GB 34456-2017Feed additive-Sodium dihydrogen phosphate (English PDF)

2.0 Sulfate (SO42-) /% <= 2.0

The standard test methods used reagents and water, did not indicate when the other requirements, refer to analytical reagents and GB/T 6682 provisions Three water.

4.1 Sensory test Visual and odor test products appearance and smell.

4.2.1 Reagents and materials

4.2.1.1 Glacial acetic acid.

4.2.1.2 ammonia solution. Ammonia water = 23.

4.2.1.3 nitric acid solution. Nitric acid water = 18.

4.2.1.4 silver nitrate solution (17g/L). Weigh 1.7g of silver nitrate, dissolved in 100mL water.

4.2.2 Analysis steps

4.2.2.1 Identification of phosphate Weigh the sample 1.0g, dissolved in 20mL water, add silver nitrate solution (4.2.1.4), a yellow precipitate, the precipitate dissolved in excess ammonia dissolved Liquid (4.2.1.2) or nitric acid solution (4.2.1.3), insoluble in glacial acetic acid (4.2.1.1).

4.2.2.2 Identification of sodium ions Weigh the sample 1.0g, add 20mL water to dissolve. Dipped hydrochloric acid with platinum wire ring, the flame burning to colorless. Then dip the test solution on fire Burning flame, the flame should be bright yellow.

4.3 Determination of sodium dihydrogen phosphate

4.3.1 Principle In acidic medium, with Quimociac as precipitating agent, all the phosphate in the sample solution forms quinoline phosphomolybdate to precipitate, Filter, drying, weighing, calculation of sodium dihydrogen phosphate content.

4.3.2 Reagents and materials

4.3.2.1 Sodium molybdate.

4.3.2.2 Citric acid.

4.3.2.3 nitric acid solution. Nitric acid water = 1 1

4.3.2.4 Quinoline.

4.3.2.5 Acetone.

4.3.2.6 Quimociac solution Weigh 70g sodium molybdate (4.3.2.1) was dissolved in 100mL water (solution a); Weigh 60g citric acid (4.3.2.2) was dissolved in 150mL Water and 85 mL of nitric acid solution (solution b); solution a was poured into solution b with stirring (solution c); in 100 mL of water Add 35mL nitric acid solution (4.3.2.3) and 5mL quinoline (4.3.2.4) (solution d); the solution d into solution c, after 12h, Filtration with glass sand crucible, then add 280mL acetone (4.3.2.5), diluted with water to 1000mL, mix. Store in polyethylene bottle.

4.3.3 Instruments and Equipment

4.3.3.1 glass sand crucible Pore size 5µm ~ 15µm.

4.3.3.2 electric oven temperature.

4.3.4 Analysis steps

4.3.4.1 Preparation of test solution Weigh 1g (accurate to 0.0001g) of the sample dried at 105 ° C for 4h, placed in a 100mL beaker, dissolved in 50mL of water, Into a 250mL volumetric flask, water to volume, shake.

4.3.4.2 Preparation of blank test solution In addition to not adding the sample, the amount of other reagents added and the preparation of the test solution exactly the same, and the same sample with the same treatment.

4.3.4.3 Determination Pipette pipette 10mL test solution (4.3.4.1) and blank test solution (4.3.4.2) were placed in 250mL beaker, add water To a total volume of about 100mL, add 50mL Quimociac solution (4.3.2.6), cover the surface dish, in a 75 °C ± 5 °C water bath heat insulation 30s (During the process of adding reagent and heating, no open flame or stirring shall be allowed to avoid agglomeration). Cool to room temperature during cooling Stirring three times to four times, with a pre-weighed 180 ± 5 °C or 250 °C ± 10 °C constant weight glass sand crucible sucked the supernatant by decantation Wash the sediment with a bottle washing 5 times to 6 times, each time about 20mL of water, and finally the precipitate was transferred to a glass sand crucible, the precipitate washed with water 3 times ~ 4 times. The glass sand crucible with the precipitate placed in an electric oven, dried at 180 °C ± 5 °C 45min or 250 °C ± 10 °C Under the dry 15min. Remove, placed in a desiccator cooled to room temperature, weighed, accurate to 0.0001g.

4.3.5 Calculation and representation of results Sodium dihydrogen phosphate content of sodium dihydrogen phosphate (NaH2PO4) mass fraction w1, the value is expressed in%, according to equation (1) calculation. w1 = (m1-m2) × 0.0542 m × (10/250) × 100% (1) In the formula. m1

--- test solution generated quinoline phosphomolybdate precipitation quality, in grams (g); m2

--- blank test solution generated quinoline phosphomolybdate precipitation quality, in grams (g); 0.0542

--- quinoline phosphomolybdate conversion coefficient of sodium dihydrogen phosphate; m

--- the quality of the sample, in grams (g). Sodium dihydrogen phosphate to total phosphorus (P) mass fraction w2 dollars, the value is expressed in%, according to equation (2) Calculate. w2 = 0.2583 × w1 (2) In the formula. 0.2583

--- sodium dihydrogen phosphate conversion coefficient of phosphorus; w1

--- sodium dihydrogen phosphate content of sodium dihydrogen phosphate (NaH2PO4) mass fraction. The absolute difference between two parallel determination results is not more than 0.3%, the arithmetic mean of two parallel determination results is the determination result, and the result Keep one after the decimal point.

4.4 Determination of fluorine content Weigh the sample 1g ~ 2g (accurate to 0.0001g), placed in 100mL volumetric flask, add 1mol/L hydrochloric acid solution and set to volume Graduation, mixing, dry filtration (discard the first 20mL filtrate), the filtrate was collected. Take 25mL filtrate to 50mL volumetric flask, the remaining steps by GB/T 13083-2002 Determination.

4.5 Determination of arsenic According to GB/T 13079-2006 Chapter

5 Determination.

4.6 Determination of lead content According to GB/T 13080 determination.

4.7 Determination of chromium content According to GB/T 13088 determination.

4.8 Determination of water insoluble content According to GB 25564-2010 Appendix A A.5 Determination of the method.

4.9 pH measurement According to GB 25564-2010 Appendix A. Determination of A.10 method.

4.10 Determination of loss on drying According to GB/T 6435 determination.

4.11.1 Reagents and materials

4.11.1.1 hydrochloric acid solution. Hydrochloric acid = 1 1.

4.11.1.2 barium chloride solution (122g/L). Weigh 12.2g barium chloride, 100mL water was dissolved.

4.11.1.3 silver nitrate solution (17g/L). Weigh 1.7g silver nitrate, 100mL water was dissolved.

4.11.2 Instruments and Equipment

4.11.2.1 glass sand crucible with a diameter of 5µm ~ 15µm.

4.11.2.2 water bath.

4.11.2.3 electric oven temperature.

4.11.3 Analysis steps Weigh the sample 1g ~ 2g (accurate to 0.0001g), add 10mL hydrochloric acid solution (4.11.1.1) heated to dissolve, set the volume of 250mL Volumetric flask, filtered with slow filter paper (qualitative). Precision drawing 20.0mL filtrate, placed in 250mL beaker. Add two drops of methyl orange indicator solution, Hydrochloric acid solution (4.11.1.1) was added dropwise in red with an excess of 2 mL and water was added to bring the total volume to.200 mL. Boil 5min, add slowly with stirring 10mL hot (about 80 ° C) barium chloride solution (4.11.1.2) was placed in a (80 ± 5) ° C water bath for 2h. Cool to room temperature and use at (105 ± 2) °C constant weight glass sand crucible filter. Wash the precipitate with water until there is no chloride in the filtrate (test method Liquid, add 5mL silver nitrate solution (4.11.1.3) mix, place 5min does not appear cloudy). The glass sand crucible and precipitation (105 ± 2) °C Dry to constant weight, weighing.

4.11.4 Calculation and representation of results Sulfate content (in SO2-4 meter) mass fraction w3 meter, the value is expressed in%, according to equation (3) calculation. w3 = (m1-m2) × 0.4116 m × (V1/V2) × 100% (3) In the formula. m1

--- glass sand crucible and precipitation quality, in grams (g); m2

--- glass sand crucible quality, in grams (g); 0.4116

--- Barium sulfate precipitation conversion coefficient of SO2-4; m

--- the quality of the sample in grams (g); V1

--- take the volume of the sample decomposition liquid in milliliters (mL); V2

--- sample decomposition liquid volume, in milliliters (mL). The absolute difference between two parallel determination results is not more than 0.3%, the arithmetic mean of two parallel determination results is the determination result, and the result Keep one after the decimal point.

5 inspection rules

5.1 group approved The same material, the same production process, continuous production or the same shift production of a batch of products, but each batch of products shall not exceed 10t.

5.2 Sampling According to the provisions of GB/T 14699.1 sampling.