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GB 1886.350-2021 PDF in English


GB 1886.350-2021 (GB1886.350-2021) PDF English
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GB 1886.350-2021: PDF in English

GB 1886.350-2021 GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA National Food Safety Standard - Food Additives - Nitrous Oxide ISSUED ON: SEPTEMBER 07, 2021 IMPLEMENTED ON: MARCH 07, 2022 Issued by: National Health Commission; State Administration for Market Regulation. Table of Contents 1 Scope ... 3  2 Chemical name, molecular formula, structural formula and relative molecular mass ... 3  3 Technical requirements ... 3  Annex A Inspection methods ... 5  National Food Safety Standard - Food Additives - Nitrous Oxide 1 Scope This Standard applies to nitrous oxide, a food additive obtained by thermal decomposition using ammonium nitrate as a raw material. 2 Chemical name, molecular formula, structural formula and relative molecular mass 2.1 Chemical name Nitrous oxide (nitrous oxide). 2.2 Molecular formula N2O 2.3 Structural formula N-N-O 2.4 Relative molecular mass 44.01 (according to 2018 international relative atomic mass) 3 Technical requirements 3.1 Sensory requirements Sensory requirements shall meet the requirements of Table 1. Annex A Inspection methods WARNING: Some procedures specified in the test method may lead to dangerous situations. The operator shall take appropriate safety and protective measures. During the test, there shall be nitrous oxide tail gas treatment measures. A.1 General The reagents and water used in this Standard refer to analytically-pure reagents and grade 3 water specified in GB/T 6682 when other requirements are not indicated. The solution used in the test refers to an aqueous solution when it is not specified which solvent is used to prepare it. A.2 Identification test A.2.1 Method principle Nitrous oxide can make red wood sticks ignite and burn. But when it passes into alkaline pyrogallic acid solution, the solution will not turn brown. A.2.2 Reagents and materials A.2.2.1 Wooden sticks. A.2.2.2 Pyrogallic acid (1,2,3-pyrogallol). A.2.2.3 Potassium hydroxide. A.2.2.4 Alkaline pyrogallic acid solution: Take 0.5g of pyrogallic acid (1,2,3- pyrogallol). Add 2mL of water to dissolve. Shake well to obtain solution A. Take 12g of potassium hydroxide. Add 8mL of water to dissolve. Shake well to obtain solution B (saturated potassium hydroxide solution). Mix the two solutions A and B immediately before use. It shall be prepared in a vacuum glove box. A.2.3 Instruments and equipment Vacuum glove box. A.2.4 Analysis steps A.2.4.1 Connect the sample gas to the gas pressure reducing valve. Open the valve. Pour gas into a clean reagent bottle. Close the gas sampling valve. Quickly cover the reagent bottle with a watch glass. Then put the red wood sticks into the reagent bottle containing nitrous oxide gas. Wooden sticks can A.5.2 Reagents and materials A.5.2.1 Chromatographic carrier gas: High-purity helium gas, whose purity should be greater than 99.999%. A.5.2.2 Standard sample: Use helium with a purity greater than 99.9999% as the bottom gas. The oxygen content (volume fraction) is 0.2%, and the nitrogen content (volume fraction) is 0.8%. A.5.3 Instruments and equipment Gas chromatograph: Equipped with thermal conductivity detector. A.5.4 Reference chromatographic conditions A.5.4.1 Chromatographic column: Stainless steel tube with a length of about 1.5m and an inner diameter of 2mm, with a 13X molecular sieve with a particle size of 0.25mm~0.4mm, or other equivalent chromatographic columns. A.5.4.2 Carrier gas flow (He>99.999%): 10mL/min. A.5.4.3 Detector temperature: 160°C. A.5.4.4 Oven temperature: 30°C. A.5.4.5 Makeup gas flow rate: 5.0mL/min. A.5.5 Determination steps A.5.5.1 Preparation Turn on the instrument according to the instrument manual. Set various operating parameters of the instrument until the instrument works normally. A.5.5.2 Calibration Connect the standard sample to the instrument through the sampling tube. Turn on the sample to fully purge the sampling system until a representative sample is obtained. Switch the sampling valve to inject samples into the instrument. Measure the response value of the instrument (peak area or peak height). Repeat the injection at least 2 times, until the relative deviation of the response value is less than 5%. Take the average value As. A.5.5.3 Determination Perform under exactly the same conditions as the calibration. Connect the sample gas to the instrument through the sampling tube. Turn on the sample to fully purge the sampling system until a representative sample is obtained. Switch the sampling valve to inject samples into the instrument. Measure the A.7 Determination of ammonia A.7.1 Method principle When a certain amount of gas passes through the detection tube, the measured gas in the gas sample is adsorbed on the surface of the indicator powder by diffusion and chemically reacts with the color-generating chemical reagents to cause the indicator powder to change color. The concentration of the measured gas in the gas is different. The length of the color-changing column is also different. A.7.2 Reagents and materials Ammonia detection tube: The volume fraction of the measuring range is 1×10- 6~30×10-6, or other suitable measuring ranges. A.7.3 Analysis steps The measurement starts when the nitrous oxide gas is injected into the detection tube. The control of injection volume, injection flow and color change are carried out in accordance with the operating instructions of the detection tube. According to the length of the color change of the detection tube, the ammonia content is obtained. A.8 Determination of nitric oxide and nitrogen dioxide A.8.1 Test tube method A.8.1.1 Method principle When a certain amount of gas passes through the detection tube, the measured gas in the gas sample is adsorbed on the surface of the indicator powder by diffusion and chemically reacts with the color-generating chemical reagents to cause the indicator powder to change color. The concentration of the measured gas in the gas is different. The length of the color-changing column is also different. A.8.1.2 Instruments and equipment Nitrogen oxide detection tube: Volume fraction of the measuring range is 0.2×10-6~5×10-6, or other suitable measuring ranges. A.8.1.3 Analysis steps The measurement starts when the nitrous oxide gas is injected into the detection tube. The control of injection volume, injection flow and color change are carried out in accordance with the operating instructions of the detection tube. According to the length of the color change of the detection tube, the total ......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.