GB 5009.241-2017 PDF in English
GB 5009.241-2017 (GB5009.241-2017) PDF English
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Food safety national standard -- Determination of magnesium in food
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Standards related to (historical): GB 5009.241-2017
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GB 5009.241-2017: PDF in English GB 5009.241-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Magnesium in Food
ISSUED ON. APRIL 06, 2017
IMPLEMENTED ON. OCTOBER 06, 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 &
immediately delivered to your EMAIL address in 0~60 minutes.
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 ... 8
7 Precision ... 8
8 Others ... 8
Appendix A Microwave Digestion and Temperature-Rise Program ... 10
Foreword
This Standard replaced the determination of magnesium in the following standards
such as GB/T 5009.90-2003 Determination of iron, Magnesium and Manganese in
Foods, GB/T 9695.21-2008 Meat and Meat Products - Determination of Magnesium,
GB 5413.21-2010 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/T 23375-2009 Determination of
Copper, Iron, Zinc, Calcium, Magnesium and Phosphorus Content in Vegetables and
Derived Products, GB/T 14609-2008 Inspection of Grain and Oils - Determination of
Copper, Iron, Manganese, Zinc, Calcium, Magnesium In Cereals and Derived Products
by Atomic Absorption and Flame Spectrophotometry, GB/T 18932.12-2002 Method for
the Determination of Potassium, Sodium, Calcium, Magnesium, Zine, Iron, Copper,
Manganese, Chromium, Lead, Cadmium Contents in Honey - Atomic Absorption
Spectrometry, NY 82.19-1988 Determination of Calcium and Magnesium in Fruit Juice.
Compared with GB/T 5009.90-2003, this Standard has the major changes as follows.
--- Modify the standard name into “National Food Safety Standard – Determination
of Magnesium in Food”;
--- Adjust the sample pre-treatment into wet digestion, microwave digestion, dry
ashing and pressure tank digestion;
--- Retain the flame atomic absorption spectrometry, and delete titration for sample
determination;
--- Add inductively coupled plasma emission spectrometry as the second method;
--- Add inductively coupled plasma mass spectrometry as the third method.
National Food Safety Standard -
Determination of Magnesium in Food
1 Scope
This Standard specifies use flame atomic absorption spectrometry, inductively coupled
plasma emission spectrometry, and inductively coupled plasma mass spectrometry to
determine the magnesium in food.
This Standard is applicable to the determination of magnesium in various foods.
The First Method of Flame Atomic Absorption Spectrometry
2 Principle
After digestion, the sample was flame atomized, then measure the absorbance at
285.2nm. In a certain concentration range, the magnesium absorbance value is
proportional to the magnesium content; compare with the standard series and then
quantify.
3 Reagents and Materials
Unless otherwise is specified, the reagents used in this method shall be guarantee
reagent; while water used in this method shall be Class-II water stipulated in GB/T
6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Perchloric acid (HClO4).
3.13 Hydrochloric acid (HCl).
3.2 Reagents preparation
3.2.1 Nitric acid solution (5+95). take 50mL of nitric acid; pour into 950mL of water;
mix evenly.
nitric acid; then digest the specimen as per the microwave digestion operation steps;
the digestion conditions can refer to Appendix A. After cooling off, take out the digestion
tank, put on the electric hot plate at 140°C~180°C to catch acid to 0.5mL ~ 1mL. After
the digestion tank is allowed to cool off, transfer the digestion solution into 25mL
volumetric flask; use a small amount of water to wash the digestion tank for 2~3 times;
combine the washing liquid into the volumetric flask; then use water to make constant
volume to the scale; mix evenly for spare-use. Meanwhile, do the blank teste of
reagents.
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; place into the constant-
temperature drying oven; maintain for 4h~5h at 140°C~160°C. Slowly loosen the outer
tank after cooling; take out the digestion inner tank; place onto the adjustable electric
hot plate, then expel the acid to about 1mL at 140°C~160°C. After cooling, transfer the
digestion solution to the 25mL volumetric flask; use a small amount of water to wash
the inner tank and inner cap for 2~3 times; combine the washing liquid into the
volumetric flask; and use water to make constant volume to the scale, mix evenly for
spare-use. Meanwhile do the blank test.
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 the crucible; slowly heat the crucible onto the
electric hot plate; carbonize with slight fire to no longer smoke. After carbonizing, place
the specimen into the muffle furnace; ashing for 4h at 550°C. If the specimen after
ashing has the black participles; cool off the crucible to the room temperature; add
small amount of nitric acid (5+95) to moisten the residue; after evaporating on the
electric hot plate with small fire, place it onto the muffle furnace to continue ashing at
550°C till specimen becomes lime-shape. After cooling off in the muffle furnace, take
it out; cool off to the room temperature; use 2.5mL of nitric acid (1+1) to dissolve; use
small amount of water to wash crucible for 2~3 times; combine the washing liquid into
the volumetric flask; make constant volume to 25mL; mix evenly for spare-use.
Meanwhile, do the blank test.
5.3 Determination
5.3.1 Instrument reference conditions
According to the performance of their instruments adjusted to the best condition,
reference conditions. air-acetylene flame, wavelength 285.2mm, slit 0.2nm, lamp
current 5mA~15mA.
5.3.2 Drawing of standard curve
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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