GB 5009.275-2016 PDF in English
GB 5009.275-2016 (GB5009.275-2016) PDF English
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Method for determination of Boric acid in Foods
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Standards related to (historical): GB 5009.275-2016
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GB 5009.275-2016: PDF in English GB 5009.275-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Boric Acid in Food
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of PRC;
China Food and Drug Administration.
3. No action is required - Full-copy of this standard will be automatically &
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Table of Contents
Foreword ... 3
1 Scope ... 4
2 Principle ... 4
3 Reagents and Materials ... 4
4 Apparatus ... 5
5 Analytical Procedures ... 6
6 Expression of Analytical Results ... 7
7 Precision ... 7
8 Others ... 7
National Food Safety Standard -
Determination of Boric Acid in Food
1 Scope
This Standard specifies the method for determination of boric acid in food.
This Standard is applicable to the determination of boric acid in the following foods
such as aquatic products, meat products (e.g. meatballs), beans, pasta, dried bean-
curd stick, rice dumplings, cookies, soy sauce, bean jelly, cold noodles, etc.
2 Principle
Rapidly enrich, extract the boric acid in the sample through the ethyl hexanediol-
chloroform solution; remove the effect of the coexisting salt; use the protonated
turmeric mixed through the sulfuric acid and turmeric to react with the boric acid to
generate red product. The color depth of the solution is proportional the amount of
boric acid in the sample; the boric acid content in the sample can be determined
through colorimetry.
3 Reagents and Materials
Unless otherwise is specified, the reagents used in this method is analytically pure;
while the used water is Class-III water stipulated in GB/T 6682.
3.1 Reagents
3.1.1 Sulfuric acid (H2SO4).
3.1.2 Anhydrous ethanol (CH3CH2OH).
3.1.3 Methanol (CH3OH).
3.1.4 Potassium ferrocyanide [K4Fe(CN)6•3H2O].
3.1.5 Zinc acetate [Zn(CH3COO)2•2H2O].
3.1.6 Curcumin.
3.1.7 Glacial acetic acid (CH3COOH).
4.4 Vortex oscillator.
5 Analytical Procedures
5.1 Specimen preparation
Solid sample. take 2g~10g (accurate to 0.01g) of sample mashed by high-speed
grinder into 150mL plastic beaker; add 40mL~60mL of water to mix evenly; slowly
titrate 2mL of sulfuric acid; perform ultrasound for 10min to promote the dissolution and
mixing. Add 5mL of zinc acetate solution; add 5mL of potassium ferrocyanide solution;
add water to make constant volume of 100mL; after filtration, it serves as the prepared
specimen solution. Pipette 1.00mL~3.00mL of prepared specimen solution according
to the sample content into 25mL plastic tube; add water to 5mL. Add 1mL of sulfuric
acid solution (1+1); shake evenly; add 5mL of EHD-CHCl3 solution; cover it; shake for
2min by the vortex oscillator; stand for stratification; pipette the lower-layer of EHD-
CHCl3 solution; filter by Φ7cm drying fast filter paper. The filtrate is used as the sample
test solution.
Liquid sample. take 2g~10g (accurate to 0.01g) of sample into 150mL plastic beaker;
add 40mL of water to mix evenly; add 5mL of zinc acetate solution; add 5mL of
potassium ferrocyanide solution; add water to make constant volume of 100mL; after
filtration, it serves as the prepared specimen solution. Pipette 1.00mL~3.00mL of
prepared specimen solution according to sample content into 25mL plastic tube; add
water to 5mL; add 1mL of sulfuric acid solution (1+1); shake evenly; add 5.00mL of
EHD-CHCl3 solution; cover it; shake for 2min by vortex oscillator; stand for stratification;
pipette the lower-layer EHD-CHCl3 solution; filter by Φ7cm drying fast filter paper. The
filtrate is used as the sample test solution.
NOTE. if the emulsification appears during the extraction process, the extracting solution can
be centrifuged for 3min at 3000r/min, or add 1mL of methanol into the measurement system to
avoid emulsification or precipitation phenomenon; for instance, the adding methanol shall keep
the water-adding constant-volume of 5mL.
5.2 Drawing of standard curve
Accurately pipette 0.00mL, 1.00mL, 2.00mL, 3.00mL, 4.00mL, 5.00mL of boric acid
standard solution into 25mL plastic tube; separately add water to 5mL. Add 1mL of
sulfuric acid solution (1+1); shake evenly; add 5.00mL of EHD-CHCl3 solution; cover it;
shake for 2min by the vortex oscillator; stand for stratification; pipette the lower-layer
EHD-CHCl3 solution; filter by Φ7cm drying fast filter paper.
Separately take 1.00mL of filtrate and place into 50mL plastic tube; successively add
1.0mL of turmeric-glacial acetic acid solution; 0.5mL of sulfuric acid; shake evenly;
stand for 30min; add 25mL of anhydrous ethanol; stand for 10min; measure the
absorbance at 550nm by 1cm cuvette. Draw the standard curve with the standard
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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