GB 5009.17-2014 (GB 5009.17-2021 Newer Version) PDF English
GB 5009.17-2014 (GB5009.17-2014) PDF English
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Name of Chinese Standard | Status |
| GB 5009.17-2021 | English | 380 |
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Determination of total mercury and organic-mercury in foods
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| GB 5009.17-2014 | English | 85 |
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National Food Safety Standard -- Determination of total mercury and organic-mercury in food
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| GB/T 5009.17-2003 | English | 140 |
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Determination of total mercury and organic mercury in foods
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| GB/T 5009.17-1996 | English | 279 |
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Method for determination of total mercury in foods
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| GB 5009.17-1985 | English | 199 |
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Method for determination of total mercury in foods
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Newer version: GB 5009.17-2021 Standards related to (historical): GB 5009.17-2021
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GB 5009.17-2014: PDF in English GB 5009.17-2014
GB
NATIONAL STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard-Determination of total
mercury and organic-mercury in foods
ISSUED ON. SEPTEMBER 21, 2015
IMPLEMENTED ON. MARCH 21, 2016
Issued by. National Health and Family Planning Commission
Table of Contents
Foreword ... 4
1 Scope ... 5
Chapter I Determination of total mercury in foods ... 5
The first method Atomic fluorescence spectrometry ... 5
2 Principle... 5
3 Reagents and materials ... 5
4 Apparatus ... 7
5 Analysis procedures ... 7
6 Representation of analysis result ... 10
7 Precision... 10
8 Other ... 10
The second Method Cold Atomic Absorption Spectrometric Method ... 11
9 Principle... 11
10 Reagents and materials... 11
11 Apparatus ... 12
12 Analysis procedures ... 13
13 Representation of analysis result ... 14
14 Precision ... 14
15 Other ... 15
Chapter II Determination of methylmercury in foods ... 15
Liquid chromatography - atomic fluorescence spectrometry method ... 15
16 Principle... 15
17 Reagents and materials... 15
18 Apparatus ... 17
19 Analysis procedures ... 17
13 Representation of analysis result ... 19
21 Precision ... 20
22 Other ... 20
Annex A ... 21
Annex B ... 22
Foreword
This Standard replaces GB/T 5009.17-2003 Determination of Total Mercury and
Organic-mercury in Foods.
Compared with GB/T 5009.17-2003, the main changes are as follows.
- modified the standard name to “National Food Safety Standard-
Determination of total mercury and organic-mercury in foods”;
- deleted double sulphur hydrazone colorimetry method for determination
of total mercury, gas chromatography for determination of organic mercury
and atomic absorption spectrometry;
- added liquid chromatography - atomic fluorescence spectrometry (LC-
AFS) for determination of methylmercury.
National Food Safety Standard - Determination of total
mercury and organic-mercury in foods
1 Scope
The first chapter of this Standard specified the determination method for total
mercury in foods.
The first chapter of this Standard is applicable to the determination of total
mercury in foods.
The second chapter of this Standard specifies the liquid chromatography -
atomic fluorescence spectrometry for determination of methylmercury in foods.
The second chapter of this Standard is applicable to the determination of
methylmercury in foods.
Chapter I Determination of total mercury in foods
The first method Atomic fluorescence spectrometry
2 Principle
After the sample is heated and digested by acid, in acidic medium, mercury in
sample is reduced to atomic mercury by potassium borohydride or sodium
borohydride. It is brought by carrier gas (argon) into the atomizer. Under
irradiation of mercury hollow cathode lamp, ground state mercury atom is
stimulated to high energy state. When it is back from high energy state to
ground state, it shall emit the characteristic wavelength fluorescence. Its
fluorescence intensity is proportional to the mercury content, in quantitative
comparison with the standard series solution.
3 Reagents and materials
NOTE. Unless otherwise indicated, reagents used in this method are guaranteed
reagents; water is the grade one water specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Hydrogen peroxide (H2O2).
3.1.3 Sulfuric acid (H2SO4).
3.1.4 Potassium hydroxide (KOH).
3.1.5 Potassium borohydride (KBH4). analytically pure.
3.2 Reagent preparation
3.2.1 Nitric acid solution (1+9). measure 50 mL of nitric acid; slowly add it into
450 mL of water.
3.2.2 Nitric acid solution (95+5). measure 5 mL of nitric acid; slowly add it into
95 mL of water.
3.2.3 Potassium hydroxide solution (5g/L). weigh 5.0 g of potassium
hydroxide; dissolve it in pure water; set volume to 1000 mL; well mix it.
3.2.4 Solution of potassium borohydride (5g/L). weigh 5.0 g of potassium
borohydride; use 5g/L potassium hydroxide solution to dissolve and set volume
to 1000 mL; well mix it; prepare it when required.
3.2.5 Potassium dichromate nitric acid solution (0.5 g/L). weigh 0.05 g of
potassium dichromate to dissolve in 100 mL of nitric acid solution (5+95).
3.2.6 Nitric acid-perchloric acid mixed solution (5+1). measure 500 mL of
nitrate and 100 mL of perchloric acid; well mix.
3.3 Standard product
Mercuric chloride (HgCl2). purity ≥ 99%.
3.4 Preparation of standard solution
3.4.1 Mercury standard stock solution (1.00 mg/mL). accurately weigh 0.1354
g of dried mercuric chloride; use potassium dichromate nitric acid solution (0.5
g/L) to dissolve and transfer to 100 mL measuring flask; dilute it to scale; well
mix; the concentration of this solution is 1.00 mg/mL; store it in 4°C refrigerator
in dark conditions; it can be stored for 2 years; or purchase the standard solution
substance awarded by national certification standard certificate.
3.4.2 Mercury standard intermediate solution (10 μg/mL). pipette 1.00 mL of
mercury standard solution (1.00 mg/mL) in 100 mL measuring flask; use
potassium dichromate nitric acid solution (0.5 g/L) to dilute to scale; well mix;
sample OR pipette 1 mL ~ 5 mL of liquid sample (accurate to 0.001 g) into
digestion inner tank. Add 5 mL of nitrate to soak overnight. Cover the inner lid.
Tighten the stainless steel jacket. Place into thermostatic oven for 4h ~ 5h at
140°C ~ 160°C. Naturally cool it to room temperature in the oven. Then slowly
loosen the stainless steel jacket. Take it from the digestion inner tank. Use few
amount of water to clean the inner lid. Place on temperature control heating
plate or ultrasonic water bath. Drive away brown gas at 80°C or by 2 min ~ 5
min of ultrasonic degassing. Take the digestion inner tank out. Transfer the
digestive fluid to 25 mL flask. Use few amount of water to clean the inner tank
for 3 times. Combine the detergent in the flask and set volume to scale. Well
mix for use. Conduct the blank test at the same time.
5.2.2 Microwave digestion method
Weigh 0.2 g ~ 0.5 g (accurate to 0.001 g) of solid sample, 0.2 g ~ 0.8 g of fresh
sample OR pipette 1 mL ~ 3 mL of liquid sample into digestion inner tank. Add
5 mL ~ 8 mL of nitrate. Cover and place for overnight. Tighten the lid. Digest
according to the standard operation procedures of microwave digestion system
(see Table A.1 of Annex A for digestion reference conditions). Take it out after
cooling. Slowly open the tank to exhaust. Use few amount of water to clean the
inner lid. Place on temperature control heating plate or ultrasonic water bath.
Drive away brown gas at 80°C or by 2 min ~ 5 min of ultrasonic degassing. Take
the digestion inner tank out. Transfer the digestive fluid to 25 mL plastic flask.
Use few amount of water to clean the inner tank for 3 times. Combine the
detergent in the flask and set volume to scale. Well mix for use. Conduct the
blank test at the same time.
5.2.3 Reflux digestion method
5.2.3.1 Grain
Weigh 1.0 g ~ 4.0 g (accurate to 0.001 g) of sample. Place it in digestion
Erlenmeyer flask. Add few glass beads. Add 45 mL of nitric acid, 10 mL of
sulfuric acid. Rotate the Erlenmeyer flask to prevent partial carbonization. After
mounting condenser tube, low heat it when it starts bubbling. After bubbling
stops, heat it for 2h. If during heating, the solution turns brown, it shall add 5
mL of nitrate. Add 5 mL of nitrate, and continue refluxing for 2h till the sample
is dissolved by digestion. Generally, it appears light yellow or colorless. After ...
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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