Edible soda ash national standard text

Food additive sodium carbonate National Standard of the People's Republic of China National Standard of the People's Republic of China GB 1886-92 Food additive sodium carbonate instead of GB 1886-83 Food additive Sodium carbonate GB 8920-88 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1 Subject content and scope of application This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of the food additive sodium carbonate. This standard applies to the food additive sodium carbonate produced by the ammonia-alkali method and the combined alkali method using industrial salt as raw material. Molecular formula: Na2CO3 relative molecular mass: 105.99 (according to the 1989 international relative atomic mass) 2 Reference standards GB 601 Preparation of standard solutions for titration analysis of chemical reagents (volume analysis) GB 602 Preparation of standard solutions for determination of impurities in chemical reagents GB 603 Preparation of preparations and products used in chemical reagent test methods GB 3049 General method for determination of iron content in chemical products Phenanthrene (orro)line spectrophotometry GB 3050 General method for determination of chloride content in inorganic chemical products Potentiometric titration method GB 3051 General method for determination of chloride content in inorganic chemical products Mercury method GB 4456 Polyethylene blown film for packaging GB 4857.3 Basic test stacking test method for transport packages GB 4857.5 Basic test vertical impact drop test method for transport packages GB 6678 General principles for sampling of chemical products GB 6682 Laboratory water specifications GB 8450 Determination of arsenic in food additives Arsenic spot method GB 8946 Plastic woven bag GB 8947 Composite plastic woven bag 3 Technical requirements 3.1 Appearance: White powdery crystal. 3.2 Food additive sodium carbonate should comply with the requirements in the table below. ━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━ Project┃ Indicators━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Total alkali content (calculated as Na2CO3), % ≥ ┃ 99.2 ━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Chloride (calculated as NaCl) content, % ≤ ┃ 0.70 ━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Iron (calculated as Fe) content, % ≤ ┃ 0.0040 ━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Heavy metal (calculated as Pb) content, % ≤ ┃ 0.001 ━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Arsenic (calculated as As) content, % ≤ ┃ 0.0002 ━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Loss on ignition * 1),% ≤ ┃ 0.80 ━━━━━━━━━━━━━━━━━━━╋━━━━━━━━━━━━━━━━━━ Water-insoluble matter content, % ≤ ┃ 0.040 Note: 1) Inspection results during packaging. 4 Test methods The reagents and water used in this standard refer to analytically pure reagents and grade three water specified in GB 6682, unless other requirements are specified. The standard solutions, impurity standard solutions, preparations and products required in the test shall be prepared in accordance with the provisions of GB 601, GB 602 and GB 603 unless other regulations are specified. 4.1 Identification 4.1.1 Reagents and materials 4.1.1.1 Hydrochloric acid (GB 622) ； 4.1.1.2 Magnesium sulfate (GB 671): 120g/L solution ； 4.1.1.3 Calcium oxide (GB 1262): Saturated solution at room temperature. Weigh about 3g of calcium oxide, accurate to 0.1g, place it in a reagent bottle, add 1000mL of water, cap the bottle, shake vigorously, and leave to clarify. Take the supernatant when using. 4.1.2 Identification method 4.1.2.1 Preparation of test solution: Weigh 20g of sample, accurate to 0.1g, place it in a beaker, add 100mL of water and let it dissolve. 4.1.2.2 Wet the platinum wire ring with hydrochloric acid and burn it on the flame until it is colorless. Then dip a little test solution and burn it on the flame. The flame will turn bright yellow. 4.1.2.3 When hydrochloric acid is added dropwise to the test solution, carbon dioxide gas is released, and when it is passed into the saturated calcium oxide solution, a white turbid liquid appears. 4.1.2.4 Add magnesium sulfate solution dropwise to the test solution to form a white precipitate. 4.2 Determination of total alkali content 4.2.1 Method summary Use bromocresol green-methyl red as the indicator solution and titrate with hydrochloric acid standard titration solution. 4.2.2 Reagents and materials 4.2.2.1 Hydrochloric acid (GB 622): c(HCl) is about 1mol/L standard titration solution ； 4.2.2.2 Bromocresol green (HG3━1220)-methyl red (HG3━958) mixed indicator solution. Mix bromocresol green ethanol solution (1g/L) and methyl red ethanol solution (2g/L) in a volume ratio of 3+1 and shake well. 4.2.3 Instruments and equipment General laboratory instruments and equipment. 4.2.3.1 weighing bottle: φ30mm×25mm or porcelain crucible, capacity 30 mL ； 4.2.3.2 Electric oven or high temperature furnace: Can be controlled at 250~270℃. 4.2.4 Analysis step: Weigh 1.7g of the sample in a weighing bottle or porcelain crucible that has been pre-heated to constant weight at 250-270°C, accurate to 0.0002g, place it in an electric oven or high-temperature furnace, and heat to constant weight at 250-270°C. Pour the sample into the Erlenmeyer flask, and then accurately weigh the mass of the weighing flask or porcelain crucible. Dissolve the sample in 50 mL of water, add 10 drops of bromocresol green-methyl red mixed indicator solution, titrate with hydrochloric acid standard titration solution until the solution changes from green to dark red, boil for 2 minutes, cool and continue titration until dark red is the end point. 4.2.5 Expression of analysis results The mass percentage of total alkali (calculated as Na2CO3) x1 is calculated according to formula (1): c·V×0.05300 5.300c·V: c——actual concentration of hydrochloric acid standard titration solution, mol/L ； V——The volume of hydrochloric acid standard titration solution consumed in titration, mL ； m——sample mass, g ； 0.053 00——The mass of sodium carbonate in grams equivalent to 1.00mL hydrochloric acid standard titration solution [c(HCl)=1.000mol/L]. The results obtained should be expressed to one decimal place. 4.2.6 The difference between two parallel measurement results is allowed to be no more than 0.2%, and the arithmetic mean is taken as the measurement result. 4.3 Determination of chloride content 4.3.1 Potentiometric titration method 4.3.1.1 For a summary of methods, see Chapter 2 of GB 3050. 4.3.1.2 Reagents and materials 4.3.1.2 .1 Nitric acid (GB 626): 1+1 solution ； 4.3.1.2 .2 Potassium nitrate (GB 647): Saturated solution at room temperature ； 4.3.1.2 .3 Bromophenol blue (HG3━1224): 1g/L ethanol solution ； 4.3.1.2 .4 Sodium chloride (standard reagent) (GB 1253): c (NaCl) = 0.05mol/L standard titration solution. Weigh 2.9225g of sodium chloride that has been baked to a constant weight at 500 to 600°C, accurate to 0.0002g. Place it in a beaker, add water to dissolve, then transfer it all to a 1000mL volumetric flask, add water to the mark, and shake well. 4.3.1.2 .5 Silver nitrate (GB 670): c(AgNO3) is about 0.05mol/L standard titration solution. Weigh 8.75g of silver nitrate, accurate to 0.01g, dissolve in 1000mL of water, and shake well. Stored in brown bottle. Use a pipette to remove 5 mL of sodium chloride standard titration solution, place it in a 100 mL beaker, add 40 mL of water, put in an electromagnetic stirrer, place the beaker on the electromagnetic stirrer, start the stirrer, add 2 drops of bromophenol blue indicator solution, and add nitric acid solution dropwise until it turns yellow. Insert the measuring electrode and reference electrode into the solution, connect the potentiometer wiring, adjust the zero point of the potentiometer, and record the starting potential value. Titrate with silver nitrate standard titration solution, first add 4.00mL, and then gradually add 0.10mL. Record the total volume and the corresponding potential value E after each addition of the silver nitrate standard titration solution, and calculate the difference ΔE2 between the continuously increasing potential values ​​ΔE1 and ΔE1. △The maximum value of E1 is the end point of the titration, and a potential value E will be recorded after the end point. For the recording format, see Appendix C of GB 3050 (reference document). The volume of silver nitrate standard titration solution consumed in the titration to the end point is calculated according to formula (2): b V=V0＋━━V1……………………(2) B Where: V0——The volume of silver nitrate standard titration solution added before the potential increment value △E1 reaches the maximum value, mL; V1——The volume of the last silver nitrate standard titration solution added before the potential increment value △E1 reaches the maximum value, mL; b——The last positive value of △E1 ； B——The sum of the absolute values ​​of the last positive value and the first negative value of △E2. The actual concentration c of the silver nitrate standard titration solution is calculated according to formula (3): c2·V2 c=━━━━………………………………(3) V where: c2——actual concentration of sodium chloride standard titration solution, mol/L ； V2——The volume of sodium chloride standard titration solution, mL ； V——The volume of silver nitrate standard titration solution consumed in titration, mL. 4.3.1.3 For instruments and equipment, see Chapter 3 of GB 3050. 4.3.1.4 Analysis step: Weigh 1g of sample, accurate to 0.01g, place it in a 100mL beaker, add 40mL of water to dissolve. Follow the steps below 4.3.1.2 .5 steps are carried out, starting from "...put the electromagnetic stirrer" to "recording another potential value E after the end point". But no longer add 4.00mL silver nitrate standard titration solution at one time. Do a blank test at the same time. 4.3.1.5 Expression of analysis results: Chloride (calculated as NaCl) mass percentage x2 is calculated according to formula (4): c·(V-V0)×0.05844 5.844c·(V-V0): c——actual concentration of silver nitrate standard titration solution, mol/L ； V——volume of silver nitrate standard titration solution consumed in titration, mL ； V0 - the volume of silver nitrate standard titration solution consumed in the blank test, mL ； x5——Percentage of loss on ignition measured according to Article 4.7 ； m——sample mass, g ； 0.05844——The mass of sodium chloride in grams equivalent to 1.00mL of silver nitrate standard titration solution [c(AgNO3) = 1.000mol/L]. The results should be expressed to two decimal places. 4.3.1.6 The difference between two parallel measurement results is allowed to be no more than 0.02%, and the arithmetic mean is taken as the measurement result. 4.3.2 Mercury measurement method 4.3.2.1 For a summary of methods, see Chapter 2 of GB 3051. 4.3.2.2 See Chapter 4 of GB 3051 for reagents and materials. 4.3.2.3 For instruments and equipment, see Chapter 3 of GB 3051. 4.3.2.4 Analysis step: Weigh 2g of sample, accurate to 0.01g, place it in an Erlenmeyer flask, add 40mL of water to dissolve, add 2 drops of bromophenol blue indicator solution, dropwise add nitric acid solution (1+1 solution) to neutralize until yellow, then add dropwise sodium hydroxide solution until it turns blue, and then use nitric acid solution (1+7) Solution) until it turns just yellow with 2 to 3 drops in excess, add 1 mL of diphenyl azocarbon hydrazide indicator solution, and titrate with mercury nitrate standard titration solution until the color changes from yellow to purple. A blank test was performed at the same time. Save the waste liquid after titration and handle it according to Appendix D of GB 3051. 4.3.2.5 Expression of analysis results: Chloride (calculated as NaCl) mass percentage x3 is calculated according to formula (5): c·(V-V0)×0.05844 5.844c·(V-V0) x3=━━━━━━━━━━━×100=━━━━━━━━━ ………………(5) m(1-x5) m(1-x5) Where: c——actual concentration of mercury nitrate standard titration solution, mol/L ； V——volume of mercury nitrate standard titration solution consumed in titration, mL ； V0——volume of mercury nitrate standard titration solution consumed in blank test titration, mL ； x5——Percentage of loss on ignition measured according to Article 4.7 ； m——sample mass, g ； 0.05844——with 1.00mL mercury nitrate standard titration solution {c〔━━ Hg(NO3)2·H2O〕=1.000mol/L}

Reply 1# lxp69885 Quality and technical indicators of edible soda ash: GB1886--1992 Project indicators Total alkali content (based on the mass fraction of Na2CO3 on a dry basis) % ≥ 99.2 Sodium chloride (based on the mass fraction of NaCl on a dry basis) % ≤ 0.7 Mass fraction of iron (Fe) (on a dry basis) % ≤ 0.004 Heavy metal (based on Pb) content, % ≤ 0.001 Arsenic (based on As) content, % ≤ 0.000 2 Loss on ignition1), % ≤ 0.8 Water-insoluble matter % ≤ 0.03 Packing specifications Light soda ash (kg/bag) Heavy soda ash (kg/bag) Remarks 25 Packed in composite plastic woven bags, flexible container bags or bulk 40 50 750 1000 Bulk Can the above content be referred to

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