GB 1886.46-2015National Food Safety Standard -- Food Additives -- Sodium hydrosulfite (English PDF)

2.2 Relative molecular mass

174.11 (according to 2007 international relative atomic mass)

3.1 Sensory requirements

Sensory requirements shall comply with the requirements of Table 1.

Table 1 Sensory requirements

Project requires test methods Color White Status crystalline powder Take the right amount of sample is placed in a clean, dry white porcelain dish, in natural light, observe its color and status

3.2 Physical and Chemical Indicators

Physical and chemical indicators should be consistent with the provisions of Table 2.

Table 2. Physical and chemical indicators

Item Index Test Method Hypo, w /% >= 88.0 Appendix A A.4 Edetate disodium, w /% by Appendix A test A.5 Heavy metals (Pb)/(mg/kg) <= 10.0 A.6 in Appendix A Lead (Pb)/(mg/kg) <= 5.0 GB 5009.75 Cadmium (Cd)/(mg/kg) <= 2.0 GB 5009.15 TABLE 2 (cont.) Item Index Test Method Arsenic (As)/(mg/kg) <= 1.0 GB 5009.76 Zinc (Zn), w /% <= 0.03a A.7 Appendix A Clarity through test A.8 in Appendix A Formate (in terms HCHO), w /% <= 0.05b A.9 in Appendix A a sodium formate process production of food additives hypo indicator does not control the content of zinc.

b In zinc process production of food additives hypo formate does not control the content of the index.

Appendix A

Testing method

A.1 Safety Tips

Reagents used in this test method are toxic or corrosive, care should be taken. Such as water splashed on the skin should immediately Flushing, severe cases should be treated immediately.

A.2 General Provisions this standard reagents and water in the absence of other specified requirements, refer to the three water analytical reagent and GB/T 6682 regulations. test the required standard solution, impurity standard solution, preparations and products, did not indicate when the other requirements according to GB/T 601, GB/T 602, GB/T 603 provisions of the preparation. Solution was used in the tests did not indicate what is formulated with solvent, it refers to an aqueous solution.

A.3 Identification Test A.3.1 Reagents and materials A.3.1.1 hydrochloric acid solution. 11.

A.3.1.2 copper sulfate. 50g/L.

A.3.1.3 potassium permanganate solution. 3.5g/L.

A.3.1.4 Antimonite solution. Weigh 2g antimony potassium pyrophosphate, add 100mL water dissolved, boil for about 5min, rapid cooling, 10mL Sodium hydroxide solution, after placing 24h, filtered.

A.3.2 Identification method A.3.2.1 low sulfite identification as follows.

a) Take 10mL10g/L test solution, add 2mL when copper sulfate solution, which was gray and black;

b) Take 10mL10g/L test solution, potassium permanganate solution is added 1mL, the color of the solution disappears.

A.3.2.2 Identification of the sodium salt as follows.

a) Take a platinum wire dipped hydrochloric acid till colorless, remarriage take 10g/L test solution in the alcohol lamp burning yellow;

b) take appropriate 50g/L test solution is added antimony potassium pyrophosphate solution, a white crystalline precipitate (when the test tube with a glass rod friction wall, can accelerate the generation of precipitation).

A.4 Determination of low sodium sulphite A.4.1 Method summary Low sodium sulfite and neutral formaldehyde, generating formaldehyde and sodium bisulfite, sodium formaldehyde sulfoxylate, sodium sulfoxylate formaldehyde and iodine effect, Determine the amount that the consumption of low sodium sulfite standard iodine titration solution.

A.4.2 Reagents and materials A.4.2.1 hydrochloric acid solution. 111.

A.4.2.2 neutral formalin solution. 11. Take formaldehyde solution 100mL and 100mL water, placed in 400mL beaker, stir, add A few drops of 10g/L phenolphthalein indicator solution, sodium hydroxide solution with 100g L/and to the solution was slightly red and then hydrochloric acid solution was adjusted to reddish Just fade.

A.4.2.3 soluble starch solution. 10g/L.

A.4.2.4 standard iodine titration solution. c 12I2 ÷ ~0.1mol/L.

A.4.3 Analysis step

Weigh 1g sample, accurate to 0.0002g, placed in a pre beaker 20mL neutral formalin solution, stirring until completely dissolved, all transferred to 250mL volumetric flask, dilute to the mark, shake. Pipette 25mL of this solution in 250mL conical flask, add 4mL hydrochloric acid solution, titration with iodine standard solution titration, was added near the end 3mL starch solution and continue titration until the solution was light blue in it does not disappear shall end within 30s. While the same treatment the blank test solution.

A.4.4 Calculation Results Hypo mass fraction w1, according to equation (A.1) Calculated.

V-V0

1000 × c × M

× 100% (A.1)

Where.

V --- volume of iodine standard titration solution consumed titration test solution, in milliliters (mL);

Volume of standard iodine titration V0 --- blank test solution consumed in milliliters (mL);

1000 --- conversion factor;

C --- iodine concentration standard titration solution, expressed in moles per liter (mol/L);

M --- hypo molar mass in grams per mole (g/mol), M 4Na2S2O4 ÷ = 43.53é êê úú;

M --- the quality of the sample, in grams (g);

Pipette 25 --- volume of the test solution, in milliliters (mL of);

The total volume of the test solution --- 250 milliliters (mL).

The results parallel arithmetic mean of the measurement results shall prevail. In two independent determination results obtained under repeatability conditions absolute difference not more than 0.5%.

A.5 Determination of disodium edetate A.5.1 Method summary Arsenite the chromium ion is reduced to chromium ions, chromium ions and ethylenediaminetetraacetic acid disodium generate violet complex that can be used edetate Disodium test.

A.5.2 Reagents and materials A.5.2.1 acetic acid.

A.5.2.2 Potassium chromate solution. 5g/L.

A.5.2.3 sodium hydroxide solution. 25g/L.

A.5.2.4 arsenite solution. 10g/L. Weigh 1g arsenite (arsenic trioxide), sodium hydroxide solution was added 30mL, heated and dissolved.

After cooling, acetic acid was slowly added feature to 100mL.

A.5.3 Analysis step

Weigh 0.50g ± 0.01g sample was placed in a test tube, add 5mL dissolved in water, add 2mL potassium chromate solution, 2mL arsenite solution Was heated in a water bath was purple 2min not qualified.

A.6 heavy metals (Pb) Determination A.6.1 Method summary in weakly acidic solution of heavy metal ions and divalent sulfur ions to form a colored sulfide precipitation, low heavy metal content, generate stable Dark suspensions, for visual colorimetric determination of heavy metals.

A.6.2 Reagents and materials A.6.2.1 hydrochloric acid.

A.6.2.2 acetic acid solution. 119.

A.6.2.3 sodium sulfide solution.

A.6.2.4 Lead standard solution. 1mL solution containing lead (Pb) 0.010mg. Pipette 10.00mL lead standard solution, placed in 100mL flask Diluted with water to the mark. Using now.

A.6.2.5 standard colorimetric solution. Pipette 2.00mL lead standard solution, placed in 50mL colorimetric tube, add 2mL acetic acid solution, and the test Test solution while the same treatment.

A.6.3 Analysis step

A.6.3.1 Preparation of test solution A Weigh 10.00g ± 0.01g sample was placed in 300mL beaker, add water to dissolve 60mL, 10mL hydrochloric acid plus adjustable electric and evaporated to dryness. Carefully heat to strengthen the spontaneous combustion of sulfur. To the residue was added 30mL water and 10mL of hydrochloric acid, and then evaporated to an electric furnace in an adjustable dry. The residue was dissolved in water and diluted with water to about 30mL, filtered and the filtrate and washings were placed in 50mL volumetric flask, dilute with water to Mark and shake. This solution as the test solution A. The solution was measured for the content of heavy metals, determination of lead in dithizone colorimetry, cadmium Determination of the content of the zinc content in colorimetry and visual colorimetry.

A.6.3.2 Determination Pipette Pipette 10mL test solution A, placed in 50mL colorimetric tube, add 2mL acetic acid solution, a solution of 2 drops of sodium sulfide solution Dilution with water to the mark. After standing 5min, the color of the test solution must not be darker than the standard colorimetric solution.

A.7 Determination of zinc (Zn) of A.7.1 atomic absorption spectrophotometry (Arbitration Act) A.7.1.1 Method summary the treated sample, the absorbance was measured in the atomic absorption spectrometer. In a certain concentration range, the zinc content into its absorbance it is proportional.

A.7.1.2 Reagents and materials A.7.1.2.1 hydrochloric acid solution. 14.

A.7.1.2.2 Zinc standard solution. 1mL solution of zinc (Zn) 0.05mg. Pipette 50.00mL zinc standard solution, placed in 100mL capacity Volumetric flask, dilute to the mark, shake. The solution is valid for one month.

A.7.1.2.3 Water. Water line with two GB/T 6682 regulations.

A.7.1.3 instruments and equipment Atomic absorption spectrophotometer.

A.7.1.4 measuring step Drawing A.7.1.4.1 calibration curve Pipette were pipetted 0.00mL, 1.00mL, 2.00mL, 3.00mL standard zinc solution, placed in 4 100mL volumetric flask, 5mL hydrochloric acid solution was added, diluted with water to the mark. Acetylene - air flame, at a wavelength of 213.8nm at the atomic absorption spectrophotometry Photometer adjusted to the best working condition, zero water, absorbance was measured. Subtracting the absorbance of the blank solution from the absorbance of each standard solution Degree in mass of zinc as the horizontal, the vertical axis corresponding to the absorbance, drawing working curve.

A.7.1.4.2 Determination Pipette 5mL test solution B, placed in 100mL flask, add 5mL hydrochloric acid solution, diluted with water to the mark, shake uniform. The following article from the press A.10.1.4.1 "acetylene - air flame, the absorbance is measured from the beginning" to operate. While the same treatment blank test Test solution. Isolated appropriate quality zinc from the working curve.

A.7.1.5 Calculation Results Zinc (Zn) content of w2, according to equation (A.2) Calculated.

m3-m1

100 × 10

× 100% (A.2)

Where.

Numerical test solution of zinc mass m3 --- isolated from the working curve, in micrograms (µg);

Value m1 --- isolated from the working curve blank test solution of zinc mass, in micrograms (µg);

Numerical m2 --- sample mass, expressed in grams (g);

Pipette 5 --- volume of the test solution, in milliliters (mL of);

100 --- Total volume of test solution in milliliters (mL of);

106 --- conversion factor.

The results parallel arithmetic mean of the measurement results shall prevail. In two independent determination results obtained under repeatability conditions absolute difference not more than 0.002%.

A.7.2 visual colorimetry A.7.2.1 Method summary in acidic medium, the zinc ions and potassium ferrocyanide solution, a white precipitate, zinc can be used for visual colorimetric method.

A.7.2.2 Reagents and materials A.7.2.2.1 ammonia solution. 23.

A.7.2.2.2 hydrochloric acid solution. 13.

A.7.2.2.3 potassium ferrocyanide solution. 100g/L. Weigh 10g of potassium ferrocyanide, accurate to 0.01g, diluted with water to 100mL, the solution Was using now.

A.7.2.2.4 Zinc standard solution. 1mL solution containing zinc 0.10mg.

A.7.2.3 analysis step Pipette with a pipette 5mL test solution A, a 50mL beaker was added 0.1mL aqueous ammonia solution, filtered and the filtrate into 25mL colorimetric tube, dilute with water to 20mL, plus 5mL hydrochloric acid solution, shake, add 0.1mL solution of potassium ferrocyanide, placed 15min, Turbidity shall not exceed the standard turbidity solution.

Turbidity standard solution with a pipette Pipette 3.00mL zinc standard solution, placed in 25mL colorimetric tube, dilute with water to 20mL, plus 5mL hydrochloric acid solution, shake, add 0.1mL solution of potassium ferrocyanide, placed 15min, while the same treatment with the test solution.

A.8 Determination of Clarity A.8.1 Method summary the dithionite dissolved in neutral formaldehyde solution, in the case of direct sunlight, and by observing the sodium dithionite solution Insolubles content was determined to clarity.

A.8.2 Reagents and materials A.8.2.1 neutral formalin solution. 11.

A.8.2.2 nitric acid solution. 12.

A.8.2.3 dextrin solution. 20g/L.

A.8.2.4 silver nitrate solution. 20g/L.

A.8.2.5 hydrochloric acid standard solution. c (HCl) ~0.1mol/L.

A.8.2.6 chloride standard solution. 1mL solution of chlorine (Cl) 0.01mg. Pipette chloride standard solution 10.00mL, resting 100mL volumetric flask, dilute to the mark, shake. The solution is using now.

A.8.3 Analysis step

A.8.3.1 Preparation of standard reference solution (slightly cloudy) of Pipette Pipette 6mL chloride standard solution, placed in 25mL colorimetric tube, add water to about 20mL, nitric acid solution is added 1mL Diluent, 0.2mL 1mL dextrin solution and silver nitrate solution with water to the mark. Placed in the case to avoid direct sunlight 15min.

A.8.3.2 Determination Weigh 0.50g ± 0.01g sample was placed in a pre-filled with neutral formaldehyde solution 25mL 10mL colorimetric tube, completely dissolved, with Diluted with water to the mark. Place 5min, in the absence of direct sunlight, observed from the top down, the turbidity of the test solution is not greater than the standard Nephelometric turbidity shown solution.

During the test, it should be controlled standard reference solution and the test solution is placed 15min 5min place simultaneously point comparison.

A.9 Determination of formate (in HCHO basis) A.9.1 Method summary in the medium of hydrochloric acid, magnesium formate will be reduced to formaldehyde, and chromium sour reaction effects occur, it can be used for visual colorimetric formate Determination.

A.9.2 Reagents and materials A.9.2.1 magnesium.

A.9.2.2 sulfuric acid.

A.9.2.3 hydrochloric acid solution. 11.

A.9.2.4 chromotropic acid solution. c (C10H6Na2S2O8 · 2H2O) = 10g/L. Weigh 0.5g chromotropic acid, sulfuric acid plus 50mL shake mix, from Centrifuged, the supernatant use, Extemporaneous.

A.9.2.5 Formaldehyde standard solution. 1mL solution containing formaldehyde 0.002mg. Pipette 2.00mL formaldehyde standard solution (1g/L), placed 1000mL volumetric flask, dilute to the mark, shake. Using now.

A.9.2.6 standard colorimetric solution. Pipette 2.50mL formaldehyde solution was added 5mL hydrochloric acid solution, then add a small amount of magnesium twice, to add about 0.3g, almost no bubbles, the surface covered dish, placed 2h. All were transferred to 50mL colorimetric tube, add 2mL of sulfuric acid, 0.5mL chromotropic acid, heated in boiling water bath for 10min, diluted with water to the mark.

A.9.3 Analysis step

Weigh 0.100g ± 0.001g sample placed in 100mL flask, diluted with water to the mark. Pipette 10mL the solution was placed in a beaker, was added 5mL hydrochloric acid solution, then add a small amount of magnesium twice, adding to about 0.3g, after watching almost no bubbles, Cover the surface of the dish, place 2h. All were transferred to 50mL colorimetric tube, add 2mL of sulfuric acid, 0.5mL chromotropic acid, heated on a boiling water bath After 10min, diluted with water to the mark. Its color can not be deeper than the standard colorimetric solution.

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