GB/T 40062-2021 PDF English

GB/T40062-2021 (GBT40062-2021): PDF in English

GB/T 40062-2021 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 75.160.20 E 31 Method for determination of total inorganic chloride in denatured fuel ethanol and fuel ethanol - Ion chromatography ISSUED ON: APRIL 30, 2021 IMPLEMENTED ON: NOVEMBER 01, 2021 Issued by: State Administration for Market Regulation; Standardization Administration of the People’s Republic of China. Table of Contents Foreword ... 3  1 Scope ... 4  2 Normative references ... 4  3 Terms and definitions ... 4  4 Principle ... 5  5 Reagents and materials ... 5  6 Instruments and apparatuses ... 6  7 Analysis steps ... 7  8 Calculation ... 8  9 Description of the analysis result ... 9  10 Accuracy (95% confidence level) ... 9  11 Quality assurance and control ... 10  Method for determination of total inorganic chloride in denatured fuel ethanol and fuel ethanol - Ion chromatography 1 Scope This Standard specifies the ion chromatography for the determination of total inorganic chlorine content in denatured fuel ethanol and fuel ethanol, including reagents and materials, instruments and apparatuses, analysis procedures, calculations, expression of analysis results, accuracy (95% confidence level) and quality assurance and control. This Standard applies to the determination of total inorganic chloride ion content in denatured fuel ethanol and fuel ethanol. Note: The determination content range of total inorganic chloride ions in this Standard is 0.08 mg/L ~ 10.0 mg/L; the detection-limit is 0.02 mg/L. 2 Normative references The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document. GB/T 6682, Water for analytical laboratory use - Specification and test methods GB/T 8170, Rules of rounding off for numerical values & expression and judgment of limiting values 3 Terms and definitions The following terms and definitions are applicable to this document. 3.1 Denatured fuel ethanol The fuel ethanol that is used to prepare ethanol-added gasoline for vehicles, after adding denaturant. b) Chloride ion standard stock solution B (100 mg/L): accurately pipette 10.0 mL of chloride ion standard stock solution A; place it in a 100 mL volumetric flask; use water to fix volume; mix well. 5.7 Sodium carbonate/sodium hydrogen carbonate eluent: prepare the mixed solution of 4.5 mmol/L sodium carbonate and 1.4 mmol/L sodium hydrogen carbonate as follows: a) Before use, burn sodium carbonate (5.3) at 270 °C ~ 300 °C to constant weight; weigh 47.70 g of sodium carbonate and 11.76 g of sodium hydrogen carbonate (5.4); dissolve in water and place in a 100 mL volumetric flask; use water to fix volume; prepare to obtain a mixed solution of 4.5 mol/L sodium carbonate and 1.4 mol/L sodium hydrogen carbonate, as a sodium carbonate/sodium hydrogen carbonate stock solution; seal and store in the refrigerator freezer at 4 °C. The validity period is not more than 3 months; b) Before use, accurately transfer 2.0 mL of the above sodium carbonate/sodium hydrogen carbonate stock solution; place it in a 2 L volumetric flask; use water to fix volume; mix well; prepare the sodium carbonate/sodium hydrogen carbonate eluent. 6 Instruments and apparatuses 6.1 Ion chromatograph, including: -- Chromatographic column: anion exchange separation column and anion protection column; -- Sample injection device: including six-way valve, sample quantitative loop and injector; -- Suppressor: anion automatic electrolysis regenerative membrane suppressor or other equivalent suppressors; -- Conductivity detector: for temperature compensation or automatic range adjustment; -- Chromatography data system. 6.2 Analytical balance: the sensitivity is 0.000 1g. 6.3 Oven. 6.4 Desiccator. 6.5 Nitrogen-blowing instrument. Where: c -- content of chloride ions in the sample, in milligrams per liter (mg/L); A -- peak area (or peak height) of chloride ions in the sample; A0 -- peak area (or peak height) of the test blank; a -- intercept of the regression equation; b -- slope of the regression equation; f -- dilution factor of the sample. 9 Description of the analysis result For any sample, use the arithmetic average of two repeated measurement results to report the analysis results; round the results to one decimal place according to the provisions of GB/T 8170. 10 Accuracy (95% confidence level) Repeatability: In the same laboratory, when the same analyst uses the same instrument, under the same operating parameters, with standard and accurate operations, to repeatedly measure the same sample, the difference between the two results shall not exceed the value in Table 2. Reproducibility: When the same determination is performed by different analysts in different laboratories, the difference between the two independent determination results obtained shall not exceed the value in Table 2. Table 2 -- Repeatability and reproducibility .......
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