GB 5009.251-2016 PDF in English
GB 5009.251-2016 (GB5009.251-2016) PDF English
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Determination of 1, 2-propanediol in foods
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Standards related to (historical): GB 5009.251-2016
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GB 5009.251-2016: PDF in English GB 5009.251-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard - Determination of 1,2-
propylene glycol in food
ISSUED ON. AUGUST 30, 2016
IMPLEMENTED ON. MARCH 01, 2017
Issued by. National Health and Family Planning Commission of PRC
Table of Contents
Foreword ... 4
1 Scope ... 5
Method One -- Gas chromatography ... 5
2 Principle ... 5
3 Reagents and materials ... 5
4 Apparatus ... 6
5 Analysis steps ... 6
6 Expression of analysis results ... 9
7 Precision ... 9
8 Other ... 9
Method Two -- Gas chromatography-mass spectrometry ... 9
9 Principle ... 10
10 Reagents and materials ... 10
11 Apparatus ... 11
12 Analysis steps ... 11
13 Expression of analysis results ... 13
14 Precision ... 13
15 Other ... 13
Annex A Gas chromatogram of 1,2-propylene glycol standard sample solution
... 14
Annex B Selective ion chromatogram and ion mass spectrum of 1,2-propylene
glycol ... 15
National Food Safety Standard - Determination of 1,2-
propylene glycol in food
1 Scope
This Standard specifies the methods that use gas chromatography and gas
chromatography-mass spectrometry to determine 1,2-propylene glycol in food.
Method One of this Standard is applicable to the determination of 1,2-propylene
glycol in pastries, puffed food, cream, cheese, soy products, milk tablets, wet
noodle products, frozen drinks, liquid milk, vegetable protein drinks, milk
powder, butter, cream. Method Two is applicable to the determination of 1,2-
propylene glycol in pastries, puffed food, cheese, soy products, milk tablets, wet
noodle products.
Method One -- Gas chromatography
2 Principle
1,2-propylene glycol in the specimen is extracted by absolute ethanol. After the
extract is filtered, use gas chromatography to determine. Characterize by
retention time. Quantify by external standard method.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are analytically pure,
the water is grade two water specified in GB/T 6682.
3.1 Reagents
3.1.1 Anhydrous ethanol (C2H5OH).
3.1.2 Sea sand.
3.1.3 Acetonitrile (CH3CN).
3.1.4 Hexane [CH3(CH2)4CH3].
3.2 Preparation of reagent
The specimen is crushed by the mincer. Accurately weigh 5 g of well-mixed
specimen (to the nearest of 0.01g) to a 100mL stoppered conical flask. Add into
50.0 mL of absolute ethanol. Vortex and mix for 2min, then perform oscillation
extraction for 40min. After standing for 1h, use 0.45μm organic phase filter
membrane to filter. The filtrate obtained is put into gas chromatograph for
analysis.
5.1.2 Wet noddle products
The specimen is crushed by the mincer. Accurately weigh 2 g of well-mixed
specimen (to the nearest of 0.01g) into the mortar. Add an appropriate amount
of sea sand (the mass ratio of sea sand to sample is about 3.1 to 4.1) to grind
into dry powder. Transfer all to the 100mL stoppered conical flask. Add into 50.0
mL of absolute ethanol. Vortex and mix for 2min, then perform oscillation
extraction for 40min. After standing for 1h, use 0.45μm organic phase filter
membrane to filter. The filtrate obtained is put into gas chromatograph for
analysis.
5.1.3 Frozen drinks
A solid specimen is placed in a dry beaker to unfreeze. After melting, use a
glass rod to smash and stir evenly. The liquid specimen is put at room
temperature and shaken evenly. Accurately weigh 10 g of well-mixed specimen
(to the nearest of 0.01g) into a 50mL stoppered colorimetric tube. Use absolute
ethanol to set volume. Vortex and mix for 2min. After standing for 1h (centrifuge
at 8000 r/min for 5min if necessary), use 0.45μm organic phase filter membrane
to filter. The filtrate obtained is put into gas chromatograph for analysis.
5.1.4 Liquid milk, vegetable protein drinks
Accurately weigh 10 g of well-mixed specimen (to the nearest of 0.01g) into a
50mL stoppered colorimetric tube. Use absolute ethanol to set volume. Vortex
and mix for 2min. After standing for 1h (centrifuge at 8000 r/min for 5min if
necessary), use 0.45μm organic phase filter membrane to filter. The filtrate
obtained is put into gas chromatograph for analysis.
5.1.5 Milk powder
Accurately weigh 2 g of well-mixed specimen (to the nearest of 0.01g) into a
50mL stoppered colorimetric tube. Use 8 mL of 40°C water to dissolve and well
mix. Use absolute ethanol to set volume. Vortex and mix for 2min. After standing
for 1h (centrifuge at 8000 r/min for 5min if necessary), use 0.45μm organic
phase filter membrane to filter. The filtrate obtained is put into gas
chromatograph for analysis.
5.1.6 Butter, cream
Inject the specimen solution into the gas chromatograph. Obtain the peak area
of corresponding 1,2-propylene glycol. According to the standard curve, obtain
the mass concentration of 1,2-propylene glycol in the testing liquid.
See Figure A.1 for standard gas chromatograph of 1,2-propylene glycol.
6 Expression of analysis results
The content of 1,2-propylene glycol in specimen is calculated according to
formula (1).
where,
X - the content of 1,2-propylene glycol in specimen, in grams per kilogram (g/kg);
c - the concentration of 1,2-propylene glycol in specimen solution found in the
standard working curve, in microgram per milliliter (µg/mL);
V - the set volume of specimen, in milliliters (mL);
m - the specimen mass, in grams (g);
1000 - the conversion coefficient.
The calculated results are expressed as the arithmetic mean of two
independent determinations obtained under repetitive conditions. The result
remains three digits after the decimal point.
7 Precision
The absolute difference between two independent determinations obtained
under repeatability conditions shall not exceed 10% of the arithmetic mean.
8 Other
When the sampling amount is 5 g, the detection limit of this Standard is 0.01
g/kg; the limit of quantification is 0.03 g/kg.
Method Two -- Gas chromatography-mass
11 Apparatus
11.1 Gas chromatography-mass spectrometry (GC-MS). EI source.
11.2 Analytical balances. resolutions of 0.01g and 0.0001g.
11.3 Mincer.
11.4 Vortex mixer.
11.5 Cyclotron oscillator.
12 Analysis steps
12.1 Preparation of specimen
12.1.1 Pastries, puffed food, cheese, soy products, milk tablets
The specimen is crushed by the mincer. Accurately weigh 5 g of well-mixed
specimen (to the nearest of 0.01g) to a 100mL stoppered conical flask. Add into
50 mL of absolute ethanol. Vortex and mix for 2min, then perform oscillation
extraction for 40min. After standing for 1h, use anhydrous sodium sulfate (about
2 g) to filter. The filtrate obtained is put into gas chromatography-mass
spectrometry for analysis.
12.1.2 Wet noodle products
The specimen is crushed by the mincer. Accurately weigh 2 g of well-mixed
specimen (to the nearest of 0.01g) into the mortar. Add an appropriate amount
of sea sand (the mass ratio of sea sand to sample is about 3.1 to 4.1) to grind
into dry powder. Transfer all to the 100mL stoppered conical flask. Add into 50
mL of absolute ethanol. Vortex and mix for 2min, then perform oscillation
extraction for 40min. After standing for 1h, use anhydrous sodium sulfate (about
2 g) to filter. The filtrate obtained is put into gas chromatography-mass
spectrometry for analysis.
12.2 Instrument reference conditions
12.2.1 Chromatographic column. bonded/crosslinked polyethylene glycol
stationary phase quartz capillary column, 60m × 0.25mm, 0.25μm, or equivalent
column.
12.2.2 Carrier gas. high purity helium; constant current mode, column flow rate
of 1.0 mL/min.
12.2.3 Use program temperature rise. Column initial temperature is 80°C.
13 Expression of analysis results
The content of 1,2-propylene glycol in specimen is calculated according to
formula (2).
where,
X - the content of 1,2-propylene glycol in specimen, in grams per kilogram (g/kg);
c - the concentration of 1,2-propylene glycol in specimen solution found in the
standard working curve, in microgram per milliliter (µg/mL);
V - the set volume of specimen, in milliliters (mL);
m - the specimen mass, in grams (g);
1000 - the conversion coefficient.
The calculated results are expressed as the arithmetic mean of two
independent determinations obtained under repetitive conditions. The result
remains three digits after the decimal point.
14 Precision
The absolute difference between two independent determinations obtained
under repeatability conditions shall not exceed 10% of the arithmetic mean.
15 Other
When the sampling amount is 5 g, the detection limit of this Standard is 0.002
g/kg; the limit of quantification is 0.006 g/kg.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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