value at higher temperatures, and are generally used to analyze volatile compounds, such as: solvents and some gases; thinner liquid film chromatographic columns obtain an equivalent or smaller retention value at lower temperatures, and are generally used to analyze compounds with high boiling point or high molecular weight. Increasing the liquid film thickness improves the degree of separation of early eluting peaks, while possibly reducing the degree of separation of late eluting peaks. For a given stationary phase, column bleed increases with the increasing liquid film thickness. Chromatographic columns with thicker liquid films are more inert, because there is more stationary phase shielding the column surface from contact with solutes; using thicker liquid film chromatographic columns can often reduce the peak tailing of active compounds. Chromatographic columns with relatively thick liquid films have higher column capacities. A.2 Packed Chromatographic Columns A.2.1 Packed column fixative coating Dissolve the fixative in the solvent to make it a homogeneous phase solution and soak the carrier in the solution (if necessary, heat to reflux). Gently stir or shake it to avoid crushing the carrier. Place it in a fume hood and evaporate and dry the solvent under infrared light. The mass fraction (w) of the fixative is calculated in accordance with Formula (A.1): Where, m1---the mass of the fixative, expressed in (g); m2---the mass of the carrier, expressed in (g). A.2.2 Empty column pre-treatment Firstly, remove mechanical impurities in the column, use 10% (mass fraction) nitric acid solution to wash it, and use water to wash it, until it becomes neutral. Then, use sodium hydroxide solution (100 g/L) to wash it, and finally, use water to wash it, until it becomes neutral, and dry it. A.2.3 Chromatographic column packing ......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.