GB 31604.24-2016 English PDF (GB31604.24-2016)

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GB 31604.24-2016: Method for analysis of hygienic standard of ceramics for food containers
GB 31604.24-2016
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard
Food Contact Materials and Articles –
Determination of cadmium migration quantity
ISSUED ON. OCTOBER 19, 2016
IMPLEMENTED ON. APRIL 19, 2017
Issued by. National Health and Family Planning Commission of the PRC
Table of contents
Foreword ... 3 
1 Scope ... 4 
2 Principles ... 4 
3 Reagents and materials ... 4 
4 Instruments and equipment ... 6 
5 Analytical procedures ... 6 
6 Analysis results expression ... 7 
7 Precision... 7 
8 Other ... 7 
9 Principles ... 8 
10 Reagents and materials... 8 
11 Instruments and equipment ... 9 
12 Analytical procedures ... 9 
13 Analysis results expression ... 10 
14 Precision ... 10 
15 Other ... 10 
Appendix A Reference temperature raising program for graphite furnace
atomic absorption spectrometer ... 11 
Appendix B Reference operation conditions of flame atomic absorption
spectrometer ... 12 
Foreword
This standard instead of GB/T 5009.62-2003 “Method for analysis of hygienic
standard of ceramics for food containers”, GB/T 5009.63-2003 “Method for
analysis of hygienic standard of enamel for food containers”, GB/T
5009.72-2003 “Method for analysis of hygienic standard of aluminum-wares for
food use”, GB/T 5009.81-2003 “Method for analysis of hygienic standard of
stainless steel food containers and table wares”, GB/T 3534-2002 “Standard
testing methods for lead and cadmium release from domestic ceramic”, GB
8058-2003 “Standard permissible limits and testing method for release of lead
or cadmium from ceramic cookware”, GB/T 21170-2007 “Glass hollowware -
Test method for lead and cadmium release”, SN/T 2597-2010 “Determination
of lead, cadmium, chromium, arsenic, antimony, germanium migration quantity
in polymer for food contact materials - Inductively coupled plasma atomic
emission spectrometry method”, SN/T 2829-2011 “Food contact materials for
export - Metal materials - Determination of migrant heavy metals in food
simulant - Inductively coupled plasma atomic emission spectrometric method”,
SN/T 2886-2011 2011 “Food contact materials for export - Determination of
lead and cadmium in glass container simulant - Flame atomic absorption
spectrometry method”.
As compared with GB/T 5009.62-2003, the main changes of this standard are
as follows.
- CHANGE the standard name into “National Food Safety Standard - Food
Contact Materials and Articles - Determination of cadmium migration
quantity”;
- ADD the graphite furnace atomic absorption spectrometry;
- ADD the inductively coupled plasma mass spectrometry;
- ADD the inductively coupled plasma emission spectrometry;
- DELETE the dithizone colorimetric method.
National Food Safety Standard
Food Contact Materials and Articles –
Determination of cadmium migration quantity
1 Scope
This standard specifies the determination of cadmium migration quantity after
immersion of food contact materials and articles in food simulants by graphite
furnace atomic absorption spectrometry, inductively coupled plasma mass
spectrometry, inductively coupled plasma emission spectroscopy, and flame
atomic absorption spectrometry.
This standard applies to the determination of cadmium migration quantity in
food contact materials and articles.
Method I. Graphite furnace atomic absorption spectrometry
2 Principles
USE the food simulant to soak the portion of the food contact materials and
articles which is expected to contact with the food; MAKE the soaking solution
be subjected to graphite furnace atomization; AND the absorbance value
determined at 228.8 nm is proportional to the cadmium content within a certain
concentration range; COMPARE it with the standard series for quantitation.
3 Reagents and materials
Unless otherwise noted, the reagents used in this method are excellent grade
pure AND the water is level II water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Ammonium dihydrogen phosphate (NH4H2PO4).
specific concentration of cadmium in the standard solution. If the selected food
simulant is neutral or alkaline, it is required to add appropriate amount of nitric
acid to make the nitric acid concentration in this solution reach to about 5%
(volume fraction).
4 Instruments and equipment
Note. All glassware need to be soaked in nitric acid solution (1+5) overnight,
repeatedly rinsed with tap water, and finally washed clean with water.
4.1 Graphite furnace atomic absorption spectrometer. It is equipped with
graphite furnace atomizer and cadmium hollow cathode lamp.
4.2 Analytical balance. The sensitivity is of 0.1 mg.
5 Analytical procedures
5.1 Sample pre-treatment
According to the expected use and conditions of use of the sample to be tested,
CONDUCT the migration test in accordance with the migration test method
and test conditions as specified in GB 5009.156 and GB 31604.1. After the
soaking solution is fully mixed, TAKE a portion of soaking solution for analysis
purposes. If the soaking solution is neutral or alkaline, ADD appropriate
amount of nitric acid to make the concentration of nitric acid in the test solution
at about 5% (volume fraction). At the same time, CONDUCT sample blank
test.
5.2 Determination
5.2.1 Instrument reference conditions
The instrument reference conditions are as shown in Table A.
5.2.2 Standard curve making
In the order of concentration from low to high, respectively PIPETTE 10 μL of
cadmium standard series solution and 5 μL of ammonium dihydrogen
phosphate solution (20 g/L) (the optimum injection volume can be determined
according to the instrument used); simultaneously INJECT them into the
graphite furnace to determine its absorbance value; USE the concentration of
the standard series solution as the abscissa AND the corresponding
absorbance as the ordinate, to draw the standard curve.
nitric acid solution (1+9) to dissolve it; TRANSFER it into a 1000 mL volumetric
flask; ADD water to the mark; MIX it uniformly.
10.4.2 Cadmium standard intermediate (10.0 mg/L). PIPETTE 10.0 mL of
cadmium standard stock solution into a 100 mL volumetric flask; ADD nitric
acid solution (5+95) to the mark; MIX it uniformly.
10.4.3 Cadmium standard series solution. Respectively PIPETTE 0 mL, 1.00
mL, 2.00 mL, 4.00 mL, 6.00 mL, and 8.00 mL of cadmium standard
intermediate (10.0 mg/L) into 100 mL volumetric flasks; ADD the
corresponding food simulant to the mark; MIX it uniformly, in order to make the
concentration of the standard solution series in 0 mg/L, 0.100 mg/L, 0.200
mg/L, 0.400 mg/L, 0.600 mg/L and 0.800 mg/L, respectively.
Note. It may be based on the sensitivity of the instrument, the linear range and
the actual concentration of cadmium in the soaking solution to determine the
specific concentration of cadmium in the standard solution. If the selected food
simulant is neutral or alkaline, it is required to add appropriate amount of nitric
acid to make the nitric acid concentration in this solution reach to about 5%
(volume fraction).
11 Instruments and equipment
Note. All glassware need to be soaked in nitric acid solution (1+5) overnight,
repeatedly rinsed with tap water, and finally washed clean with water.
11.1 Flame atomic absorption spectrometer. It is equipped with flame atomizer
and cadmium hollow cathode lamp.
11.2 Analytical balance. The sensitivity is of 0.1 mg.
12 ...