GB 5009.15-2023 PDF in English
GB 5009.15-2023 (GB5009.15-2023) PDF English
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| GB 5009.15-2023 | English | 140 |
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National food safety standard - Determination of cadmium in foods
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| GB 5009.15-2014 | English | 80 |
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National Food Safety Standard -- Determination of Cadmium in food
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| GB/T 5009.15-2003 | English | 399 |
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Determination of cadmium in foods
| Obsolete |
| GB/T 5009.15-1996 | English | 279 |
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Method for determination of cadmium in foods
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| GB 5009.15-1985 | English | 199 |
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Method for determination of cadmium in foods
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Standards related to (historical): GB 5009.15-2023
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GB 5009.15-2023: PDF in English GB 5009.15-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard - Determination of Cadmium
in Foods
ISSUED ON: SEPTEMBER 6, 2023
IMPLEMENTED ON: MARCH 6, 2024
Issued by: National Health Commission of the People’s Republic of China;
State Administration for Market Regulation.
Table of Contents
Foreword ... 3
1 Scope ... 4
Method I - Graphite Furnace Atomic Absorption Spectrometry ... 4
2 Principle ... 4
3 Reagents and Materials ... 4
4 Instruments and Equipment ... 5
5 Analytical Procedures ... 6
6 Expression of Analysis Results ... 8
7 Precision ... 9
8 Others ... 9
Method II - Inductively Coupled Plasma Mass Spectrometry ... 9
Appendix A Microwave Digestion Temperature Rise Program and Instrument
Reference Conditions of Graphite Furnace Atomic Absorption Spectrometry ... 10
National Food Safety Standard - Determination of Cadmium
in Foods
1 Scope
This Standard specifies the method for the determination of cadmium in foods by graphite
furnace atomic absorption spectrometry and inductively coupled plasma mass spectrometry.
This Standard is applicable to the determination of cadmium in foods.
Method I - Graphite Furnace Atomic Absorption
Spectrometry
2 Principle
After the specimen is digested, atomize it in a graphite furnace, at 228.8 nm, determine the
absorbance. Within a certain concentration range, the absorbance value of cadmium is
proportional to the cadmium content. Conduct quantitative comparison with standard series
solutions.
3 Reagents and Materials
Unless it is otherwise specified, the reagents used in this Method are all excellent-grade pure,
and the water is Grade-2 water specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Perchloric acid (HClO4).
3.1.3 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.4 Palladium nitrate [Pd(NO3)2].
3.2 Preparation of Reagents
3.2.1 Nitric acid solution (5 + 95): measure-take 50 mL of nitric acid, slowly add it to 950 mL
of water and evenly mix it.
3.2.2 Nitric acid solution (1 + 9): measure-take 50 mL of nitric acid, slowly add it to 450 mL of
water and evenly mix it.
3.2.3 Ammonium dihydrogen phosphate - palladium nitrate mixed solution: weigh-take 0.02 g
of palladium nitrate, add a small amount of nitric acid solution (1 + 9) to dissolve it, then, add
2 g of ammonium dihydrogen phosphate. After dissolving, use nitric acid solution (5 + 95) to
reach a constant volume of 100 mL, and evenly mix it.
3.3 Reference Material
Cadmium chloride (CdCl2 2.5H2O, CAS No.: 7790-78-5): purity > 99.99%, or a standard
substance certified by the state and awarded a reference material certificate.
3.4 Preparation of Standard Solutions
3.4.1 Cadmium standard stock solution (100 mg/L): accurately weigh-take 0.2032 g of
cadmium chloride, use a small amount of nitric acid solution (1 + 9) to dissolve it, transfer it
into a 1,000 mL volumetric flask. Add water to the scale and evenly mix it. The mass
concentration of cadmium in this solution is 100 mg/L.
3.4.2 Cadmium standard intermediate solution (100 g/L): accurately draw 1.00 mL of
cadmium standard stock solution (100 mg/L) into a 10 mL volumetric flask, add nitric acid
solution (5 + 95) to the scale, and evenly mix it. Then, accurately draw 1.00 mL of the above-
mentioned solution into a 100 mL volumetric flask, add nitric acid solution (5 + 95) to the scale,
and evenly mix it. The mass concentration of cadmium in this solution is 100 g/L.
3.4.3 Cadmium standard series of working solutions: respectively and accurately draw 0 mL,
0.200 mL, 0.500 mL, 1.00 mL, 2.00 mL and 4.00 mL of cadmium standard intermediate
solution (100 g/L) into a 100 mL volumetric flask. Add nitric acid solution (5 + 95) to the
scale, and evenly mix it. The mass concentration of cadmium in this series of solutions is 0
g/L, 0.200 g/L, 0.500 g/L, 1.00 g/L, 2.00 g/L and 4.00 g/L. Prepare them right before
use.
NOTE: the mass concentration of cadmium in the standard series of solutions can be determined
in accordance with the sensitivity of the instrument and the actual cadmium content in the
sample.
4 Instruments and Equipment
NOTE: all glassware and polytetrafluoroethylene digestion inner tanks need to be soaked in nitric
acid solution (1 + 5) overnight, repeatedly rinsed with tap water, and finally, thoroughly
rinsed with water.
4.1 Atomic absorption spectrometer: equipped with graphite furnace atomizer and cadmium
hollow cathode lamp.
4.2 Electronic balance: with a division value of 0.1 mg and 1 mg.
accurately transfer-take or weigh-take 0.500 mL (g) ~ 5.00 mL (g) (accurate to 0.001 g) into a
digestion tube with scale. For samples containing ethanol or carbon dioxide, firstly heat them
at a low temperature to remove ethanol or carbon dioxide, add 10 mL of nitric acid and 0.5 mL
of perchloric acid, and digest on an adjustable electric furnace (reference conditions: at 120 C,
maintain for 0.5 h ~ 1 h, raise to 180 C, maintain for 2 h ~ 4 h, raise to 200 C ~ 220 C). If
the digestion solution is brown, after cooling, add a small amount of nitric acid and digest it,
until it emits white smoke, and the digestion solution turns colorless, transparent or slightly
yellow. Drive acid to about 1 mL, take out the digestion tube, cool it and use water to reach a
constant volume of 10 mL or 25 mL, evenly mix it and reserve it for later use. Meanwhile,
conduct a blank test. Alternatively, a conical flask can also be used; on an adjustable electric
heating plate, in accordance with the above-mentioned operation method, perform wet digestion.
5.2.1.2 Microwave digestion method
For solid specimens, weigh-take 0.2 g ~ 0.5 g (accurate to 0.001 g; for samples containing
relatively high-water content, the sampling size can be appropriately increased to 1 g). For
liquid specimens, accurately transfer-take or weigh-take 0.500 mL (g) ~ 3.00 mL (g) (accurate
to 0.001 g) into a microwave digestion tank. For samples containing ethanol or carbon dioxide,
firstly heat them at a low temperature to remove ethanol or carbon dioxide, add 5 mL ~ 10 mL
of nitric acid, in accordance with the operation procedures of microwave digestion, digest the
specimen. For the digestion conditions, refer to Table A.1 in Appendix A. When necessary, after
adding acid, cover and let it stand for 1 h or overnight, then, in accordance with the operation
procedures of microwave digestion, digest the specimen. After cooling, take out the digestion
tank; at 140 C ~ 160 C, drive acid to about 1 mL. After the digestion tank cools, transfer the
digestion solution into a 10 mL of 25 mL volumetric flask. Use a small amount of water to wash
the digestion tank 2 ~ 3 times, combine the washing liquid in the volumetric flask and use water
to reach a constant volume to the scale; evenly mix it and reserve it for later use. Meanwhile,
conduct a blank test.
5.2.1.3 Pressure tank digestion method
For solid specimens, weigh-take 0.2 g ~ 1 g (accurate to 0.001 g; for samples containing
relatively high-water content, the sampling size can be appropriately increased to 2 g). For
liquid specimens, accurately transfer-take or weigh-take 0.500 mL (g) ~ 5.00 mL (g) (accurate
to 0.001 g) into a digestion inner tank. For samples containing ethanol or carbon dioxide, firstly
heat them at a low temperature to remove ethanol or carbon dioxide and add 5 mL ~ 10 mL of
nitric acid. Properly put on the inner cover, tighten the stainless-steel jacket, put it into a
constant-temperature drying oven; at 140 C ~ 160 C, maintain for 4 h ~ 5 h. When necessary,
after adding acid, cover and let it stand for 1 h or overnight, then, tighten the stainless-steel
jacket and put it into a constant-temperature drying oven to digest the specimen. After cooling,
slowly unscrew the stainless-steel jacket, take out the digestion inner tank; at 140 C ~ 160 C,
drive acid to about 1 mL. After cooling, transfer the digestion solution to a 10 mL or 25 mL
volumetric flask, use a small amount of water to wash the inner tank and inner cover for 2 ~ 3
times, combine the washing liquid in the volumetric flask and use water to reach a constant
volume to the scale; evenly mix it and reserve it for later use. Meanwhile, conduct a blank test.
5.3 Reference Conditions of Instruments
See Table A.2 for instrument operating conditions.
5.4 Drawing of Standard Curve
In accordance with the mass concentration from low to high, respectively take 10 L of the
standard series of solutions and 5 L of the ammonium dihydrogen phosphate - palladium
nitrate mixed solution (select the optimal sample injection volume in accordance with the
instrument used), meanwhile, inject it into the graphite tube. After atomization, determine the
absorbance value, and by taking the mass concentration as the x-coordinate and the absorbance
value as the y-coordinate, draw a standard curve.
5.5 Determination of Specimen Solution
Under the same test conditions as the standard curve, draw 10 L of blank solution or specimen
digestion solution, and 5 L of the ammonium dihydrogen phosphate - palladium nitrate mixed
solution (select the optimal sample injection volume in accordance with the instrument used),
meanwhile, inject it into the graphite tube. After atomization, determine the absorbance value.
In accordance with the standard curve, obtain the mass concentration of cadmium in the solution
to be tested. If the determination result is beyond the range of the standard curve, use nitric acid
solution (5 + 95) to dilute it, then, perform the determination.
6 Expression of Analysis Results
The content of cadmium in the specimen is calculated in accordance with Formula (1).
Where,
X---the cadmium content in the specimen, expressed in (mg/kg) or (mg/L);
ρ---the mass concentration of cadmium in the specimen digestion solution, expressed in (g/L);
ρ0---the mass concentration of cadmium in the blank solution, expressed in (g/L);
f---dilution factor;
V---the constant volume of the specimen digestion solution, expressed in (mL);
m---the mass or volume of the specimen, expressed in (g) or (mL);
1,000---conversion factor.
When the cadmium content is 0.1 mg/kg (mg/L), the calculation results shall retain 3
significant figures. When the cadmium content is < 0.1 mg/kg (mg/L), the calculation results
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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