GB 5009.138-2024_English: PDF (GB5009.138-2024)
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National food safety standards--Determination of nickel in food
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GB 5009.138-2024
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| GB 5009.138-2017 | English | 85 |
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Food safety national standard -- Determination of nickel in food
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GB 5009.138-2017
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| GB/T 5009.138-2003 | English | 279 |
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Determination of nickel in foods
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GB/T 5009.138-2003
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| Standard ID | GB 5009.138-2024 (GB5009.138-2024) | | Description (Translated English) | National food safety standards--Determination of nickel in food | | Sector / Industry | National Standard | | Word Count Estimation | 10,150 | | Date of Issue | 2024/2/8 | | Standard ID | GB 5009.138-2017 (GB5009.138-2017) | | Description (Translated English) | Food safety national standard -- Determination of nickel in food | | Sector / Industry | National Standard | | Classification of Chinese Standard | X09 | | Word Count Estimation | 9,916 | | Date of Issue | 2017-04-06 | | Date of Implementation | 2017-09-17 | | Older Standard (superseded by this standard) | GB/T 5009.138-2003 | | Regulation (derived from) | State Health and Family Planning Commission Notice No. 5 of 2017 | | Standard ID | GB/T 5009.138-2003 (GB/T5009.138-2003) | | Description (Translated English) | Determination of nickel in foods | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | C53 | | Classification of International Standard | 67.040 | | Word Count Estimation | 7,750 | | Date of Issue | 2003-08-11 | | Date of Implementation | 2004-01-01 | | Older Standard (superseded by this standard) | GB/T 16343-1996 | | Drafting Organization | Zhejiang Academy of Medical Sciences | | Administrative Organization | People's Republic of China Ministry of Health | | Proposing organization | Ministry of Health of the People Republic of China | | Issuing agency(ies) | The People Republic of China Ministry of Health, China National Standardization Management Committee | | Summary | This standard specifies: graphite furnace atomic absorption spectrophotometry foods nickel. This standard applies to: all kinds of foods Nickel Determination. |
GB 5009.138-2024
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard - Determination of nickel in
food
ISSUED ON: FEBRUARY 08, 2024
IMPLEMENTED ON: AUGUST 08, 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
2 Principle ... 4
3 Reagents and materials ... 4
4 Instruments and apparatuses ... 5
5 Analysis steps ... 6
6 Expression of analysis results ... 8
7 Precision ... 9
8 Others ... 9
9 Detection limit and quantification limit ... 10
Appendix A Microware digestion reference heating program ... 11
Appendix B Graphite furnace reference heating program ... 12
National food safety standard - Determination of nickel in
food
1 Scope
This Standard specifies the methods for the determination of nickel in food by graphite
furnace atomic absorption spectrometry, inductively coupled plasma mass spectrometry
and inductively coupled plasma emission spectrometry.
This Standard applies to the determination of nickel in food.
Method I – Graphite furnace atomic absorption spectrometry
2 Principle
After digestion treatment, the sample is atomized in a graphite furnace and the
absorbance is measured at 232.0 nm. Within a certain concentration range, the
absorbance value of nickel is proportional to the nickel content, and the external
standard method is used for quantification.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are guaranteed reagents, and
the water is grade-II water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Perchloric acid (HClO4).
3.1.3 Palladium nitrate [Pd(NO3)2].
3.1.4 Ammonium dihydrogen phosphate (NH4H2PO4).
3.2 Preparation of reagents
3.2.1 Nitric acid solution (5+95): Measure 50 mL of nitric acid; slowly add it to 950
mL of water; mix well.
3.2.2 Nitric acid solution (1+1): Measure 500 mL of nitric acid; slowly add it to 500
mL of water; mix well.
3.2.3 Nitric acid solution (1+5): Measure 100 mL of nitric acid; slowly add it to 500
mL of water; mix well.
3.2.4 Ammonium dihydrogen phosphate-palladium nitrate solution: Weigh 0.02 g of
palladium nitrate; add a small amount of nitric acid solution (1+1) to dissolve it; then,
add 2 g of ammonium dihydrogen phosphate; after dissolution, use nitric acid solution
(1+1) to adjust the volume to 100 mL; mix well.
3.3 Standards
Metallic nickel (Ni, CAS number: 7440-02-0): purity >99.99%, or nickel standard
solution certified by the country and awarded a standard material certificate.
3.4 Preparation of standard solutions
3.4.1 Nickel standard stock solution (1 000 mg/L): Accurately weigh 1 g (accurate to
0.0001 g) of metallic nickel; add 30 mL of nitric acid solution (1+1); heat to dissolve;
transfer it to 1000 mL volumetric flask; add water to dilute to the mark; mix well.
Refrigerate this solution at 0 ℃ ~ 5 ℃; it is valid for 6 months.
3.4.2 Nickel standard intermediate solution (10.0 mg/L): Accurately draw 1.00 mL of
nickel standard stock solution (1 000 mg/L) into a 100 mL volumetric flask; use nitric
acid solution (5+95) to dilute it to the mark; mix well. Refrigerate this solution at 0 ℃
~ 5 ℃; it is valid for 1 month.
3.4.3 Nickel standard solution (1.00 mg/L): Accurately draw 10.00 mL of nickel
standard intermediate solution (10.0 mg/L) into a 100 mL volumetric flask; use nitric
acid solution (5+95) to adjust the volume to the mark; mix well. Refrigerate this
solution at 0 ℃ ~ 5 ℃; it is valid for 1 month.
3.4.4 Nickel standard series solution: Respectively take 0 mL, 0.25 mL, 0.50 mL, 1.00
mL, 2.00 mL and 2.50 mL of nickel standard solution (1.00 mg/L) into the 100 mL
volumetric flasks; add nitric acid solution (5+95) to the mark; mix well. The mass
concentrations of this nickel standard series solution are 0 μg/L, 2.50 μg/L, 5.0 μg/L,
10.0 μg/L, 20.0 μg/L and 25.0 μg/L, respectively. Prepare when necessary.
Note: The mass concentration of nickel in the standard series solution can be
determined based on the sensitivity of the instrument, the actual nickel content
in the sample, and different instrument models.
4 Instruments and apparatuses
Note: All glassware, polytetrafluoroethylene digestion inner tank and inner cover need
to be soaked in nitric acid solution (1+5) overnight, rinsed repeatedly with tap
water, and finally rinsed with water.
Mix well.
5.2 Sample digestion
5.2.1 Wet digestion method
Weigh 0.5 g ~ 2 g (accurate to 0.001 g) of the solid sample or accurately transfer 0.50
mL ~ 3.00 mL of the liquid sample into a graduated digestion tube. Heat samples
containing ethanol or carbon dioxide first at low temperature on an electric hot plate to
remove the ethanol or carbon dioxide. Add 10 mL of nitric acid and 0.5 mL of perchloric
acid; put a few glass beads; digest it on an adjustable electric furnace (reference
conditions: 120 °C for 0.5 h ~ 1 h; rise to 180 °C for 2 h ~ 4 h, rise to 200 °C ~ 220 ℃).
If the digestive juice is brown, add a small amount of nitric acid and digest until white
smoke is emitted and the digestive juice is colorless, transparent or slightly yellow.
Remove acid to nearly 1 mL; stop digestion; cool and add water to dilute to 10 mL or
25 mL; mix well and set aside. Do a reagent blank test at the same time. Alternatively,
use an Erlenmeyer flask and perform wet digestion on an adjustable electric heating
plate according to the above operation methods.
5.2.2 Microwave digestion
Weigh 0.2 g ~ 0.5 g (accurate to 0.001 g) of the solid sample or accurately transfer 0.50
mL ~ 2.00 mL of the liquid sample into the microwave digestion tank. For samples
containing ethanol or carbon dioxide, first heat at low temperature on an electric hot
plate to remove the ethanol or carbon dioxide; add 5 mL ~ 10 mL of nitric acid; digest
the sample according to the operating steps of microwave digestion. For digestion
conditions, refer to Table A.1 of Appendix A. After cooling, take out the digestion tank;
reduce the acid to about 1 mL at 140 °C ~ 160 °C on the electric heating plate. After the
digestion tank cools off, transfer the digestive juice to a 10 mL or 25 mL volumetric
flask; use a small amount of water to wash the digestion tank 2 ~ 3 times; combine the
cleaning mixture in the volumetric flask and use water to adjust the volume to the mark;
mix well and set aside. Do a reagent blank test at the same time.
5.2.3 Pressure tank digestion
Weigh 0.2 g ~ 1 g (accurate to 0.001 g) of the solid sample or accurately transfer 0.50
mL ~ 5.00 mL of the liquid sample into the digestion inner tank. For samples containing
ethanol or carbon dioxide, first heat at low temperature on an electric hot plate to
remove the ethanol or carbon dioxide; add 5 mL of nitric acid. Close the inner cover;
screw the stainless-steel jacket tightly; put it in a constant-temperature drying oven;
keep it at 140 °C ~ 160 °C for 4 h ~ 5 h. After cooling, slowly unscrew the outer tank,
take out the digestion inner tank, and place it on an adjustable electric hot plate to reduce
acid to about 1 mL at 140 ℃ ~ 160 ℃. 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 2 ~ 3 times; combine the cleaning mixture in the volumetric flask; use
Where:
X – the nickel content in the sample, in milligrams per kilogram (mg/kg) or milligrams
per liter (mg/L);
ρ – the mass concentration of nickel in the sample solution, in micrograms per liter
(μg/L);
f – dilution factor;
ρ0 – the mass concentration of nickel in the blank solution, in micrograms per liter
(μg/L);
V – the constant volume of the sample digestion solution, in milliliters (mL);
m – the weighing amount or pipetting volume of the sample, in grams (g) or milliliters
(mL);
1 000 – Conversion factor.
When the nickel content is ≥1.00 mg/kg (or mg/L), retain 3 significant figures for the
calculation result; when the nickel content is < 1.00 mg/kg (or mg/L), retain 2 significant
figures for the calculation result.
7 Precision
When the nickel content in the sample is greater than 1 mg/kg (or mg/L), the absolute
difference between the two independent measurement results obtained under
repeatability conditions shall not exceed 10% of the arithmetic mean; when it is less
than or equal to 1 mg/kg (or mg/L) and greater than 0.1 mg/kg (or mg/L), the absolute
difference between two independent determination results obtained under repeatability
conditions shall not exceed 15% of the arithmetic mean; when it is less than or equal to
0.1 mg/kg (or mg/L), the absolute difference between two independent determination
results obtained under repeatability conditions shall not exceed 20% of the arithmetic
mean.
8 Others
When the sample volume is 0.5 g (or 0.5 mL) and the constant volume is 10 mL, the
detection limit of the method is 0.02 mg/kg (or 0.02 mg/L), and the quantitation limit
is 0.05 mg/kg (or 0.05 mg/ L).
Method II – Inductively coupled plasma mass spectrometry
......
GB 5009.138-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard
– Determination of Nickel in Food
ISSUED ON. APRIL 06, 2017
IMPLEMENTED ON. SEPTEMBER 17, 2017
Issued by. National Health and Family Planning Commission of PRC.;
China Food and Drug Administration.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Principle ... 4
3 Reagents and Materials ... 4
4 Instrument and Equipment ... 5
5 Analytical Procedures ... 6
6 Expression of Analytical Results ... 8
7 Precision ... 8
8 Others ... 8
Appendix A Recommended Temperature-Rise Procedures for Microwave
Digestion ... 9
Appendix B Recommended Temperature-Rise Procedures for Graphite
Furnace ... 10
National Food Safety Standard
– Determination of Nickel in Food
1 Scope
This Standard specifies using the graphite furnace atomic absorption spectrometry to
determine the nickel content in the food.
This Standard is applicable to determine the nickel content in various foods.
2 Principle
After the digestion of the sample, measure the absorbance at 232.0nm through the
atomization of the graphite furnace. In a certain concentration range, the nickel
absorbance value is proportional to the nickel content; quantify through the comparison
with the standard series.
3 Reagents and Materials
Unless otherwise specified, the reagents used in this method are guaranteed reagents;
while water is Class-II water specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Perchloric acid (HClO4).
3.1.3 Palladium nitrate [Pd(NO3)2].
3.1.4 Ammonium dihydrogen phosphate (NH4H2PO4).
3.2 Reagents preparation
3.2.1 Nitric acid solution (0.5mol/L). pipette 3.2mL of nitric acid; add water to dilute
to 100mL, mix evenly.
3.2.2 Nitric acid solution (1+1). weigh 500mL of nitric acid; mix with 500mL of water
evenly.
3.2.3 Ammonium dihydrogen phosphate – palladium nitrate solution. take 0.02g of
palladium nitrate; add small amount of nitric acid solution (1+1) by several times to
4.8 Muffle furnace.
5 Analytical Procedures
5.1 Specimen preparation
NOTE. during the sampling and specimen preparation period, the specimen contamination
shall be avoided.
5.1.1 Grains and beans samples
After removing the debris, crush the samples and store into the plastic bottles.
5.1.2 Vegetables, fruits, fish, meat and the like samples
Wash the samples with water, dry them; then take the edible part, and make into the
homogenate state, and store into the plastic bottles.
5.1.3 Drinks, wine, vinegar, soy sauce, edible vegetable oil, liquid milk and
other liquid samples
Shake the samples evenly.
5.2 Specimen digestion
5.2.1 Wet digestion
Take 0.2g~3g (accurate to 0.001g) of solid specimen or accurately pipette
0.500mL~5.00mL of liquid specimen into the digestion tube with scale; add 10mL of
nitric acid, 0.5mL of perchloric acid; digest on the adjustable electric hot furnace
(reference condition. 120°C/0.5h~1h, rise to 180°C/2h~4h, rise to 200°C~220°C). If
the digestive juice is tan, add small amount of nitric acid and digest till white smoke
appears; then digestive juice is colorless and transparent or slightly yellow; take out
the digestion tube; after cooling off, use water to make constant volume to 10mL, mix
evenly and for later-use. Meanwhile do the blank test of the reagent. The conical flask
can also be used; perform the wet digestion on the adjustable electric hot plate
according to the above-mentioned method.
5.2.2 Microwave digestion
Take 0.2g~0.8g (accurate to 0.001g) of solid specimen or accurately pipette
0.500mL~3.00mL of liquid specimen into the microwave digestion tank; add 5mL of
nitric acid; digest the specimen according to the microwave digestion procedures; the
digestion condition can refer to Appendix A. After cooling off, take out the digestion
tank; expel acid on the electric hot plate at 140°C~160°C to 1mL or so. After the
digestion tank is cooling off, transfer the digestive juice into the 10mL volumetric flask;
use small amount of water to wash and digest the tank for twice and three times;
combine the washing liquids into the volumetric flask; use water to make constant
volume to the scale; mix evenly for later-use. Meanwhile do the blank test of the
reagent.
5.2.3 Pressure tank digestion
Take 0.2g~1g (accurate to 0.001g) of solid specimen or accurately pipette
0.500mL~5.00mL of liquid specimen into the digestion inner tank; add 5mL of nitric
acid. Cover the inner cap, tighten the stainless-steel jacket; put into the constant
temperature oven; maintain for 4h~5h at 140°C~160°C. After cooling, slowly loosen
the outer tank; take out the digestion inner tank; expel acid on the adjustable electric
hot plate at 140°C~160°C to 1mL or so. After cooling off, transfer the digestive juice
into the 10mL volumetric flask; use small amount of water to wash the inner tank and
inner cap for twice ~ three times; combine the washing liquids into the volumetric flask,
use water to make constant volume to the scale. Meanwhile do the blank test of the
reagent.
5.2.4 Dry ashing
Take 0.5g~5g (accurate to 0.001g) of solid specimen or accurately pipette
0.500mL~10.0mL of liquid specimen into a crucible; heat with small fire and carbonize
to smokeless; transfer into the muffle furnace to ash for 3h~4h at 550°C. After cooling
off, take out; for the specimen that is not ashed completely, add several drops of nitric
acid; heat on small fire; carefully dry it; then transfer into the 550°C muffle furnace;
continue to ash for 1h~2h till the specimen becomes the white ash state; cooling off,
take out; dissolve by appropriate amount of nitric acid solution (1+1); then use water
to make constant volume to 10mL. Meanwhile do the blank test of the reagent.
5.3 Determination
5.3.1 Instrument reference conditions
Adjust the instrument to the optical state according to its performance. The reference
condition can refer to Appendix B.
5.3.2 Drawing of standard curve
Inject 10µL of nickel standard series solution and 5µL of ammonium dihydrogen
phosphate-palladium nitrate solution (the optical sample injection volume can be
determined according to the used instrument) into the graphite furnace at the same
time according to the order of mass concentration from low to high; after atomization,
measure the absorbance value; then draw the standard curve with mass concentration
as abscissa, and absorbance value as the ordinate.
5.3.3 Determination of specimen solution
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