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GB/T 9722-2023 PDF English (GB/T 9722-2006: Older version)Search result: GB/T 9722-2023 (GB/T 9722-2006 Older version)
GB/T9722-2023 (GBT9722-2023): PDF in EnglishGB/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 ri,s is calculated in accordance with Formula (1): Where, tR(i)---the adjusted retention time of each component, expressed in (min); tR(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); Ai---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.......Source: https://www.ChineseStandard.net/PDF.aspx/GBT9722-2023 |