Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard replaces the determination of lead and its migration in 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 5009.78-2003 Method for Analysis of Hygienic Standard of Papers for Food Packaging, 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, Determination of Lead, Cadmium, Chromium, Arsenic, Antimony, SN/T 2597-2010 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 Food Contact Materials for Export - Glasswork - Determination of Lead and Cadmium in Food Simulants - Flame Atomic absorption Spectrometry (FAAS) 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 changes have been made with respect to GB/T 5009.62-2003 (the previous edition):
——The standard name is revised as "National Food Safety Standard - Food Contact Materials and Articles - Determination of Lead and Its Migration";
——Determination of lead is added;
——Graphite furnace atomic absorption spectrometry is added;
——Inductively coupled plasma mass spectrometry is added;
——Inductively coupled plasma emission spectrometry is added;
——Dithizone colorimetry is deleted.
National Food Safety Standard
Food Contact Materials and Articles
Determination of Lead and Its Migration
1 Scope
This standard specifies graphite furnace atomic absorption spectrometry, inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectrometry and flame atomic absorption spectrometry for the determination of lead migration in food contact materials and articles after soaking in food simulants after being soaked in food simulants and determination of lead in paper products and corks.
This standard is applicable to the determination of lead migration in food contact materials and articles and lead in paper products and corks.
Part I Determination of Lead
Method I Graphite Furnace Atomic Absorption Spectrometry
2 Principle
Digest the paper product and cork with dry method after grinding, atomize the digestion solution through graphite furnace. Within certain concentration range, absorption value is in direct proportion to lead content at 283.3nm, and is compared with standard series for quantification.
3 Reagents and Materials
Unless otherwise specified, guaranteed reagents and Class-II water (defined in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents
3.1.1 Nitric acid (HNO3).
3.1.2 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.3 Palladium nitrate [Pd(NO3)2].
3.2 Preparation of reagents
3.2.1 Nitric acid solution (5+95): measure 50mL nitric acid, add into 950mL water and mix uniformly.
3.2.2 Nitric acid solution (1+9): measure 50mL nitric acid, add into 450mL water and mix uniformly.
3.2.3 Nitric acid solution (1+1): measure 50mL nitric acid, add into 50mL water and mix uniformly.
3.2.4 Ammonium dihydrogen phosphate - palladium nitrate solution: weigh 0.020g palladium nitrate, dissolve with a small amount of nitric acid solution (1+9), add 2.0g ammonium dihydrogen phosphate, scale the volume with nitric acid solution (5+95) to 100mL after dissolution, and mix uniformly.
3.3 Standard product
Lead nitrate [Pb(NO3)2, CAS No.: 10099-74-8]: purity >99.99%, or lead standard solution in certain concentration approved and awarded with reference material certificate by the State.
3.4 Preparation of standard solutions
3.4.1 Lead standard stock solution (1000mg/L): accurately weigh 1.5985g (accurate to 0.0001g) lead nitrate, dissolve in a small amount of nitric acid solution (1+9), transfer into a 1000mL volumetric flask, add water to the scale and mix uniformly.
3.4.2 Lead standard intermediate solution (1.00mg/L): pipet 1.00mL lead standard stock solution into a 1000mL volumetric flask, add nitric acid solution (5+95) to the scale and mix uniformly.
3.4.3 Lead standard series solution: pipet 0mL, 0.500mL, 1.00mL, 2.00mL, 3.00mL and 4.00mL lead standard intermediate solutions (1.00mg/L) respectively into 100mL volumetric flasks, add nitric acid solution (5+95) to the scale and mix uniformly. The concentrations of such lead standard series solutions are 0μg/L, 5.00μg/L, 10.0μg/L, 20.0μg/L, 30.0μg/L and 40.0μg/L respectively.
Note: the specific concentration of lead in standard solution series may be determined according to the sensitivity and linear range of instruments and actual content of lead in sample.
4 Instruments and Apparatus
Note: all glassware shall be soaked in nitric acid solution (1+5) overnight, flushed with tap water repeatedly, and finally washed clean with water.
4.1 Atomic absorption spectrometer: equipped with graphite furnace atomizer and lead hollow cathode lamp.
4.2 Adjustable electric hot plate.
4.3 Muffle furnace.
4.4 Analytical balance: with sensibility of 0.1mg and 1mg.
5 Analysis Steps
5.1 Digestion of specimen
Take appropriate amount of sample, grind and mix uniformly. Weigh 1~5g (accurate to 0.001g) specimen into the crucible, carbonize till smokeless on adjustable electric hot plate with soft fire, transfer into the muffle furnace and ash for 6~8h at 500℃, then cool down. For individual specimen with inexhaustive ashing, add 1mL nitric acid and heat on adjustable electric hot plate with soft fire, repeat for many times till totally digested, cool down, and dissolve the ash content with nitric acid solution (1+1), transfer into a 25mL volumetric flask, wash the crucible with a small amount of water for many times, merge the washing solution into a volumetric flask, scale the volume to the scale and mix uniformly for standby. Meanwhile, carry out reagent blank.
5.2 Determination
5.2.1 Test conditions of instruments
See Table A.1 for reference conditions.
5.2.2 Plotting of standard curve
Simultaneously inject 10μL lead standard series solution and 5μL palladium nitrate ammonium dihydrogen phosphate solution (optimum injection volume may be determined according to the adopted instrument) into graphite furnace from low concentration to high concentration, determine the absorbance value after atomization and plot the standard curve with the concentration as x-axis and the absorbance value as y-axis.
5.2.3 Determination of specimen
Simultaneously inject 10μL blank solution or specimen solution and 5μL palladium nitrate ammonium dihydrogen phosphate solution (optimum injection volume may be determined according to the adopted instrument) into graphite furnace, determine their absorbance values after atomization and compare with standard series for quantification.
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 Temperature Rise Procedures of Graphite Furnace Atomic absorption Spectrometer
Annex B Operating Reference Conditions of Flame Atomic Absorption Spectrometer
