GB 5009.268-2016

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GB 5009.268-2016	English	95	Add to Cart	0--9 seconds. Auto-delivery	National food safety standard - Determination of calcium, iron, zinc, sodium, potassium, magnesium, copper and manganese in foods for infants and young children, milk and milk products	GB 5009.268-2016	Valid	GB 5009.268-2016

GB 5009.268-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard –
Determination of multi-elements in foods
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of the PRC;
State Food and Drug Administration.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Principle... 4 
3 Reagents and materials ... 4 
4 Instruments and equipment ... 6 
5 Analytical procedures ... 6 
6 Expression of analysis results ... 8 
7 Precision... 10 
8 Others ... 10 
9 Principle... 11 
10 Reagents and materials... 11 
11 Instruments and equipment ... 12 
12 Analytical procedures ... 12 
13 Expression of analytical results ... 14 
14 Precision ... 14 
15 Others ... 14 
Appendix A Mass concentration of standard solution series ... 16 
Appendix B Instrument reference conditions ... 18 
National food safety standard –
Determination of multi-elements in foods
1 Scope
This standard specifies inductively coupled plasma mass spectrometry (ICP-
MS) and inductively coupled plasma emission spectrometry (ICP-OES) for the
determination of multi-element in foods.
The method I is applicable to the determination of boron, sodium, magnesium,
aluminum, potassium, calcium, titanium, vanadium, chromium, manganese,
iron, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, tin,
antimony, mercury, thallium, and lead in foods; the method II is applicable to the
determination of aluminum, boron, barium, calcium, copper, iron, potassium,
magnesium, manganese, sodium, nickel, phosphorus, strontium, titanium,
vanadium, and zinc in foods.
Method I. Inductively coupled plasma mass spectrometry (ICP-MS)
2 Principle
The sample is digested and determined by inductively coupled plasma mass
spectrometry. It is subject to qualitative determination by the specific mass
number of element (mass/charge ratio, m/z). The quantitative analysis is
performed by the use of external standard method and by that the ratio between
the strength ratio of the mass spectrometry signal of the tested element to the
internal standard element mass spectrometry signal and the concentration of
the element to be determined.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are all guaranteed
grade, the water is a level 1 water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3). Guaranteed grade or higher purity.
3.1.2 Argon (Ar). Argon (≥ 99.995%) or liquid argon.
3.1.3 Helium (He). Helium (≥ 99.995%).
internal standard use solution of appropriate concentration, the concentration
of the internal standard use solution is as shown in A.2.
Note. The internal standard solution can either be manually added
quantitatively in the preparation of mixed standard working solution and sample
digestion solution, or be added online by the instrument.
4 Instruments and equipment
4.1 Inductively coupled plasma mass spectrometry (ICP-MS).
4.2 Balance. The sensitivity is 0.1 mg and 1 mg.
4.3 Microwave digestion instrument. Equipped with PTFE digestion inner tank.
4.4 Pressure digestion tank. Equipped with PTFE digestion inner tank.
4.5 Constant temperature drying oven.
4.6 Temperature control electric heating plate.
4.7 Ultrasonic water bath.
4.8 Sample crushing equipment. Homogenizer, high-speed crusher.
5 Analytical procedures
5.1 Specimen preparation
5.1.1 Solid sample
5.1.1.1 Dry sample
For the samples of low moisture content such as beans, cereals, fungi, tea,
dried fruits, baked goods, etc., TAKE the edible parts, if necessary, USE high-
speed crusher to crush it evenly; for the uniform powder sample such as solid
dairy products, protein powder, flour, etc., SHAKE it uniformly.
5.1.1.2 Fresh sample
For the samples of high moisture content such as vegetables, fruits, and aquatic
products, it shall be washed clean when necessary, dried naturally, and the
edible parts shall be homogenized uniformly; for such samples as meat, eggs,
etc., the edible parts shall be homogenized uniformly.
5.1.1.3 Frozen and canned food
the digestion tank on the temperature control electric hot plate or in the
ultrasonic bath, HEAT it at 100 °C for 30 min or PERFORM ultrasonic degassing
for 2 min ~ 5 min, USE water to make the volume reach to 25 mL or 50 mL, MIX
it uniformly to prepare for use, meanwhile PERFORM blank test.
5.3 Instrument reference conditions
5.3.1 Instrument operating conditions. Instrument operating conditions are
shown in Table B.2; elemental analysis modes are shown in Table B.3.
Note. For instruments that do not have a suitable interference elimination mode,
the interference correction equation shall be used to correct the measurement
results. The interference correction equations for lead, cadmium, arsenic,
molybdenum, selenium, vanadium, and other elements are given in Table B.4.
5.3.2 Determination reference conditions. After tuning the instrument to meet
the measurement requirements, EDIT the measurement method and SELECT
the appropriate internal standard element based on the nature of the element
to be measured. SEE Table B.5 for m/z of the test element and the internal
standard element.
5.4 Production of standard curves
INJECT the mixed standard solution into an inductively coupled plasma mass
spectrometer, to measure the signal response values of the test element and
the internal standard element. USE the concentration of the test element as the
abscissa and the ratio of the response signal value of the test element to the
selected internal standard element as the ordinate, to draw a standard curve.
5.5 Determination of specimen solution
Respectively INJECT the blank solution and the specimen solution into an
inductively coupled plasma mass spectrometer, to measure the signal response
values of the test element and the internal standard element, and to obtain the
concentration of the test element in the digestion solution in accordance with
the standard curve.
6 Expression of analysis results
6.1 Calculation of low-content test elements
The content of the low-content test element in the specimen is calculated in
accordance with the formula (1).
12.2.1 Microwave digestion method
Same as 5.2.1.
12.2.2 Pressure tank digestion method
Same as 5.2.2.
12.2.3 Wet digestion method
Accurately WEIGH 0.5 g ~ 5 g (accurate to 0.001 g) or accurately PIPETTE
2.00 mL ~ 10.0 mL of specimen in glass or PTFE digestion vessel; for the
sample containing ethanol or carbon dioxide, first HEAT it on a hot plate at low
temperature to remove ethanol or carbon dioxide, ADD 10 mL of nitric acid-
perchloric acid (10 + 1) mixed solution, MAKE it subject to digestion on an
electric hot plate or graphite digestion device, if the digestion solution becomes
brown and black in the digestion process, it may add a small amount of mixed
acid appropriately, until white smoke is produced, the digestion solution is
colorless, transparent or slightly yellow, COOL it, USE water to make its volume
reach to 25 mL or 50 mL, MIX it uniformly to prepare for use; meanwhile
PERFORM blank test.
12.2.4 Dry digestion method
Accurately WEIGH 1 g ~ 5 g (accurate to 0.01 g) or accurately PIPETTE 10.0
mL ~ 15.0 mL of specimen in the crucible, PLACE it in 500 °C ~ 550 °C muffle
furnace to ash it for 5 h ~ 8 h, COOL it down. If the ash is not complete, there
will be black charcoal particles, then ADD a little nitric acid to wet it after cooling,
after drying it on an electric hot plate, TRANSFER it into the muffle furnace to
continue ash it to white ash, COOL it down and TAKE it out, ADD 10 mL of nitric
acid solution to dissolve it, USE water to make its volume reach to 25 mL or 50
mL, MIX it uniformly to prepare for use; meanwhile PERFORM blank test.
12.3 Instrument reference conditions
OPTIMIZE the operating conditions of the instrument, so that the sensitivity of
the element to be determined meets the analysis requirements. EDIT the
determination method and SELECT the appropriate analysis spectral line of
each test element, the instrument operating conditions are as shown in B.3.1,
the recommended analysis spectral line of the test element is as shown in Table
B.6.
12.4 Production of standard curves
INJECT the standard series working solution into an inductively coupled plasma
emission spectrometer, to measure the strength signal response value of the
analytical spectral line of the test element. USE the concentration of the test