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This standard replaces GB 5175-2008 Food additive - Sodium hydroxide.
The following main changes have been made with respect to GB 5175-2008:
——The standard name is changed to “National food safety standard - Food additive - Sodium hydroxide”.
National food safety standard
Food additive - Sodium hydroxide
1 Scope
This standard is applicable to food additive sodium hydroxide.
2 Molecular formula and relative molecular mass
2.1 Molecular formula
NaOH
2.2 Relative molecular mass
40.00 (according to the international relative atomic mass in 2007)
3 Technical requirements
3.1 Sensory requirements
Sensory requirements shall meet those specified in Table 1.
Table 1 Sensory requirements
Item Requirement Inspection method
Solid sodium hydroxide Liquid sodium hydroxide
Color and luster White or nearly white Clear or slightly turbid,
colorless or pinkish Take a proper amount of specimen and put it into a clean and dry white porcelain dish, and observe its color and luster as well as state in natural light
State Solid Liquid
3.2 Physical and chemical indexes
Physical and chemical indexes shall meet those specified in Table 2.
Table 2 Physical and chemical indexes
Item Index Inspection method
Solid sodium hydroxide Liquid sodium hydroxide
Total alkali content (counted by NaOH), ω/% 98.0~100.5 98.0a~103.5a Annex A, A.4
Sodium carbonate (Na2CO3), ω/％ ≤ 2.0 Annex A, A.4
Arsenic (As)/(mg/kg) ≤ 3.0 GB 5009.76
Heavy metal (counted by Pb)/(mg/kg) ≤ 5 GB 5009.74
Insolubles and organic impurities Pass Annex A, A.5
Mercury (Hg)/ mg/kg ≤ 0.1 Annex A, A.6
a Converted according to the marked value of sodium hydroxide.
Annex A
Inspection method
A.1 Safety tips
The operator shall take care because certain regents adopted in the inspection of this standard are toxic or corrosive. In case of splashing to skin, rinse it immediately with water. In severe cases, seek medical treatment immediately. The highly toxic products, if used, shall be managed in strict accordance with relevant requirements; inhalation or contact with skin shall be avoided during using, and they shall be used in a fume hood when necessary.
A.2 General requirements
For the purpose of this standard, unless otherwise specified, all the reagents and water used refer to analytical reagents and Grade 3 water specified in GB/T 6682. For the purpose of this standard, unless otherwise specified, the standard solution, the standard solution for determination of impurities, preparations and products shall be prepared in accordance with GB/T 601, GB/T 602 and GB/T 603. Unless otherwise specified, the solution used in the tests refers to the aqueous solution.
A.3 Identification test
A.3.1 Identification of alkaline
The aqueous solution of this product can dissociate OH－, showing strong alkaline reaction.
Foreword i
1 Scope
2 Molecular formula and relative molecular mass
3 Technical requirements
Annex A Inspection method
