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Food Additives Acid Red (azo Indirubin)
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GB 28309-2012
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Basic data | Standard ID | GB 28309-2012 (GB28309-2012) | | Description (Translated English) | Food Additives Acid Red (azo Indirubin) | | Sector / Industry | National Standard | | Classification of Chinese Standard | C54;X40 | | Classification of International Standard | 67.220.20 | | Word Count Estimation | 19,179 | | Regulation (derived from) | Ministry of Health Bulletin No. 7 of 2012 | | Issuing agency(ies) | Ministry of Health of the People's Republic of China | | Summary | This Chinese standard applies to 1-naphthylamine-4 sulfonate by diazotization with a 1-naphthylamine-4 Sodium coupling obtained food additives Acid Red (Azo Rubine). | GB 28309-2012: Food Additives Acid Red (azo Indirubin)---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Food Additives Acid Red (azo Indirubin)
National Standards of People's Republic of China
National standards for food safety
Food Additives Acid Red (Azo-Red)
2012-04-25 release
2012-06-25 Implementation
Issued by the Ministry of Health of the People's Republic of China
National standards for food safety
Food Additives Acid Red (Azo-Red)
1 Scope
This standard applies to 1-naphthylamine-4-sulfonic acid sodium diazotization and 1-naphthol-4-sulfonate coupling and the preparation of food additives acid red (even
Nitrogen jade red).
2 Chemical name, structural formula, molecular formula and relative molecular mass
2.1 Chemical name
1-hydroxy-2- (4-azo naphthalenesulfonic acid) -4-naphthalenesulfonic acid disodium salt
2.2 Structural formula
2.3 Molecular formula
C20H12N2Na2O7S2
2.4 Relative molecular mass
502.43 (according to the.2007 International Relative Atomic Quality)
3 technical requirements
3.1 sensory requirements. should be consistent with the provisions of Table 1.
Table 1 sensory requirements
The project requires a test method
Color reddish brown to dark reddish brown
State powder or particles
Take the appropriate amount of sample placed in a clean, dry white porcelain dish, in the natural light,
Observe its color and state
3.2 Physical and chemical indicators. should be consistent with the provisions of Table 2.
Table 2 Physical and chemical indicators
Item Index Test Method
Acid red (azo-erythropo red) content, w /% ≥ 85.0 Appendix A, A.3
Dry reduction, chloride (in terms of NaCl) and sulfate ≤
(In terms of Na2SO4), w /%
15.0 Appendix A, A.4
Water insoluble matter, w /% ≤ 0.20 Appendix A, A.5
Sub-dye, w /% ≤ 1.0 Appendix A A.6
The sum of the unreacted raw materials, w /% ≤ 0.50 A.7 in Appendix A
Unsulfonated aromatic primary amine (in aniline), w /% ≤ 0.01 A.8 in Appendix A.
Total arsenic (in As)/(mg/kg) ≤ 1.0 GB/T 5009.11
Lead (Pb)/(mg/kg) ≤ 2.0 GB 5009.12
Appendix A
Testing method
A.1 General provisions
The reagents and water used in this standard, when not specified in other requirements, refers to the analysis of pure reagents and GB/T 6682-2008 of the three
water. Standard solution used in the test, the standard solution of impurities, preparations and products, in the absence of other requirements, according to GB/T 601,
GB/T 602, GB/T 603. The solution used in the experiment, when not specified with the preparation of the solvent, refers to the aqueous solution.
A.2 Identification test
A.2.1 Reagents and materials
A.2.1.1 Sulfuric acid.
A.2.1.2 Ammonium acetate solution. 1.5 g/L.
A.2.2 Instruments and equipment
A.2.2.1 Spectrophotometer.
A.2.2.2 Cuvette. 10mm.
A.2.3 Identification method
A.2.3.1 Weigh about 0.1g of sample, accurate to 0.01g, dissolved in 100mL water, the solution is clear red.
A.2.3.2 Weigh about 0.1g sample, accurate to 0.01g, add 10mL sulfuric acid, the solution was red, take this solution 2 to 3 drops in 5mL water
, The solution was red.
A.2.3.3 Weigh about 0.1g sample, accurate to 0.01g, dissolved in 100mL ammonium acetate solution, take 1mL of this solution, add ammonium acetate solution
Liquid to 100 mL, and the maximum absorption wavelength of the solution is 516 nm ± 2 nm.
A.3 Determination of acid red (azo-erythropoene) content
A.3.1 Titanium trichloride titration (Arbitration)
A.3.1.1 Method Summary
In the acidic medium, the azo group in the acid red (azo-erythropo red) is reduced and decomposed by titanium trichloride, and the solution is titrated according to the standard titration solution of titanium trichloride
Consumption, calculate the acid red (azo jade red) content.
A.3.1.2 Reagents and materials
A.3.1.2.1 trisodium citrate.
A.3.1.2.2 Titanium trichloride standard titration solution. c (TiCl3) = 0.1mol/L (now with the use of the preparation method see Appendix B).
A.3.1.2.3 Carbon dioxide.
A.3.1.3 Instruments and equipment
See Figure A.1.
A - conical flask (500mL);
B - brown burette (50mL);
C --- black paper with black paper bottle (2000mL);
D - container (5000 mL) containing 100 g/L ammonium carbonate solution and 100 g/L ferrous sulfate solution in equal volume;
E --- piston
F - empty bottle;
G --- water washing gas bottle.
Figure A.1 Titanium trichloride titration device
A.3.1.4 Analysis steps
Approximately 0.5 g of the sample was weighed to 0.0001 g, placed in a 500 mL Erlenmeyer flask, 50 mL of freshly boiled and cooled to room temperature
Water, dissolve, add 15g trisodium citrate and 150mL fresh boil and cool to room temperature water, shake dissolved, according to Figure A.1 installed the instrument,
While the carbon dioxide is fed under the liquid level, it is heated to boiling and titrated with titanium titanate titration solution until its inherent color disappears as the end point.
A.3.1.5 Calculation of results
Acid red (azo-erythropo red) content in mass fraction w1, the value in%, calculated according to formula (A.1).
w1 = c
(V/1000) (M/4)
m1 ×
100% (A.1)
Where.
c - Titanium trichloride standard titration solution concentration of the exact value in moles per liter (mol/L);
V --- titration sample consumption of titanium trichloride standard titration solution volume of the exact value in milliliters (mL);
1000 --- volume conversion factor;
M is the molar mass of acid red (azo-erythropo red) in grams per mole (g/mol) [M (C20H12N2Na2O7S2) =
502.43];
4 --- concentration conversion factor;
m1 --- the value of the sample quality, in grams (g).
The experimental results are based on the arithmetic mean of the parallel measurement results (leave a decimal). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 1.0%.
A.3.2 Spectrophotometric colorimetric method
A.3.2.1 Methodological Summary
The sample and the known content of acid red (azo-yu red) standard were dissolved in water, diluted with ammonium acetate solution volume, the maximum suction
Close the wavelength, respectively, measured its absorbance value, and then calculate its content.
A.3.2.2 Reagents and materials
A.3.2.2.1 Ammonium acetate solution. 1.5 g/L.
A.3.2.2.2 Acid red (azo jade red) Standard. ≥85.0% (mass fraction, measured according to A.3.1).
A.3.2.3 Instruments and equipment
A.3.2.3.1 Spectrophotometer.
A.3.2.3.2 Cuvette. 10mm.
A.3.2.4 Analysis steps
A.3.2.4.1 Preparation of Acid Red (Azo-Red) Standard Solution
Weigh about 0.25g acid red (azo jade red) standard, accurate to 0.0001g, dissolved in water, into the 1000mL volumetric flask
In the water diluted and fixed to the scale, shake. Absorb 10mL, into the 500mL volumetric flask, add ammonium acetate solution diluted and constant volume to the moment
Degree, shake, spare.
A.3.2.4.2 Preparation of Acid Red (Azo-Red) Sample Solution
Weighing and operating methods with A.3.2.4.1 standard solution preparation.
A.3.2.4.3 Determination
Take the appropriate amount of acid red (azo jade red) standard solution and acid red (azo jade red) sample solution, were placed in 10mm cuvette, the same
The respective absorbance values were measured with a spectrophotometer at the maximum absorption wavelength (516 nm ± 2 nm), and the ammonium acetate solution was used as the reference solution.
A.3.2.5 Calculation of results
Acid red (azo-erythropo red) content in mass fraction w2, the value in%, according to formula (A.2) calculation.
w2 = Am0A0m ×
w0 (A.2)
Where.
A - acid red (azo jade red) sample solution absorbance value;
m0 --- acid red (azo-red) standard product quality value, the unit is grams (g);
A0 --- acid red (azo jade red) standard solution absorbance value;
m - the mass of the sample, in grams (g);
w0 --- acid red (azo jade red) standard content of the value,%.
The experimental results are based on the arithmetic mean of the parallel measurement results (leave a decimal). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 1.0%.
A.4 Determination of dry reduction, total amount of chloride (in terms of NaCl) and sulfate (calculated as Na2SO4)
A.4.1 Determination of dry reduction
A.4.1.1 Analysis steps
Weigh about 2g sample, accurate to 0.001g, placed in 135 ℃ ± 2 ℃ constant temperature drying box constant weighing bottle, at 135 ℃ ± 2 ℃
Constant temperature drying oven to constant volume.
A.4.1.2 Calculation of results
The drying loss is expressed in terms of mass fraction w3 and the value in%, calculated according to formula (A.3)
w3 = m2-m3m2 ×
100% (A.3)
Where.
m2 --- the value of the sample before drying, in grams (g);
m3 --- the value of the sample after drying to constant volume, in grams (g).
The experimental results are based on the arithmetic mean of the parallel measurement results (leave a decimal). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 0.2%.
A.4.2 Determination of chloride (in terms of NaCl)
A.4.2.1 Reagents and materials
A.4.2.1.1 Nitrobenzene.
A.4.2.1.2 Activated carbon. 767 needle type.
A.4.2.1.3 Nitric acid solution. 1 1.
A.4.2.1.4 Silver nitrate solution. c (AgNO3) = 0.1 mol/L.
A.4.2.1.5 ammonium ferric sulfate solution. Weigh about 14g ammonium ferric sulfate, dissolved in 100mL water, filtered, add 10mL nitric acid, stored in brown
Color bottle.
A.4.2.1.6 Ammonium thiocyanate standard titration solution. c (NH4CNS) = 0.1mol/L.
A.4.2.2 Analysis steps
A.4.2.2.1 Preparation of sample solution
Weigh about 2g sample, accurate to 0.001g, dissolved in 150mL water, add about 15g activated carbon, gently boil 2min ~ 3min, plus
Into 1mL nitric acid solution, constantly shaking evenly, placed 30min (during which time shaking). Filter with dry filter paper. If the filtrate is colored, then again
Add 5g activated carbon, from time to time shaking under 1h, and then filter the dry filter paper (if there is still color is replaced by activated carbon repeated operation to the filtrate colorless).
Each time to 10mL water activated carbon three times, the filtrate combined into the.200mL volumetric flask, add water to the mark, shake. For chlorides and sulfur
Determination of acid salt content.
A.4.2.2.2 Determination
Remove the 50 mL sample solution, place in a 500 mL Erlenmeyer flask, add 2 mL of nitric acid solution and 10 mL of silver nitrate solution (chloride containing
The amount of time to add more) and 5mL nitrobenzene, shake to silver chloride condensation, add 1mL ammonium ferric sulfate solution, with ammonium thiocyanate standard
Titration solution titrated excess silver nitrate to the end and hold for 1 min, while the same method to do a blank test.
A.4.2.3 Calculation of results
Chloride (in terms of NaCl) is expressed as a mass fraction of w4, expressed in%, calculated according to formula (A.4)
w4 = c1
[(V1-V0)/1000] M1
m4 (50/200) x
100% (A.4)
Where.
c1 --- ammonium thiocyanate standard titration solution concentration of the exact value, the unit is mol per liter (mol/L);
V1 --- titration blank solution consumption of ammonium thiocyanate standard titration solution volume of the exact value in milliliters (mL);
V0 --- titration sample solution consumption of ammonium thiocyanate standard titration solution volume of the exact value in milliliters (mL);
1000 --- volume conversion factor;
M1 --- sodium chloride molar mass value in grams per mole (g/mol) [M1 (NaCl) = 58.4];
m4 --- the value of the sample quality, in grams (g);
50/200 --- dilution factor.
The experimental results are based on the arithmetic mean of the parallel measurement results (leave a decimal). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 0.3%.
A.4.3 Determination of Sulfate (calculated as Na2SO4)
A.4.3.1 Reagents and materials
A.4.3.1.1 Sodium hydroxide solution. 0.2 g/L.
A.4.3.1.2 Hydrochloric acid solution. 1 99.
A.4.3.1.3 barium chloride standard titration solution. c (1/2BaCl2) = 0.1mol/L (see Appendix C for the preparation method).
A.4.3.1.4 phenolphthalein indicator solution. 10g/L.
A.4.3.1.5 Sodium Roseate Indicator. Weigh 0.1 g of sodium rosin sodium and dissolve in 10 mL of water (now available).
A.4.3.2 Analysis steps
Absorb 25mL sample solution (A.4.2.2.1), placed in 250mL Erlenmeyer flask, add 1 drop of phenolphthalein indicator solution, add sodium hydroxide solution
Liquid was pink, and then dropping hydrochloric acid solution to pink disappeared, shake, dissolved in the constant shaking with barium chloride standard titration solution titration,
With sodium alanate indicator liquid for the external indicator solution, the reaction solution and indicator liquid on the filter paper at the intersection of rose red spots and keep 2min
Fade for the end. While the same method to do blank test.
A.4.3.3 Calculation of results
The content of sulfate (in terms of Na2SO4) is expressed in terms of mass fraction w5 and the value in%, calculated according to formula (A.5)
w5 = c2
[(V2-V3)/1000] (M2/2)
m5 (25/200) x
100% (A.5)
Where.
c2 --- barium chloride standard titration solution concentration of the exact value in moles per liter (mol/L);
V2 --- titration sample solution consumption of barium chloride standard titration solution volume of the exact value in milliliters (mL);
V3 --- titration blank solution consumption of barium chloride standard titration solution volume of the exact value in milliliters (mL);
1000 --- volume conversion factor;
(G/mol) [M2 (Na2SO4) = 142.04]; the mass of the mass fraction of sodium sulfate,
2 --- concentration conversion factor;
m5 --- the mass of the sample, in grams (g);
25/200 --- dilution factor.
The experimental results are based on the arithmetic mean of the parallel measurement results (leave a decimal). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 0.2%.
A.4.4 Calculation of dry reduction, chloride (calculated as NaCl) and sulfate (calculated as Na2SO4)
The total amount of dry reduction, chloride (in terms of NaCl) and sulfate (calculated as Na2SO4) is expressed in terms of mass fraction w6, expressed as%
Calculated according to formula (A.6).
w6 = w3 w4 w5 (A.6)
Where.
w3 --- dry reduction,%;
w4 --- chloride (in terms of NaCl) content,%;
w5 --- sulfate (in Na2SO4 dollars) content,%.
A.5 Determination of water insoluble matter
A.5.1 Instruments and equipment
A.5.1.1 Glass sand core crucible. G4, pore size of 5μm ~ 15μm.
A.5.1.2 Constant temperature oven.
A.5.2 Analysis steps
Weigh about 3g sample, accurate to 0.001g, placed in 500mL beaker, add 50 ℃ ~ 60 ℃ hot water 250mL, so that dissolved,
The mixture was filtered through a G4 glass sand core crucible which had been baked at 135 ° C ± 2 ° C and kept constant and washed with hot water until the washing solution was colorless at 135 ° C ± 2 ° C
Constant temperature drying oven to constant volume.
A.5.3 Calculation of results
Water insoluble matter in mass fraction w7, the value in%, according to formula (A.7).
w7 = m6m7 ×
100% (A.7)
Where.
m6 --- the value of the water insoluble matter after drying, in grams (g);
m7 --- the value of the sample quality, in grams (g).
The experimental results are based on the arithmetic mean of the parallel measurement results (whichever is two decimal places). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 0.05%.
A.6 Determination of secondary dyes
A.6.1 Methodological summary
The components were separated, eluted and then quantitated by spectrophotometry.
A.6.2 Reagents and materials
A.6.2.1 anhydrous ethanol.
A.6.2.2 n-butanol.
A.6.2.3 Acetone solution. 1 1.
A.6.2.4 Ammonia solution. 4 96.
A.6.2.5 Sodium bicarbonate solution. 4 g/L.
A.6.3 Instruments and equipment
A.6.3.1 Spectrophotometer.
A.6.3.2 chromatography filter paper. No. 1 medium speed, 150mm × 250mm.
A.6.3.3 chromatography cylinder. φ240mm × 300mm.
A.6.3.4 Micro Sampler. 100 μL.
A.6.3.5 Nessler's colorimetric tube. 50mL with a glass grinder.
A.6.3.6 glass sand core funnel. G3, aperture of 15μm ~ 40μm.
A.6.3.7 50mm cuvette.
A.6.3.8 10mm cuvette.
A.6.4 Analysis steps
A.6.4.1 Paper chromatography conditions
A.6.4.1.1 Expanding agent. n-butanol anhydrous ethanol ammonia solution = 6 2 3.
A.6.4.1.2 Temperature. 20 ° C to 25 ° C.
A.6.4.2 Preparation of sample solution
Weigh 1g sample, accurate to 0.001g, placed in a beaker, add the appropriate amount of water dissolved, into the 100mL volumetric flask, diluted to the moment
The amount of the sample solution is 1%.
A.6.4.3 Preparation of sample eluate
Use a micro-injector to draw 100 μL of the sample solution, evenly on a bottom line of 25 mm from the bottom of the filter paper,
Its width in the filter paper does not exceed 5mm, length of 130mm, with a hair dryer to dry. Place the filter paper in a pre-formulated developer
Of the column, the bottom edge of the filter paper immersed in the developer under the liquid surface 10mm, until the agent before the line rose to 150mm or until the dye
Separated from satisfaction. Remove the filter paper, dry with cold air.
With the blank filter paper under the same conditions to expand, the blank filter paper must be carried out with the above steps to use the filter paper on the same filter paper on the adjacent
Bit cut.
The chromatogram of the secondary dye paper is shown in Figure A.2.
Figure A.2 Schematic diagram of chromatographic analysis of secondary dyes
The respective sub-dyes obtained after the development and the filter paper on the blank filter paper corresponding to the respective sub-dyes are cut in the same size and
Cut into about 5mm × 15mm thin strips, were placed in 50mL Na colorimetric tube, accurately add 5mL acetone solution, shake
3min ~ 5min, and then accurately add 20mL sodium bicarbonate solution, shake, and then in the G3 glass sand core funnel naturally
Filter, the filtrate must be clear, no suspended solids. Respectively, to obtain the secondary dye and blank eluent. At the maximum absorption wavelength of the respective sub-dyes,
The eluent of each sub-dye was measured on a spectrophotometer using a 50 mm cuvette.
When the absorbance was measured on a spectrophotometer, a mixture of 5 mL of acetone solution and 20 mL of sodium bicarbonate solution was used as the reference solution.
A.6.4.4 Preparation of standard solutions
Absorb 2mL 1% of the sample solution into the 100mL volumetric flask, diluted to the mark, shake, the solution as the standard solution.
A.6.4.5 Preparation of standard eluate
Use a micro-injector to draw 100 μL of the standard solution, evenly point on the bottom of the filter paper 25mm on a baseline, with a hair dryer blowing
dry. The filter paper into a pre-prepared with a good preparation agent in the chromatography cylinder to start, before the agent to rise 40mm, take out with cold air blowing
Dry, cut all the expanded part of the dye, according to the method of A.6.4.3 extraction operation, get the standard eluent. With 10mm cuvette
Measure the absorbance at the maximum absorption wavelength.
At the same time with the blank filter paper under the same conditions to expand, according to the same method after the test wash the absorbance value.
A.6.4.6 Calculation of results
The content of the secondary dye is expressed in terms of mass fraction w8 and the value in%, calculated according to the formula (A.8)
w8 =
[(A1-b1) (An-bn)]/5
(AS-bS) (100/2) x
ws (A.8)
Where.
A1, and An - absorbance values of each sub-dye eluent at 50 mm optical path length;
b1, bn --- the absorbance value of each sub-dye control blank elution liquid measured with a 50 mm optical path length;
AS --- standard eluent to 10mm optical path length measured absorbance value;
bS --- standard control blank elution liquid to 10mm optical path length measured absorbance value;
5 --- converted into a 10mm optical path length ratio;
100/2 --- standard eluent converted into 1% sample solution ratio;
The mass fraction of acid red (azo - erythropo) in the sample.
The experimental results are based on the arithmetic mean of the parallel measurement results (leave a decimal). Two independent tests obtained under repetitive conditions
The absolute difference between the results is not more than 0.2%.
A.7 Determination of unreacted raw materials
A.7.1 Methodological Summary
The unreacted intermediates were quantitated by reverse phase liquid chromatography, and the total mass of unreacted intermediates was calculated
fraction.
A.7.2 Reagents and materials
A.7.2.1 acetonitrile.
A.7.2.2 Ammonium acetate solution. 15 g/L.
A.7.2.3 1-Naphthylamine-4-sulfonate.
A.7.2.4 1-Naphthol-4-sulfonate.
A.7.3 Instruments and equipment
A.7.3.1 Liquid Chromatograph. Infusion Pump - Flow range 0.1mL/min ~ 5.0mL/min, in which the flow stability is
± 1%.
A.7.3.2 Detector. Multi-wavelength UV spectrophotometer or UV spectrophotometer with equivalent performance.
A.7.3.3 Column. A stainless steel column with a length of 150 mm and an inner diameter of 4.6 mm. The stationary phase is C18 and has a particle size of 5 μm.
A.7.3.4 Chromatographic Workstation or Integrator.
A.7.3.5 Ultrasonic generator.
A.7.3.6 Dosing ring. 20 μL.
A.7.4 Reference chromatographic conditions
A.7.4.1 Detection wavelength. 254 nm.
A.7.4.2 Column temperature. 30 ° C.
A.7.4.3 mobile phase. A. ammonium acetate solution; B. acetonitrile. Concentration gradient. 35 min linear concentration gradient from A. B (100. 0) to A. B
(60.40), and then 5 min linear concentration gradient from A. B (60.40) to A. B (0.100).
A.7.4.4 Flow rate. 1.0 mL/min.
A.7.4.5 Injection volume. 20 μL.
According to the different instruments, select the best analysis conditions, the corresponding shake after the flow with ultrasonic generator degassing.
A.7.5 Preparation of sample solution
Weigh about 0.1g acid red (azo-yuhong red) sample, accurate to 0.0001g, add ammonium acetate solution dissolved and set to 100mL.
A.7.6 Preparation of standard solutions
Approximately 0.01 g, accurate to 0.0001 g, and 1-naphthylamine-4-sulfonate standard after drying in a vacuum drier for 24 h
4-hydroxy-1-naphthalenesulfonate standard. With ammonium acetate solution were dissolved and set to 100mL. And then were drawn 10.0mL,
5.0 mL, 2.0 mL, 1.0 mL each of the above standard solutions, and fixed to 100 mL with ammonium acetate solution to prepare a standard concentration
Solution.
A.7.7 Analysis steps
Under the reference chromatographic conditions of A.7.4, the sample solution and the standard solution of the concentration were sampled with a micro-syringe, respectively, and filled and filled
Quantitative loop for chromatographic detection, to be the last component outflow, the results of processing. The peak area of each standard solution was determined
Drawn into the standard curve. The peak area of sodium 1-naphthylamine-4-sulfonate and 1-naphthol-4-sulfonate in the sample solution was measured according to each standard curve
The content (w9) of 1-naphthylamine-4-sulfonate and the content (w10) of 1-naphthol-4-sulfonate were determined. (See Appendix D. for reference chromatograms)
A.7.8 Calculation of results
The sum of the unreacted raw materials is expressed in terms of mass fraction w11 and the value in%, calculated according to formula (A.9)
w11 = w9 w10 (A.9)
Where.
w9 --- 1-naphthylamine-4-sulfonate content,%;
w10 --- 1-naphthol-4-sulfonate content,%.
A.8 Determination of unsulfonated aromatic primary amines (on aniline)
A.8.1 Methodological Summary
The non-sulfonated aromatic primary amine component of the sample was extracted with ethyl acetate, and the extract and the aniline standard solution were respectively diazotized and coupled
And then determine the absorbance of their respective dyes to be compared and identified.
A.8.2 Reagents and materials
A.8.2.1 Ethyl acetate.
A.8.2.2 Hydrochloric acid solution. 1 10.
A.8.2.3 Hydrochloric acid solution. 1 3.
A.8.2.4 Potassium Bromide Solution. 500 g/L.
A.8.2.5 Sodium carbonate solution..200 g/L.
A.8.2.6 Sodium hydroxide solution. 40 g/L.
A.8.2.7 Sodium hydroxide solution. 4 g/L.
A.8.2.8 R salt solution. 2-naphthol-3,6-disulfonic acid disodium salt solution at a concentration of 20 g/L.
A.8.2.9 Sodium nitrite solution. 3.52 g/L.
A.8.2.10 Aniline standard solution. 0.1000 g/L. Weigh 0.5000 g of freshly distilled aniline in a small beaker and move to a 500 mL volumetric flask
, The beaker was washed three times with 150 mL hydrochloric acid solution (A.8.2.3), incorporated into a 500 mL volumetric flask, and diluted to a scale with water. Remove
25 mL of the solution to another 250 mL volumetric flask and set to vo...
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GB 28309-2012: Food Additives Acid Red (azo Indirubin)
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