GB 29207-2012 English PDF

GB 29207-2012: Food additive magnesium
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GB 29207-2012
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard - Food Additive - Magnesium
Sulfate
ISSUED ON: DECEMBER 25, 2012
IMPLEMENTED ON: JANUARY 25, 2013
Issued by: Ministry of Health of the People’s Republic of China
Table of Contents
1 Scope ... 3
2 Chemical Name, Molecular Formula and Relative Molecular Mass ... 3
3 Technical Requirements ... 4
Appendix A Inspection Methods ... 5
National Food Safety Standard - Food Additive - Magnesium
Sulfate
1 Scope
This Standard applies to magnesium sulfate, a food additive produced from natural magnesium
carbonate (magnesite), sulfuric acid, magnesium vanadium sulfide and seawater.
2 Chemical Name, Molecular Formula and Relative
Molecular Mass
2.1 Chemical name
Anhydrous magnesium sulfate
Magnesium sulfate monohydrate
Magnesium sulfate trihydrate
Magnesium sulfate heptahydrate
Dried magnesium sulfate
2.2 Molecular formula
Anhydrous magnesium sulfate: MgSO4
Magnesium sulfate monohydrate: MgSO4 · H2O
Magnesium sulfate trihydrate: MgSO4 · 3H2O
Magnesium sulfate heptahydrate: MgSO4 · 7H2O
Dried magnesium sulfate: MgSO4 ·nH2O (n is the average value of hydration, between 2 and 3)
2.3 Relative molecular mass
Anhydrous magnesium sulfate: 120.37 (according to the 2007 international relative atomic
mass)
Appendix A
Inspection Methods
A.1 Warning
Some of the reagents used in the test methods of this Standard are toxic or corrosive, and
appropriate safety and protective measures shall be taken during operation.
A.2 General
The reagents and water used in this Standard, unless otherwise specified, refer to analytically
pure reagents and Grade-3 water specified in GB/T 6682-2008. The standard titration solutions,
standard solutions for impurity determination, preparations and products required in the test,
unless otherwise specified, are prepared in accordance with the provisions of GB/T 601, GB/T
602 and GB/T 603. The used solutions refer to aqueous solutions unless otherwise specified.
A.3 Identification test
A.3.1 Reagents and materials
A.3.1.1 Ammonium chloride solution: 200 g/L.
A.3.1.2 Ammonium carbonate solution: 200 g/L.
A.3.1.3 Sodium phosphate solution: 60 g/L.
A.3.1.4 Ammonia solution: 2+3.
A.3.1.5 Barium chloride solution: 100 g/L.
A.3.1.6 Hydrochloric acid solution: 1+1.
A.3.1.7 Lead acetate solution: 80 g/L.
A.3.1.8 Ammonium acetate solution: 100 g/L.
A.3.2 Identification method
A.3.2.1 Magnesium ion identification
Take about 0.5 g of specimen, dissolve in 10 mL of water; add 5 mL of ammonium chloride
solution and 5 mL of ammonium carbonate solution; stir; no precipitation is produced. Then
add 5 mL of sodium phosphate solution; produce white crystalline precipitation; add 10 mL of
ammonia solution, the white crystalline precipitation does not dissolve.
A.3.2.2 Sulfate ion identification
A.3.2.2.1 Take about 0.5 g of specimen, dissolve in 10 mL of water; add barium chloride
solution; produce white precipitation; this white precipitation is insoluble in hydrochloric acid
solution.
A.3.2.2.2 Take about 0.5 g of specimen, dissolve in 10 mL of water; add lead acetate solution;
produce white precipitation; this white precipitation is soluble in ammonium acetate solution.
A.3.2.2.3 Take about 0.5 g of the specimen, dissolve it in 10 mL of water; and add hydrochloric
acid without precipitation.
A.4 Determination of magnesium sulfate (MgSO4) content
A.4.1 Method summary
Add ammonia-ammonium chloride buffer solution A with a pH of ≈ 10 to the specimen solution;
use chrome black T as an indicator; and titrate the magnesium content with disodium
ethylenediaminetetraacetic acid (EDTA) standard titration solution.
A.4.2 Reagents and materials
A.4.2.1 Ammonia-ammonium chloride buffer solution A: pH ≈ 10.
A.4.2.2 Disodium ethylenediaminetetraacetic acid standard titration solution: c(EDTA) = 0.05
mol/L.
A.4.2.3 Chrome black T indicator.
A.4.3 Analysis procedures
Weigh about 1.5 g of the specimen burned according to A.9, accurate to 0.0002 g; place it in a
200 mL beaker; add 25 mL of water to dissolve. Then transfer to a 250 mL volumetric flask;
dilute to the mark with water; and shake well. Use a pipette to transfer 25 mL of the specimen
solution; place it in a 250 mL conical flask; add 25 mL of water; add 10 mL of ammonia-
ammonium chloride buffer solution A, a small amount of chrome black T indicator; and titrate
with disodium ethylenediaminetetraacetic acid standard titration solution until the solution
changes from purple-red to pure blue as the end point.
At the same time, perform the same blank test. Except for not adding the specimen to the blank
sample solution, the types and amounts of other added reagents (except the standard titration
solution) are the same as those of the specimen solution.
A.4.4 Calculation of results
The mass fraction, w1, of magnesium sulfate (MgSO4) content is calculated according to
Formula (A.1):
A.5.3 Analysis procedures
A.5.3.1 Cleaning of glassware
Soak in nitric acid solution (1+5) overnight; rinse repeatedly with tap water; and finally rinse
with water.
A.5.3.2 Preparation of specimen solution
Weigh about 5 g of specimen, accurate to 0.01 g; place in a 150 mL beaker; add 30 mL of water;
and add 1 mL of hydrochloric acid. Heat and boil for a few minutes; cool; and dilute with water
to 100 mL. Adjust the solution pH to 1.0~1.5 with sodium hydroxide solution. Transfer this
solution to a 250 mL separating funnel and dilute with water to about 200 mL. Add 2 mL of
ammonium pyrrolidine dithiocarbamate (APDC) solution and mix. Extract twice with 20 mL
of chloroform; collect the extract in a 50 mL beaker; evaporate to dryness in a steam bath (this
operation must be performed in a fume hood); add 3 mL of nitric acid to the residue; and
continue evaporating until nearly dry. Add 0.5 mL of nitric acid and 10 mL of water; and heat
until the solution volume is about 3 mL~5 mL. Transfer to a 10 mL volumetric flask; dilute to
scale with water; and shake well.
A.5.3.3 Preparation of blank specimen solution
Put 30 mL of water in a 150 mL beaker and add 1 mL of hydrochloric acid. The following
operations are the same as "heat and boil for a few minutes; cool; dilute to 100 mL with water ...
transfer to a 10 mL volumetric flask; dilute to scale with water; and shake well" in A.5.3.2.
A.5.3.4 Preparation of standard solution
Put 2.00 mL of lead standard solution in a 150 mL beaker and add 1 mL of hydrochloric acid.
The following operations are the same as "heat and boil for a few minutes; cool; dilute with
water to 100 mL ... transfer to a 10 mL volumetric flask; dilute to the scale with water; and
shake well" in A.5.3.2.
A.5.3.5 Analysis procedures
Introduce the specimen solution and standard solution into the atomic absorption
spectrophotometer; use air-acetylene flame at a wavelength of 283.3 nm and adjust to zero with
the blank sample solution; and measure the absorbance. The absorbance of the specimen
solution shall be no higher than that of the standard solution.
A.6 Determination of selenium (Se)
A.6.1 Reagents and materials
A.6.1.1 Hydroxylamine hydrochloride.
A.6.1.2 Cyclohexane.
A.6.1.3 Hydrochloric acid solution: 1+1.
A.6.1.4 Ammonia solution: 1+1.
A.6.1.5 2,3-Diaminonaphthalene solution: Weigh 0.1 g of 2,3-diaminonaphthalene and 0.5 g of
hydroxylamine hydrochloride; dissolve in 0.1 mol/L hydrochloric acid solution to make 100
mL of solution.
A.6.1.6 Selenium (Se) standard solution: 0.01 mg/mL.
A.6.2 Apparatuses
Spectrophotometer, equipped with a cuvette with an optical length of 1 cm.
A.6.3 Analysis procedures
Weigh about 1 g of the specimen, accurate to 0.000 2 g; place in a 150 mL beaker; add 25 mL
of water; 5 mL of hydrochloric acid solution; stir; heat and boil for 15 min; and cool. Adjust the
pH to 2±0.2 (check with precision pH test paper) with ammonia solution; add 0.2 g of
hydroxylamine hydrochloride; stir until dissolved. Immediately add 5 mL of 2,3-
diaminonaphthalene solution; and mix well. Cover with a watch glass and stand at room
temperature for 100 min. Then transfer all to a 125 mL separating funnel and add water to about
60 mL. Add 10 mL of cyclohexane with a pipette; shake vigorously for 2 min; stand and
separate; and discard the water layer. Use a 1 cm colorimetric tube to measure the absorbance
at a wavelength of about 380 nm with water as a reference. The absorbance shall be no greater
than the standard.
The standard is to pipette 3 mL of selenium standard solution and treat it in the same way as
the specimen at the same time.
A.7 Determination of chloride (as Cl)
Weigh 1.00 g ± 0.01 g of the specimen; place it in a 50 mL beaker; and add 10 mL of water to
dissolve the specimen. Then transfer all of it to a 50 mL colorimetric tube; add 2 mL of silver
nitrate solution (17 g/L) and 1 mL of nitric acid solution (1+2); then add water to the scale and
shake well. Place it in a dark place for 10 min. Compared with the standard turbidity solution,
its turbidity shall be no darker than the standard.
The standard turbidity solution is to pipette 3.00 mL of chlorine (Cl) standard solution (0.1
mg/mL) and place it in a 50 mL colorimetric tube. Treat it in the same way as the specimen
solution at the same time.
A.8 Determination of Iron (Fe)
A.8.1 Reagents and materials
A.8.1.1 Standard iron (Fe) solution: 0.01 mg/mL.
GB 29207-2012
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard - Food Additive - Magnesium
Sulfate
ISSUED ON: DECEMBER 25, 2012
IMPLEMENTED ON: JANUARY 25, 2013
Issued by: Ministry of Health of the People’s Republic of China
Table of Contents
1 Scope ... 3
2 Chemical Name, Molecular Formula and Relative Molecular Mass ... 3
3 Technical Requirements ... 4
Appendix A Inspection Methods ... 5
National Food Safety Standard - Food Additive - Magnesium
Sulfate
1 Scope
This Standard applies to magnesium sulfate, a food additive produced from natural magnesium
carbonate (magnesite), sulfuric acid, magnesium vanadium sulfide and seawater.
2 Chemical Name, Molecular Formula and Relative
Molecular Mass
2.1 Chemical name
Anhydrous magnesium sulfate
Magnesium sulfate monohydrate
Magnesium sulfate trihydrate
Magnesium sulfate heptahydrate
Dried magnesium sulfate
2.2 Molecular formula
Anhydrous magnesium sulfate: MgSO4
Magnesium sulfate monohydrate: MgSO4 · H2O
Magnesium sulfate trihydrate: MgSO4 · 3H2O
Magnesium sulfate heptahydrate: MgSO4 · 7H2O
Dried magnesium sulfate: MgSO4 ·nH2O (n is the average value of hydration, between 2 and 3)
2.3 Relative molecular mass
Anhydrous magnesium sulfate: 120.37 (according to the 2007 international relative atomic
mass)
Appendix A
Inspection Methods
A.1 Warning
Some of the reagents used in the test methods of this Standard are toxic or corrosive, and
appropriate safety and protective measures shall be taken during operation.
A.2 General
The reagents and water used in this Standard, unless otherwise specified, refer to analytically
pure reagents and Grade-3 water specified in GB/T 6682-2008. The standard titration solutions,
standard solutions for impurity determination, preparations and products required in the test,
unless otherwise specified, are prepared in accordance with the provisions of GB/T 601, GB/T
602 and GB/T 603. The used solutions refer to aqueous solutions unless otherwise specified.
A.3 Identification test
A.3.1 Reagents and materials
A.3.1.1 Ammonium chloride solution: 200 g/L.
A.3.1.2 Ammonium carbonate solution: 200 g/L.
A.3.1.3 Sodium phosphate solution: 60 g/L.
A.3.1.4 Ammonia solution: 2+3.
A.3.1.5 Barium chloride solution: 100 g/L.
A.3.1.6 Hydrochloric acid solution: 1+1.
A.3.1.7 Lead acetate solution: 80 g/L.
A.3.1.8 Ammonium acetate solution: 100 g/L.
A.3.2 Identification method
A.3.2.1 Magnesium ion identification
Take about 0.5 g of specimen, dissolve in 10 mL of water; add 5 mL of ammonium chloride
solution and 5 mL of ammonium carbonate solution; stir; no precipitation is produced. Then
add 5 mL of sodium phosphate solution; produce white crystalline precipitation; add 10 mL of
ammonia solution, the white crystalline precipitation does not dissolve.
A.3.2.2 Sulfate ion identification
A.3.2.2.1 Take about 0.5 g of specimen, dissolve in 10 mL of water; add barium chloride
solution; produce white precipitation; this white precipitation is insoluble in hydrochloric acid
solution.
A.3.2.2.2 Take about 0.5 g of specimen, dissolve in 10 mL of water; add lead acetate solution;
produce white precipitation; this white precipitation is soluble in ammonium acetate solution.
A.3.2.2.3 Take about 0.5 g of the specimen, dissolve it in 10 mL of water; and add hydrochloric
acid without precipitation.
A.4 Determination of magnesium sulfate (MgSO4) content
A.4.1 Method summary
Add ammonia-ammonium chloride buffer solution A with a pH of ≈ 10 to the specimen solution;
use chrome black T as an indicator; and titrate the magnesium content with disodium
ethylenediaminetetraacetic acid (EDTA) standard titration solution.
A.4.2 Reagents and materials
A.4.2.1 Ammonia-ammonium chloride buffer solution A: pH ≈ 10.
A.4.2.2 Disodium ethylenediaminetetraacetic acid standard titration solution: c(EDTA) = 0.05
mol/L.
A.4.2.3 Chrome black T indicator.
A.4.3 Analysis procedures
Weigh about 1.5 g of the specimen burned according to A.9, accurate to 0.0002 g; place it in a
200 mL beaker; add 25 mL of water to dissolve. Then transfer to a 250 mL volumetric flask;
dilute to the mark with water; and shake well. Use a pipette to transfer 25 mL of the specimen
solution; place it in a 250 mL conical flask; add 25 mL of water; add 10 mL of ammonia-
ammonium chloride buffer solution A, a small amount of chrome black T indicator; and titrate
with disodium ethylenediaminetetraacetic acid standard titration solution until the solution...