GB 31604.41-2016 PDF in English
GB 31604.41-2016 (GB31604.41-2016) PDF English
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Determination of antimony in polyester resin and products for food containers and packaging materials
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Standards related to (historical): GB 31604.41-2016
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GB 31604.41-2016: PDF in English GB 31604.41-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard - Food Contact Materials
and Articles - Determination of Stibium 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 . 4
1 Scope .. 5
2 Principle.. 5
3 Reagents and materials .. 5
4 Instruments and equipment . 7
5 Analysis steps . 7
6 Expression of analysis results .. 8
7 Precision. 8
8 Other . 8
9 Principle.. 8
10 Reagents and materials. 8
11 Instruments and equipment .. 10
12 Analysis steps .. 10
13 Expression of analysis results . 11
14 Precision .. 11
15 Other .. 11
16 Principle. 11
17 Reagents and materials.. 12
18 Instruments and equipment .. 13
19 Analysis steps .. 13
20 Expression of analysis results . 14
21 Precision .. 15
22 Other .. 15
Annex A Reference heating program of graphite furnace atomic absorption
spectrometer . 16
Annex B Reference working conditions of atomic fluorescence spectrometer
. 17
National Food Safety Standard - Food Contact Materials
and Articles - Determination of Stibium Migration
1 Scope
This Standard specifies the graphite furnace atomic absorption spectrometry,
atomic fluorescence spectrometry, inductively coupled plasma mass
spectrometry, inductively coupled plasma emission spectrometry, and
malachite green spectrophotometry for the determination of stibium migration
after food contact materials and articles are soaked in food simulants.
This Standard is applicable to the determination of stibium migration in food
contact materials and articles.
Method One -- Graphite furnace atomic absorption
spectrometry
2 Principle
Use the food simulant to immerse the parts of food contact materials and
articles intended to come into contact with food. Soaking solution is atomized
by graphite furnace. The absorption value measured at 231.2 nm is proportional
to the cerium content over a range of concentrations. Compare and quantify
with the standard series.
3 Reagents and materials
Unless otherwise stated, the reagents used in this method are all superior-
grade pure, and the water is Grade two water specified in GB/T 6682.
3.1 Reagents
3.1.1 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.2 Hydrochloric acid (HCl).
3.1.3 Sulfuric acid (H2SO4).
3.1.4 Nitric acid (HNO3).
4 Instruments and equipment
NOTE. All glassware needs to be soaked overnight with nitric acid solution (1+5). Rinse clean with water.
4.1 Atomic absorption spectrometer. with graphite furnace atomizer, stibium
hollow cathode lamp.
4.2 Analytical balance. resolution of 0.1 mg.
5 Analysis steps
5.1 Sample pretreatment
According to the expected use of the testing sample and the conditions of use,
with the migration test methods and test conditions specified in GB 5009.156
and GB 31604.1, the migration test shall be carried out. After the soaking
solution is fully mixed, take some soaking test solution for analysis. If the
soaking test solution is neutral or alkaline, add appropriate amount of nitric acid
to make the concentration of nitric acid in the test solution about 5% (volume
fraction). Perform the sample blank test at the same time.
5.2 Determination
5.2.1 Instrument test conditions
See Table A.1 for instrument test conditions.
5.2.2 Making of standard curve
According to the order of concentration from low to high, pipette 10 μL of
standard solution series and 5 μL of ammonium dihydrogen phosphate solution
(20 g/L) (the best injection volume can be determined according to the
instrument used) into the graphite furnace at the same time. After atomization,
determine the absorbance value. Take the standard series concentration as the
abscissa, the corresponding absorbance value as the ordinate to draw a
standard curve.
NOTE. Based on the sensitivity of the instrument, the linear range, and the actual content of deuterium
in the sample solution, the concentration and range of stibium in the standard series solution can be
determined.
5.2.3 Sample determination
Under the same experimental conditions as the determination of standard
solution, pipette 10 μL of the sample solution and 5 μL of ammonium dihydrogen
phosphate solution (20 g/L) (the best injection volume can be determined
10.1.2 Potassium borohydride (KBH4).
10.1.3 Thiourea (CH4N2S).
10.1.4 Ascorbic acid (C6H8O6).
10.1.5 Hydrochloric acid (HCl). superior-grade pure.
10.1.6 Reagents for preparing food simulants. according to GB 31604.1.
10.2 Reagent preparation
10.2.1 Hydrochloric acid solution (1+9). measure 50 mL of hydrochloric acid,
add 450 mL of water, mix well.
10.2.2 Hydrochloric acid solution (5%). measure 10 mL of hydrochloric acid,
add water to 200 mL, and mix well. Prepare before use.
10.2.3 Potassium borohydride alkaline solution (20 g/L). weigh 2.5 g of
sodium hydroxide dissolved in water, completely dissolve, add 10 g of
potassium borohydride, add water to 500 mL, and mix well. Prepare before use.
10.2.4 Thiourea-ascorbic acid solution. respectively pipette 10 g of thiourea
and 10 g of ascorbic acid, dissolve in water and add water and set volume to
100 mL. Prepare before use.
10.2.5 Food simulant. prepare in accordance with the provisions of GB
5009.156.
10.3 Standard product
Metal stibium (Sb, CAS No. 7440-36-0). purity >99.99% or the standard solution
certified by the state and granted with a standard substance certificate.
10.4 Preparation of standard solution
10.4.1 Stibium standard stock solution (500 mg/L). see 3.4.1.
10.4.2 Stibium standard intermediate solution (10.0 mg/L). transfer 2.00 mL
of stibium standard stock solution (500 mg/L); place in a 100mL volumetric flask;
dilute to the scale with hydrochloric acid solution (1+9); mix well.
10.4.3 Stibium standard use solution (0.100 mg/L). accurately transfer 1.00
mL of standard intermediate solution (10.0 mg/L) into a 100 mL volumetric flask;
dilute to the scale with water; mix well.
100mL of water, mix well.
17.3 Standard product
Metal strontium (Sb, CAS number. 7440-36-0). purity > 99.99%, or a standard
solution that has been certified by the state and granted with a standard
substance certificate.
17.4 Preparation of standard solution
17.4.1 Stibium standard stock solution (500 mg/L). same as 3.4.1.
17.4.2 Stibium standard use solution (10.0 mg/L). take 2mL of stibium
standard stock solution, dilute to 100mL with sulfuric acid solution (1+5).
18 Instruments and equipment
NOTE. All glassware needs to be soaked overnight with nitric acid solution (1+5). Rinse clean with water
for use.
18.1 Spectrophotometer. with 1cm cuvette.
18.2 Analytical balance. resolution of 0.1mg.
19 Analysis steps
19.1 Sample pretreatment
Same with 5.1.
19.2 Determination
19.2.1 Making of standard curve
Take 0 mL, 0.300 mL, 0.400 mL, 0.600 mL, 0.800 mL, 1.00 mL (equivalent to 0
μg, 3.00 μg, 4.00 μg, 6.00 μg, 8.00 μg, 10.0 μg of stibium) of stibium standard
use solutions. Respectively place them in separatory funnels added with 4 mL
of water and 4 mL of hydrochloric acid solution (5+1). Add 2 drops of stannous
chloride solution (12%). Mix well. Place 5min. Add 1mL of sodium nitrite solution
(20%). Mix well. And blow the air with a rubber suction ball to chase the brown
nitrogen oxide gas in the separatory funnel. Then add 2.5mL of urea solution
(1000 g/L). Shake well and mix thoroughly. Put into the solution and no bubbles
escape. Add 1mL of malachite green solution (0.2%). Add 10mL of sodium
citrate solution (20%). Then add 5mL of isoamyl acetate. Fully shake for 30s.
Place for stratification. Discard the aqueous phase. The organic phase passes
through a small funnel pre-filled with a little anhydrous sodium sulfate. The
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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