Foreword
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This standard replaces GB 5009.15-2014 National food safety standard - Determination of cadmium in foods.
The following main modifications have been made with respect to GB 5009.15-2014:
——"Method II Inductively coupled plasma/mass spectrometry" has been added;
——"Annex A Temperature programming for microwave digestion and reference conditions for graphite furnace atomic absorption spectrometer" has been added;
——the subclause "Specimen preparation" has been modified;
——the wet digestion, digestion in pressure tank and microwave digestion have been modified, and the dry digestion has been deleted;
——the matrix modifier for graphite furnace atomic absorption spectrometry has been modified.
National food safety standard -
Determination of cadmium in foods
1 Scope
This standard specifies the determination of cadmium in foods by graphite furnace atomic absorption spectrometry and inductively coupled plasma/mass spectrometry.
This standard is applicable to the determination of cadmium in foods.
Method I Graphite furnace atomic absorption spectrometry
2 Principle
Atomize the digested specimen in a graphite furnace, and determine the absorbance at 228.8nm. Within a certain concentration range, the absorbance of cadmium is proportional to the cadmium content, which is quantified by comparing with the standard solution series.
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 Perchloric acid (HClO4).
3.1.3 Ammonium dihydrogen phosphate (NH4H2PO4).
3.1.4 Palladium nitrate [Pd(NO3)2].
3.2 Preparation of reagents
3.2.1 Nitric acid solution (5+95): measure 50mL nitric acid, and pour it slowly into 950mL water and mix well.
3.2.2 Nitric acid solution (1+9): measure 50mL nitric acid, and pour it slowly into 450mL water and mix well.
3.2.3 Ammonium dihydrogen phosphate-palladium nitrate mixed solution: weigh 0.02g palladium nitrate, dissolve it with a small amount of nitric acid solution (1+9), and then add 2g ammonium dihydrogen phosphate, after dissolution, dilute it with nitric acid solution (5+95) to 100mL, and mix well.
3.3 Reference material
Cadmium chloride (CdCl2•2.5H2O, CAS No.: 7790-78-5): with purity >99.99%, or its reference material certified by the state and issued with the reference material certificate.
Foreword i
1 Scope
Method I Graphite furnace atomic absorption spectrometry
2 Principle
3 Reagents and materials
4 Instruments and equipment
5 Analysis steps
6 Expression of analysis results
7 Precision
8 Others
Method II Inductively coupled plasma/mass spectrometry
Annex A Temperature programming for microwave digestion and reference conditions for graphite furnace atomic absorption spectrometer
