National Food Safety Standard -Food Contact Materials and Articles – Determination of Arsenic, Cadmium, Chromium and Lead; Migration of Arsenic, Cadmium, Chromium, Nickel, Lead, Antimony and Zinc
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This standard replaces the determination for migration of arsenic, cadmium, chromium, nickel, lead, antimony and zinc as well as the determination of arsenic, chromium, chromium and lead content in paper product and cork in 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 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 and SN/T 2594-2010 Food contact materials - Determination of Lead, Cadmium, Chromium, and Arsenic in Cork Stoppers by Inductively Coupled Plasma Mass Spectrometry.
The following main changes have been made with respect to SN/T 2829-2011, SN/T 2597-2010 and SN/T 2594-2010 (the previous editions):
——Standard name is revised as "National Food Safety Standard - Food Contact Materials and Articles - Determination of Arsenic, Cadmium, Chromium and Lead; Migration of Arsenic, Cadmium, Chromium, Nickel, Lead, Antimony and Zinc".
National Food Safety Standard
Food Contact Materials and Articles - Determination of Arsenic, Cadmium, Chromium and Lead; Migration of Arsenic, Cadmium, Chromium, Nickel, Lead, Antimony and Zinc
1 Scope
This standard specifies the inductively coupled plasma mass spectrometry and inductively coupled plasma emission spectrometry for the determination of arsenic, cadmium, chromium, nickel, lead, antimony and zinc migration after the food contact materials and articles are soaked in food simulants and specifies the inductively coupled plasma mass spectrometry for the determination of arsenic, cadmium, chromium and lead elements in paper products and corks.
This standard is applicable to the determination of arsenic, cadmium, chromium, nickel, lead, antimony and zinc migration in various food contact materials and articles and the determination of arsenic, cadmium, chromium and lead in paper products and corks.
Part I Determination of Arsenic, Cadmium, Chromium and Lead
Inductively Coupled Plasma Mass Spectrometry
2 Principle
After chipping, digest the paper products and corks with nitric acid, dilute the obtained solution with water and scale the volume, determine with the inductively coupled plasma mass spectrometer and compare with standard series for quantification.
3 Reagents and Materials
Unless otherwise specified, guaranteed reagents and Class-I water (defined in GB/T 6682) are adopted for the purposes of this method.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Argon (Ar): with purity ≥99.99%, or liquid argon.
3.1.3 Helium (He), with purity ≥99.995%.
3.2 Preparation of reagents
Nitric acid solution (5+95): measure 50mL nitric acid, slowly add into 950mL water and mix uniformly.
3.3 Standard product
3.3.1 Element standard stock solution (1000mg/L or 100mg/L): simple-element or multiple-element standard stock solutions approved and awarded with reference material certificate by the State are adopted for arsenic, cadmium, chromium and lead.
3.3.2 Internal standard element stock solution (1000mg/L or 100mg/L): simple-element or multiple-element standard stock solutions approved and awarded with reference material certificate by the State are adopted for scandium, germanium, indium, rhodium, rhenium, bismuth, etc.
3.4 Preparation of standard solutions
3.4.1 Mixed standard series solution: accurately pipet appropriate amount of single-element standard stock solution or multiple-element mixed standard stock solution, and dilute with nitric acid solution (5+95) step by step to prepare into mixed standard series solution, refer to Table 1 for concentrations of elements. After preparation, transfer the mixed standard series solution into a clean polyethylene bottle for preservation.
Note: concentration and range of this element in the standard series solution may be determined according to the sensitivity and linear range of instruments and actual content of elements in sample solution.
Table 1 Mixed Standard Series Solution
S.N. Element Concentration of standard series/(μg/L)
Series 1 Series 2 Series 3 Series 4 Series 5 Series 6
1 As 0 0.200 1.00 5.00 10.0 20.0
2 Cd 0 0.020 0 0.100 0.500 1.00 2.00
3 Cr 0 0.500 1.00 5.00 10.0 20.0
4 Pb 0 0.500 2.00 10.0 20.0 50.0
3.4.2 Internal standard working solution (1mg/L): take appropriate amount of internal standard single-element stock solution or internal standard multiple-element stock solution, prepare into the appropriate concentration of multiple-element internal standard working solution with nitric acid solution (5+95).
Note: the internal standard solution may be added quantitatively by hand during preparation of the mixed standard series solution and the to-be-tested sample solution, or added online with instrument. If the sample injection volume to the internal standard injection volume is 20:1, the concentration of the internal standard is suggested as 1~2mg/L; if it is 1:1, the concentration of the internal standard is suggested as 50~100μg/L.
3.4.3 Instrument tuning working solution: according to the requirements of the instrument operation instructions, take appropriate amount of instrument tuning stock solution and prepare into the appropriate concentration of tuning solution with nitric acid solution (5+95).
4 Instruments and Apparatus
Note: all glassware and polytetrafluoroethylene digestion inner tanks shall be soaked in nitric acid solution (1+5) overnight, flushed thoroughly with ultra-pure water for standby.
4.1 Inductively coupled plasma mass spectrometer.
4.2 Analytical balance: with the sensitivity of 0.1mg.
4.3 Microwave digestion system: equipped with polytetrafluoroethylene digestion inner tank.
4.4 Pressure digester: equipped with polytetrafluoroethylene digestion inner tank.
4.5 Thermostatic drying oven (oven).
4.6 Temperature control electric hot plate.
4.7 Ultrasonic water bath.
4.8 Sample grinding equipment.
5 Analysis Steps
5.1 Preparation of specimen
Take appropriate amount of sample, cut or grind the sample with cutting/grinding machine into powder and mix uniformly.
5.2 Digestion of specimen
5.2.1 Airtight microwave digestion
Weigh 0.5g ground specimen (accurate to 0.1mg), put into the polytetrafluoroethylene digestion inner tank, add 5~8mL nitric acid, cover and place for 1h, put the digestion tank into the microwave digestion system after sealing, digest according to the standard operating procedures of the microwave digestion system and by reference to the digestion conditions as described in A.6. After the digestion, remove the digester from the digestion tank, slowly open the inner cover after complete cooling of the digestion tank, wash the inner cover with a small amount of water for two times and merge into the digestion tank. Put the digestion tank on the temperature control electric hot plate for heating for 30min at 140℃, or put into ultrasonic water bath for ultrasonic degassing for 5min, transfer all digestion solution into a 50mL volumetric flask, dilute with water to the scale and mix uniformly for test. Meanwhile, carry out the specimen blank.
5.2.2 Pressurized airtight digestion
Weigh 0.5g ground specimen (accurate to 0.1mg), put into the polytetrafluoroethylene digestion inner tank, add 5~8mL nitric acid, cover and place for 1h, seal the digestion inner tank into the stainless steel outer tank, digest in the thermostatic drying oven by reference to the digestion conditions as described in A.6. After the digestion, slowly open the inner cover after complete cooling of the digestion tank, wash the inner cover with a small amount of water for two times and merge into the digestion tank. Put the digestion tank on the temperature control electric hot plate for heating for 30min at 140℃, or put into ultrasonic water bath for ultrasonic degassing for 5min, transfer all digestion solution into a 50mL volumetric flask, dilute with water to the scale and mix uniformly for test. Meanwhile, carry out the specimen blank.
Foreword i
1 Scope
2 Principle
3 Reagents and Materials
4 Instruments and Apparatus
5 Analysis Steps
6 Expression of Analysis Results
7 Accuracy
8 Other
9 Principle
10 Reagents and Materials
11 Instruments and Apparatus
12 Analysis Steps
13 Expression of Analysis Results
14 Accuracy
15 Other
16 Principle
17 Reagents and Materials
18 Instruments and Apparatus
19 Analysis Steps
20 Expression of Analysis Results
21 Accuracy
22 Other
Annex A Reference Working Conditions of Instruments and Recommended Mass-to-charge Ratio or Analysis Wavelength of All Elements
