GB 31604.33-2016 PDF in English
GB 31604.33-2016 (GB31604.33-2016) PDF English
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National Food Safety Standard -- Food Contact Materials and Articles -- Determination of Migration of Nickel
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Standards related to (historical): GB 31604.33-2016
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GB 31604.33-2016: PDF in English GB 31604.33-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard -
Food contact materials and products
Determination of nickel migration
ISSUED ON. OCTOBER 19, 2016
IMPLEMENTED ON. APRIL 19, 2017
Issued by. National Health and Family Planning Commission of the
People’s Republic of China
Table of Contents
Foreword . 3
1 Scope .. 4
2 Principle . 4
3 Reagents and materials . 4
4 Instruments and equipment .. 6
5 Analysis procedure .. 6
6 Expression of analysis results .. 7
7 Precision . 7
8 Others . 7
9 Principle . 7
10 Reagents and materials . 8
11 Instruments and equipment .. 10
12 Analysis procedure . 10
13 Expression of analysis results . 11
14 Precision . 11
15 Others . 11
Annex A Reference temperature rise program of graphite furnace atomic
absorption spectrometer . 12
Foreword
This Standard replaces the determination method for nickel migration in GB/T
5009.81-2003 “Method for analysis of hygienic standard of stainless steel food
containers and table wares” and 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”.
Compared with the determination method for nickel in GB/T 5009.81-2003, the
main changes are as follows.
- MODIFY the standard name TO “National food safety standard - Food
contact materials and products - Determination of nickel migration”;
- ADD Inductively coupled plasma mass spectrometry and inductively
coupled plasma atomic emission spectrometry.
National food safety standard -
Food contact materials and products
Determination of nickel migration
1 Scope
This Standard specifies the graphite furnace atomic absorption spectrometry,
inductively coupled plasma mass spectrometry, inductively coupled plasma
atomic emission spectrometry and spectrophotometric method using
dimethylglyoxime for the determination of nickel migration in food contact
materials and products after being soaked in food simulants.
This Standard applies to the determination of nickel migration in food contact
materials and products.
Method I -- Graphite furnace atomic absorption spectrometry
2 Principle
Use food simulants to soak parts of food contact materials and products that
are expected to come in contact with foods. The soaking solution is atomized
in a graphite furnace. The absorbance measured at 232.0 nm is proportional to
the nickel content within a certain concentration range, which is compared with
the standard series to quantify.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are all guarantee
reagents, and the water is grade-2 water specified in GB/T 6682.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.3 Reagents for preparing food simulants. According to specifications of GB
31604.1.
4 Instruments and equipment
NOTE. All glassware must be soaked in nitric acid solution (1 + 5) overnight and rinsed
with water for later use.
4.1 Atomic absorption spectrometer. equipped with graphite furnace atomizer,
nickel hollow cathode lamp.
4.2 Analytical balance. with a division of 0.1 mg.
5 Analysis procedure
5.1 Pretreatment of samples
According to the expected use and the use conditions of the sample to be tested,
carry out the migration test in accordance with the migration test methods and
test conditions specified in GB 5009.156 and GB 31604.1. After the soaking
solution is thoroughly mixed, take part of the soaking solution for analysis. If the
soaking solution is neutral or alkaline, add an appropriate amount of nitric acid
so that the concentration of nitric acid in the test solution is about 5 % (volume
fraction). At the same time carry out the sample blank test.
5.2 Determination
5.2.1 Instrument test conditions
Instrument reference conditions are shown in Table A.1.
5.2.2 Plotting of standard curves
PIPETTE 10 μL of nickel standard solution and 5 μL of ammonium dihydrogen
phosphate solution (20 g/L) (the optimal injection volume may be determined
in accordance with the instrument used) in the order of concentration from low
to high, INJECT them into the graphite furnace at the same time. After
atomization, MEASURE the absorbance value. Take the concentrations of the
standard series as the abscissa and take the corresponding absorbance values
as the ordinate to plot the standard curve.
5.2.3 Determination of samples
Under the same test conditions as those for the determination of standard
solution, PIPETTE 10 μL of sample solution and 5 μL of ammonium dihydrogen
phosphate solution (20 g/L) (the optimal injection volume may be determined
in accordance with the instrument used), INJECT them into the graphite furnace
at the same time. After atomization, MEASURE the absorbance value.
ammonia to decolorize, then reacts with basic dimethylglyoxime to form red
complexes, which are compared with the standard series to quantify.
10 Reagents and materials
Unless otherwise stated, the reagents used in this method are all analytical
reagents, the water is the grade-3 water specified in GB/T 6682.
10.1 Reagents
10.1.1 Diammonium hydrogen nitrite [(NH4)2HC6H5O7].
10.1.2 Dimethylglyoxime [(CH3)2C2(NOH)2].
10.1.3 Ethanol (C2H5OH).
10.1.4 Chloroform (CHCl3).
10.1.5 Bromine Water (Br2).
10.1.6 Sodium hydroxide (NaOH).
10.1.7 Hydrochloric acid (HCl).
10.1.8 Ammonia (NH3 · H2O).
10.1.9 Nitric acid (HNO3). excellent regent.
10.1.10 Reagents for preparing food simulants. according to the specifications
of GB 31604.1.
10.2 Preparation of reagents
10.2.1 Diammonium hydrogen nitrite solution (100 g/L). WEIGH 10 g of
diammonium hydrogen nitrite and DISSOLVE in water to 100 mL.
10.2.2 Ethanol solution (95 + 5). ADD 5 mL of water to 95 mL of ethanol, MIX
well.
10.2.3 Dimethylglyoxime ethanol solution (10 g/L). DISSOLVE 1 g of
dimethylglyoxime and DISSOLVE in 100 mL of ethanol solution (95 + 5), MIX
well. If there is any insoluble material, filter and the filtrate is for later use.
10.2.4 Sodium hydroxide solution (0.2 mol/L). DISSOLVE 1.0 g of sodium
hydroxide in 125 mL of water.
10.2.5 Basic dimethylglyoxime solution (10 g/L). WEIGH 1 g of
11 Instruments and equipment
NOTE. All glassware must be soaked in nitric acid solution (1 + 5) overnight and rinsed
with water for later use.
11.1 Spectrophotometer. with 1 cm cuvette.
11.2 Analytical balance. with a division of 0.1 mg.
12 Analysis procedure
12.1 Pretreatment of samples
The same as subclause 5.1.
12.2 Determination
12.2.1 Plotting of standard curves
Respectively PIPETTE 0 mL, 0.250 mL, 0.500 mL, 1.00 mL, 2.00 mL, 3.00 mL,
4.00 mL, 5.00 mL of nickel standard use solution (10.0 mg/L) to 100-mL
volumetric flasks, ADD food simulants to the mark, the corresponding
concentration series are 0 μg/L, 25.0 μg/L, 50.0 μg/L, 100 μg/L, 200 μg/L, 300
μg/L, 400 μg/L and 500 μg/L. ADD sodium hydroxide solution (20 %) to adjust
to neutral or weak alkaline, LET STAND for 2 h, FILTER, TRANSFER the filtrate
into a 250-mL separatory funnel, ADD 2 mL of diammonium hydrogen nitrite
solution (100 g/L), ADD a few drops of ammonia solution (2 mol/L) to adjust the
solution pH to 8 ~ 9. ADD 2 mL of dimethylglyoxime ethanol solution (10 g/L),
ADD 10 mL of chloroform, vigorously SHAKE for 1 min, LET STAND,
SEPARATE chloroform into a 60-mL separatory funnel. ADD 5 mL of chloroform
to the aqueous layer and REPEAT the above operations twice, COMBINE
chloroform solution, DISCARD the aqueous layer. USE 10 mL of ammonia
solution (0.3 mol/L) to wash the chloroform layer, vigorously SHAKE for 30 s,
LET STAND, SEPARATE the chloroform layer into another 60-mL separatory
funnel; ADD 10 mL of hydrochloric acid solution (0.5 mol/L) to the funnel,
vigorously SHAKE for 1 min, LET STAND, SEPARATE the chloroform layer into
another separatory funnel. ADD 5 mL of hydrochloric acid solution (0.5 mol/L)
and operate as above, COMBINE the hydrochloric acid solution, TRANSFER
to a 25-mL colorimetric tube with stopper, ADD 2 mL of bromine water, SHAKE.
LET STAND for 1 min, ADD ammonia solution (5 mol/L) until colorless, ADD 2
mL of ammonia solution (5 mol/L), COOL to room temperature in running water.
ADD 2 mL of basic dimethylglyoxime solution (10 g/L), ADD water to 25 mL and
MIX thoroughly, LET STAND for 20 min. DETERMINE the absorbance at 540
nm. TAKE the absorbance as the ordinate and the standard concentration as
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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