Some standard content:
Standard chemical reagent of the Ministry of Chemical Industry of the People's Republic of China
Diammonium hydrogen citrate
This reagent is a white crystalline powder, easily soluble in water. Molecular formula: C.Hi,O,N2
Structural formula:
COONH4
Molecular weight: 226.18 (according to the international atomic weight in 1979) 1 Technical requirements
1. 1 CHO,N2 content not less than:
Analytical pure
Chemical pure
1.2 Maximum impurity content (indicators in percentage): Name
Clarity test
Water insoluble matter
Ignition residue (in terms of sulfate)
Chloride (CI)
Sulfur compounds (in terms of SO) Phosphorus compounds (in PO,) Oxalate (C,04) Calcium (Ca) Iron (Fe) Heavy metals (in Pb) COONH4 Ministry of Chemical Industry of the People's Republic of China 1982-01-28 1292 HG 3-1465-82 Replace HGB 3294--60
1982-12-01Implementation
2Test method
HG3-—1465—-82
The standard solution, impurity standard solution, preparation and product in the determination shall be prepared in accordance with the provisions of GB60177 "Standard Solution Preparation Method", GB602-77 "Impurity Standard Solution Preparation Method" and GB603-77 "Preparation Method of Preparation and Product". 2.1C.HO, N2 content determination: Weigh 1g sample to 0.0002g. Dissolve in 40ml water without carbon dioxide, add 10ml neutral formaldehyde, 2 drops of 1% phenolphthalein indicator solution, and titrate with 0.5N sodium hydroxide standard solution until the solution turns pink. The percentage content (X) of C, HO, N2 is calculated as follows: y.cx0.07539×100
wherein -- the amount of sodium hydroxide standard solution, ml; c—
the equivalent concentration of sodium hydroxide standard solution, N; G- the weight of the sample, g;
0.07539—the number of grams of CHu4O, N2 per milligram equivalent. 2.2 Impurity determination: The sample must be weighed to 0.01g. G
2.2.1 Clarity test: Weigh 20g sample and dissolve it in 100ml water. Its turbidity shall not be greater than the clarity standard (refer to HG3-1168-78 "Preparation and determination method of clarity standard": analytical pure
chemical pure
No. 4;
No. 6.
2.2.2 Water insoluble matter: Keep the solution for clarity test in a water bath for 1h, filter it with a constant weight No. 4 glass filter, wash the filter residue with hot water until there is no ammonium ion reaction in the washing solution, and bake it at 105-110°C to constant weight. The weight of the filter residue shall not be greater than: analytical pure
chemical pure
2.2 .3 Burning residue: Weigh 10g of sample, place in a constant weight crucible, heat to carbonize, and cool. Add 1ml of sulfuric acid, heat until sulfuric acid vapor escapes, and burn to constant weight at 800℃. The weight of the residue shall not be greater than: analytical grade,
chemically pure
2.2.4 Chloride: Measure 10ml of solution 1, neutralize with 5N nitric acid, dilute to 25ml, add 2ml5N nitric acid, 1ml0.1N silver nitrate, shake the hook, and let it stand for 10rmin. The turbidity shall not be greater than the standard. The standard is to take the following amount of chloride impurity standard solution: analytical grade...
chemically purewwW.bzxz.Net
and treat it in the same way as the neutralized sample solution. 0 .01mgCl;
0.02mgCl.
Note: Preparation of solution 1 Weigh 5g of sample, place in golden blood (or platinum blood), add 5ml of 5% anhydrous sodium carbonate solution, evaporate on a water bath, heat to carbonize, gradually increase the temperature to 700℃ and burn until white. If the residue does not turn white, moisten it with a small amount of water, evaporate to dryness on a water bath, and repeat this operation until the residue turns completely white, then cool. Dissolve the residue in water, filter, wash, combine the filtrate and washings, and dilute to 50ml. 2.2.5 Sulfur compounds: Measure 5ml of solution I, add 1ml of hydrogen peroxide, boil until the hydrogen peroxide decomposes, neutralize with 3N hydrochloric acid, and dilute to 10ml. Add 5m 195% ethanol, 1ml 3N hydrochloric acid, add 3ml 25% barium chloride solution under continuous shaking, dilute to 25ml, shake well, and let stand for 10 minutes. The turbidity shall not be greater than the standard. The standard is to take the following amounts of sulfate impurity standard solution: analytical pure
chemical pure
0.025mgsO4;
0.050mgSO4.
and 5ml sample solution are treated in the same way at the same time.
2.2.6 Phosphorus compounds: Measure 5ml solution 1, add 10ml water and 2 drops of 30% hydrogen peroxide, heat to boiling, evaporate to dryness on a water bath, and cool. Residual 1293
HG 3-1465--82
Dissolve the residue in water and dilute to 10ml. Add 2 drops of saturated 2,4-dinitrophenol indicator solution, neutralize with 4N sulfuric acid until the yellow color disappears, and dilute to 20ml. Add 6ml 4N sulfuric acid and cool. Add 4ml 10% ammonium molybdate solution, shake well, and let stand for 10min. Add 4ml 10% tartaric acid solution and 2ml 1% ascorbic acid solution, dilute to 40ml, add 0.4ml of freshly prepared 0.5% stannous chloride solution, dilute to 50ml, and shake well. The blue color should not be darker than the standard.
The standard is to take the following amount of phosphate impurity standard solution: analytical pure
chemical pure·
and 5ml sample solution I and treat it in the same way. 0.010mgPO4
0.025mgPO4.
2.2.7 Oxalate: Weigh 5g sample, dissolve in 25ml water (filter if necessary), add 3ml acetic acid, 10ml 95% ethanol, and divide the solution into two equal parts. Add 1ml 10% calcium acetate solution to one part, shake well, and let stand for 1h. There should be no difference in transparency between the two. 2.2.8 Calcium: Atomic absorption spectrophotometry. Instrument conditions
Light source: calcium hollow cathode lamp;
Wavelength: 422.7nm;
Flame: acetylene-air.
Determination method: Weigh 10g sample, dissolve in water, and dilute to 100ml. Take 20ml, a total of four parts. Determine according to the provisions of Chapter 2, Article 2, Paragraph (2) of HG3-1013-76 "General Rules for Atomic Absorption Spectrophotometry". 2.2.9 Iron: Weigh 1g sample, dissolve in water, and dilute to 25ml. Add 1ml hydrochloric acid, 30mg ammonium persulfate and 2ml 25% ammonium thiocyanate solution, extract with 10ml n-butanol, the red color of the organic layer shall not be darker than the standard. The standard is to take the following amount of iron impurity standard solution: analytical pure
chemical pure
and treat it in the same way as the sample.
0.005mgFe;
0.020mgFe.
2.2.10 Heavy metals: Weigh 4g sample, dissolve in water, neutralize with 10% sodium hydroxide solution (about 6ml), and add 2ml in excess, dilute to 40ml. Take 30ml, dilute to 45ml, add 1ml 20% potassium sodium tartrate solution, 2ml 5% thioacetamide solution and 2ml 10% sodium hydroxide solution, shake well, and let it stand for 10min. The dark color shall not be darker than the standard. The standard is to take the remaining 10ml sample solution and the following amount of lead impurity standard solution: analytical pure ·
chemical pure
dilute to 45ml, and treat it in the same way as the sample solution of the same volume. 3 Inspection rules
Sampling and acceptance shall be carried out in accordance with the provisions of GB619-77 "Sampling and Acceptance Rules". 4 Packaging and marking
4.1 Packaging
According to the provisions of HG3--119--64 "Chemical Reagent Packaging and Marking". Inner packaging form: Gz-2, Gz-2; G-3.Gz-3; Outer packaging form: I1, 1;
Packing unit: Class 4, 5.
4.2 Marking
According to the provisions of HG3119--64.
·0.01mgPb;
0.02mgPb.
Additional Notes:
HG 3—1465—8
This standard was proposed by the Sichuan Provincial Chemical Industry Bureau and is under the jurisdiction of Beijing Chemical Reagent General Administration. This standard was drafted by Chengdu Chemical Reagent Factory. The main drafter of this standard was Chen Junru.
This standard was first issued in 1960.
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