GB 25585-2010 English PDF

GB 25585-2010: National food safety standards of food additive potassium chloride
Delivery: 9 seconds. Download (and Email) true-PDF + Invoice.
Get Quotation: Click GB 25585-2010 (Self-service in 1-minute)
Historical versions (Master-website): GB 25585-2010
Preview True-PDF (Reload/Scroll-down if blank)


GB 25585-2010
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard - Food additive -
Potassium chloride
ISSUED ON: DECEMBER 21, 2010
IMPLEMENTED ON: FEBRUARY 21, 2011
Issued by: Ministry of Health of the People's Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Molecular formula and relative molecular mass ... 4
4 Technical requirements ... 4
Appendix A (Normative) Test methods ... 6
National food safety standard - Food additive -
Potassium chloride
1 Scope
This Standard applies to potassium chloride produced from rock salt carnallite or sea
salt with magnesium chloride and potassium chloride as main components, and
potassium chloride obtained through refining as a food additive.
2 Normative references
The documents referenced in this Standard are indispensable for the application of this
Standard. For dated references, only the dated edition applies to this Standard. For
undated references, the latest edition (including all amendments) applies to this
Standard.
3 Molecular formula and relative molecular mass
3.1 Molecular formula
KCl
3.2 Relative molecular mass
74.55 (according to the international relative atomic mass in 2007)
4 Technical requirements
4.1 Sensory requirements: shall meet the requirements of Table 1.
4.2 Physical and chemical indicators: shall meet the requirements of Table 2.
Appendix A
(Normative)
Test methods
A.1 Warning
Some of the reagents used in the test methods of this Standard are toxic or corrosive,
and they must be handled with care! If it is splashed on the skin, use water to rinse it
immediately. If it is serious, seek medical attention immediately. When using volatile
acids, work in a fume hood.
A.2 General
The reagents and water used in the test methods of this Standard, unless otherwise
specified, refer to analytically pure reagents and grade-III water specified in GB 6682-
2008. The standard solutions, impurity standard solutions, preparations and products
required in the tests of this Standard shall be prepared in accordance with the provisions
of HG/T 3696.1, HG/T 3696.2 and HG/T 3696.3 unless other requirements are specified.
A.3 Identification test
A.3.1 Identification of potassium ions
Weigh about 2 g of the sample; place it in a beaker; add about 10 mL of water to dissolve
it. Soak the platinum wire of a glass rod (with a platinum wire ring on the top) in
hydrochloric acid and burn it on a flame until it becomes colorless; then, dip it in a
small amount of test solution and burn it on a flame. It shall show a purple flame under
the cobalt glass.
A.3.2 Identification of chloride ions
Take the sample solution (A.3.1) and add silver nitrate solution (10 g/L) to produce a
white precipitate which is insoluble in nitric acid.
A.4 Determination of potassium chloride
A.4.1 Method summary
Same as Chapter 2 of GB/T 3050-2000.
A.4.2 Reagents and materials
A.4.2.1 Nitric acid solution: 1+1.
A.4.2.2 Saturated potassium nitrate solution.
A.4.2.3 Bromophenol blue indicator solution: 1 g/L ethanol solution.
A.4.2.4 Silver nitrate standard titration solution: c(AgNO3) ≈ 0.1 mol/L.
A.4.3 Instruments and apparatuses
A.4.3.1 Potentiometer: The graduation value is 2 mV and the range is -500 mV ~ +500
mV.
A.4.3.2 Reference electrode: double liquid junction saturated calomel electrode.
A.4.3.3 Measuring electrode: silver electrode.
A.4.4 Analysis steps
Weigh about 0.25 g of the sample dried for 2 h according to A.5, accurate to 0.0001 g;
place it in a 100 mL beaker; add 40 mL of water to dissolve; add 1 drop of bromophenol
blue indicator solution; add 1 to 2 drops of nitric acid solution to make the solution just
yellow; use a standard silver nitrate titration solution with a concentration of about 0.1
mol/L; follow the steps in 4.6 of GB/T 3050-2000 starting from "Put in an
electromagnetic stirrer..."; record the total volume and corresponding potential value
after each addition of the standard silver nitrate titration solution; calculate the volume
(V) of the standard silver nitrate titration solution consumed by the titration to the
endpoint.
A.4.5 Result calculation
The potassium chloride content is calculated based on the mass fraction w1 of potassium
chloride (KCl), and the value is expressed in %, calculated according to Formula (A.1):
Where:
V – the value of the volume of the silver nitrate standard titration solution consumed in
the titration, in milliliters (mL);
c – the exact value of the concentration of the silver nitrate standard titration solution,
in moles per liter (mol/L);
w0 – the value of the mass fraction of the loss on drying measured in A.5, expressed
in %;
m – the value of the sample mass, in grams (g);
M – the value of the molar mass of potassium chloride (KCl), in grams per mole (g/mol)
(M = 74.55).
A.6.2 Analysis steps
Weigh about 5 g of the sample and dissolve it in 50 mL of freshly prepared carbon
dioxide-free water. After adding 3 drops of phenolphthalein indicator solution, the
solution shall not show pink. After adding 0.3 mL of sodium hydroxide standard
titration solution, the test solution shall show pink.
A.7 Determination of iodine and bromine
A.7.1 Reagents and materials
A.7.1.1 Trichloromethane.
A.7.1.2 Sodium hypochlorite solution.
A.7.2 Analysis steps
Weigh 2 g of the sample to an accuracy of 0.01 g; place it in a 25 mL colorimetric tube;
add 6 mL of water and dissolve. Add 1 mL of trichloromethane; then, dropwise add 5
mL of sodium hypochlorite solution while shaking the colorimetric tube. The
trichloromethane layer shall not show any temporary purple or permanent orange color.
A.8 Determination of sodium
A.8.1 Reagents and materials
A.8.1.1 Hydrochloric acid: guaranteed reagent.
A.8.1.2 Stock solution of sodium standard solution: 1 mL of solution contains 0.1 mg
of sodium (Na).
Preparation: Use a pipette to transfer 10 mL of the sodium standard solution prepared
according to HG/T 3696.2 into a 100 mL volumetric flask; dilute to the mark; shake
well.
A.8.1.3 Sodium standard solution: 1 mL of solution contains 0.01 mg of sodium (Na).
Preparation: Use a pipette to transfer 10 mL of sodium standard solution stock solution
(A.8.1.2) into a 100 mL volumetric flask; dilute to the mark; shake well.
A.8.1.4 Cesium chloride solution: 20 g/L.
Weigh 2 g of cesium chloride (spectrally pure); place it in a 100 mL beaker; add an
appropriate amount of water to dissolve it completely; use water to dilute to 100 mL;
shake well. Store in plastic bottles.
A.8.1.5 Acetylene: high purity.
A.8.1.6 Water: Grade-II water in accordance with GB/T 6682-2008.
GB 25585-2010
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard - Food additive -
Potassium chloride
ISSUED ON: DECEMBER 21, 2010
IMPLEMENTED ON: FEBRUARY 21, 2011
Issued by: Ministry of Health of the People's Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Molecular formula and relative molecular mass ... 4
4 Technical requirements ... 4
Appendix A (Normative) Test methods ... 6
National food safety standard - Food additive -
Potassium chloride
1 Scope
This Standard applies to potassium chloride produced from rock salt carnallite or sea
salt with magnesium chloride and potassium chloride as main components, and
potassium chloride obtained through refining as a food additive.
2 Normative references
The documents referenced in this Standard are indispensable for the application of this
Standard. For dated references, only the dated edition applies to this Standard. For
undated references, the latest edition (including all amendments) applies to this
Standard.
3 Molecular formula and relative molecular mass
3.1 Molecular formula
KCl
3.2 Relative molecular mass
74.55 (according to the international relative atomic mass in 2007)
4 Technical requirements
4.1 Sensory requirements: shall meet the requirements of Table 1.
4.2 Physical and chemical indicators: shall meet the requirements of Table 2.
Appendix A
(Normative)
Test methods
A.1 Warning
Some of the reagents used in the test methods of this Standard are toxic or corrosive,
and they must be handled with care! If it is splashed on the skin, use water to rinse it
immediately. If it is serious, seek medical attention immediately. When using volatile
acids, work in a fume hood.
A.2 General
The reagents and water used in the test methods of this Standard, unless otherwise
specified, refer to analytically pure reagents and grade-III water specified in GB 6682-
2008. The standard solutions, impurity standard solutions, preparations and products
required in the tests of this Standard shall be prepared in accordance with the provisions
of HG/T 3696.1, HG/T 3696.2 and HG/T 3696.3 unless other requirements are specified.
A.3 Identification test
A.3.1 Identification of potassium ions
Weigh about 2 g of the sample; place it in a beaker; add about 10 mL of water to dissolve
it. Soak the platinum wire of a glass rod (with a platinum wire ring on the top) in
hydrochloric acid and burn it on a flame until it becomes colorless; then, dip it in a
small amount of test solution and burn it on a flame. It shall show a purple flame under
the cobalt glass.
A.3.2 Identification of chloride ions
Take the sample solution (A.3.1) and add silver nitrate solution (10 g/L) to produce a
white precipitate which is insoluble in nitric acid.
A.4 Determination of potassium chloride
A.4.1 Method summary
Same as Chapter 2 of GB/T 3050-2000.
A.4.2 Reagents and materials
A.4.2.1 Nitric acid solution: 1+1.
A.4.2.2 Saturated potassium nitrate solution.
A.4.2.3 Bromophenol blue indicator solution: 1 g/L ethanol solution.
A.4.2.4 Silver nitrate standard titration solution: c(AgNO3) ≈ 0.1 mol/L.
A.4.3 Instruments and apparatuses
A.4.3.1 Potentiometer: The graduation value is 2 mV and the range is -500 mV ~ +500
mV.
A.4.3.2 Reference electrode: double liquid junction saturated calomel electrode.
A.4.3.3 Measuring electrode: silver electrode.
A.4.4 Analysis steps
Weigh about 0.25 g of the sample dried for 2 h according to A.5, accurate to 0.0001 g;
place it in a 100 mL beaker; add 40 mL of water to dissolve; add 1 drop of bromophenol
blue indicator solution; add 1 to 2 drops of nitric acid solution to make the solution just
yellow; use a standard silver nitrate titration solution with a concentration of about 0.1
mol/L; follow the steps in 4.6 of GB/T 3050-2000 starting from "Put in an
electromagnetic stirrer..."; record the total volume and corresponding potential value
after each addition of the standard silver nitrate titration solution; calculate the volume
(V) of the standard silver nitrate titration solution consumed by the titration to the
endpoint.
A.4.5 Result calculation
The potassium chloride content is calculated based on the mass fraction w1 of potassium
chloride (KCl), and the value is expressed in %, calculated according to Formula (A.1):
Where:
V – the value of the volume of the silver nitrate standard titration solution consumed in
the titration, in milliliters (mL);
c – the exact value of the concentration of the silver nitrate standard titration solution,
in moles per liter (mol/L);
w0 – the value of the mass fraction of the loss on drying measured in A.5, expressed
in %;
m – the value of the sample mass, in grams (g);
M – the value of the molar mass of potassium chloride (KCl), in grams per mole (g/mol)
(M = 74.55).
A.6.2 Analysis steps
Weigh about 5 g of the sample and dissolve it in 50 mL of freshly prepared carbon
dioxide-free water. After adding 3 drops of phenolphthalein indicator solution, the
solution shall not show pink. After adding 0.3 mL of sodium hydroxide standard
titration solution, the test solution shall show pink.
A.7 Determination of iodine and bromine
A.7.1 Reagents and materials
A.7.1.1 Trichloromethane.
A.7.1.2 Sodium hypochlorite solution.
A.7.2 Analysis steps
Weigh 2 g of the sample to an accuracy of 0.01 g; place it in a 25 mL colorimetric tube;
add 6 mL of water and dissolve. Add 1 mL of trichloromethane; then, dropwise add 5
mL of sodium hypochlorite solution while shaking the colorimetric tube. The
trichloromethane layer shall not show any temporary purple or permanent orange color.
A.8 Determination of sodium
A.8.1 Reagents and materials
A.8.1.1 Hydrochloric acid: guaranteed reagent.
A.8.1.2 Stock solution of sodium standard solution: 1 mL of solution contains 0.1 mg
of sodium (Na).
Preparation: Use a pipette to transfer 10 mL of the sodium standard solution prepared
according to HG/T 3696.2 into a 100 mL volumetric flask; dilute to the mark; shake
well.
A.8.1.3 Sodium standard solution: 1 mL of solution contains 0.01 mg of sodium (Na).
Preparation: Use a pipette to transfer 10 mL of sodium standard solution stock solution
(A.8.1.2) into a 100 mL volumetric flask; dilute to the mark; shake well.
A.8.1.4 Cesium chloride solution: 20 g/L.
Weigh 2 g of cesium chloride (spectrally pure); place it in a 100 mL beaker; add an
appropriate amount of water to dissolve it completely; use water to dilute to 100 mL;
shake well. Store in plastic bottles.
A.8.1.5 Acetylene: high purity.
A.8.1.6 Water: Grade-II water in accordance with GB/T 6682-2008.