GB 5009.137-2016 PDF in English
GB 5009.137-2016 (GB5009.137-2016) PDF English
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National food safety standard -- Determination of antimony in foods
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GB/T 5009.137-2003 | English | 239 |
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Determination of antimony in foods
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Standards related to (historical): GB 5009.137-2016
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GB 5009.137-2016: PDF in English GB 5009.137-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Antimony in Foods
ISSUED ON. DECEMBER 23, 2016
IMPLEMENTED ON. JUNE 23, 2017
Issued by. National Health and Family Planning Commission of the
People’s Republic of China;
China Food and Drug Administration.
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Table of Contents
Foreword ... 3
1 Application Scope ... 4
2 Principle ... 4
3 Reagents and Materials ... 4
4 Apparatus ... 6
5 Analytical Procedures ... 6
6 Expression of Analytical Results ... 8
7 Precision ... 9
8 Others ... 9
Annex A Temperature Programming of Microwave Digestion ... 10
National Food Safety Standard -
Determination of Antimony in Foods
1 Application Scope
This Standard specifies the hydride atomic fluorescence spectrometric method for the
determination of antimony in foods.
This Standard applies to the determination of antimony in foods.
2 Principle
After the sample is digested through acid and heating, in the acidic medium, antimony
in the sample reacts with sodium borohydride or potassium borohydride to produce
volatile antimony hydride; use argon as the carrier gas to lead antimony hydride into
an electric heating quartz atomizer for atomization; under the exposure to antimony
hollow cathode lamp, the ground-state antimony atom is excited to the upper-state,
and then return to the ground-state from the upper-state; it emits fluorescence of a
characteristic wavelength whose fluorescent strength is in direct proportion to
antimony content; and quantitate in accordance with the standard series.
3 Reagents and Materials
Unless specified otherwise, all reagents used in this method are guaranteed reagents;
and all water is grade-2 water specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Hydrogen peroxide (H2O2).
3.1.3 Hydrochloric acid (HCl).
3.1.4 Sulfuric acid (H2SO4).
3.1.5 Perchloric acid (HClO4).
3.1.6 Thiocarbamide [(NH2)2CS]. analytically pure.
3.1.7 Potassium iodide (KI). analytically pure.
3.1.8 Ascorbic acid (C6H8O6). analytically pure.
3.1.9 Potassium borohydride (KBH4) or sodium borohydride (NaBH4).
3.1.10 Potassium hydroxide (KOH) or sodium hydroxide (NaOH).
3.2 Preparation of reagents
3.2.1 Nitric acid-perchloric acid mixed acid (10 + 1). measure 500 ml of nitric acid
and 50 ml of perchloric acid; and mix up.
3.2.2 Hydrochloric acid (1 + 9). measure 50 ml of hydrochloric acid; add into 450 ml
of water; and mix up.
3.2.3 Thiocarbamide-ascorbic acid solution. weigh 10 g of thiocarbamide and 10 g of
ascorbic acid; dissolve into 100 ml of water; and mix up.
3.2.4 Thiocarbamide-potassium iodide solution. weigh 2 g of thiocarbamide and 10
g of potassium iodide; dissolve in 100 ml of water; and mix up.
3.2.5 Potassium hydroxide solution (2 g/l). weigh 1 g of potassium hydroxide;
dissolve in 500 ml of water; mix up; and prepare it immediately before use. Potassium
hydroxide in the solution may be replaced with sodium hydroxide.
3.2.6 Potassium borohydride alkali solution (20 g/l). weigh 10 g of potassium
borohydride; dissolve in 500 ml of potassium hydroxide solution (2 g/l); mix up; and
prepare immediately before preparation. Potassium borohydride in the solution may
also be replaced with sodium borohydride of an equal molar ratio.
3.3 Standard substance
Antimony standard solution. 1 000 mg/l. Or an antimony standard solution of a certain
concentration which has been certified by the state and granted the certificate of
standard substance.
3.4 Preparation of standard solutions
3.4.1 Antimony standard intermediate solution (100 mg/l). accurately absorb 1 ml of
antimony standard solution (1 000 mg/l) to pour into a 10 ml volumetric flask; add water
dropwise to volume; and mix up.
3.4.2 Antimony standard working solution (1.00 mg/l). accurately absorb 1 ml of
antimony standard intermediate solution (100 mg/l) to pour into a 100 ml volumetric
flask; add water dropwise to volume; and mix up.
3.4.3 Antimony standard serial solutions. accurately absorb 0 ml, 0.100 ml, 0.200 ml,
0.400 ml, 1.00 ml and 2.00 ml of antimony standard working solution to pour into 100
ml volumetric flasks respectively; after adding a small amount of water for dilution, add
10 ml of hydrochloric acid solution (1 + 9) and 10 ml of thiocarbamide-potassium iodide
solution or thiocarbamide-ascorbic acid solution; add water dropwise to volume; and
mix up. The mass concentrations of the antimony standard serial solutions are 0 μg/l,
Adjust the instrument to the optimum conditions of performance with the reference
conditions for the instrument. photomultiplier voltage, 300 V; the hollow cathode lamp
current, 60 mA; the atomizer height, 8 mm; the carrier gas flow, 300 ml/min. Adjust to
the optimum conditions in accordance with the performance of each instrument.
5.4 Plotting of standard curves
Set the optimum conditions of the instrument; raise the furnace temperature to the
required temperature; and start measurement after stabilizing for 20 min ~ 30 min. Use
the hydrochloric acid (5%) as the carrier, potassium borohydride alkali solution (20 g/l)
as the reducer; continuously use the standard serial solutions introduced using a zero
tube; after the readings become stable, lead the antimony standard serial solution into
the instrument from higher concentration to lower concentration; and determine the
fluorescence value. Plot the standard curve using the mass concentration of the
antimony standard serial solutions as the abscissa and the corresponding
fluorescence value as the ordinate.
NOTE If an automatic sample introduction device is available, the programmed automatic
dilution may also be used for the preparation of standard series.
5.5 Determination of sample solution
Under the same test conditions as those for the determination of the standard solution
series, lead the blank solution and test solution into the instrument respectively;
determine the fluorescence values; and compare with those of the standard series for
quantitation.
6 Expression of Analytical Results
The content of antimony in samples is calculated in accordance with Formula (1).
where,
X--the content of antimony in sample, in mg/kg or mg/l;
ρ--the mass concentration of antimony in sample solution, in μg/l;
ρ0--the mass concentration of antimony in blank solution, in in μg/l;
V--the constant volume of sample digestive juice, in ml;
m--the weight or transferred volume of sample, in g or ml;
1 000--the conversion coefficient.
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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