1 Scope
This standard specifies various methods for determination of cadmium in foods.
This standard is applicable to the determination of cadmium in various foods.
Detection limit in this method: 0.1μg/kg for graphite furnace atomization method; 5.0μg/kg for flame atomization method; 50μg/kg for colorimetric method; l.2μg/kg for atomic fluorescence method and 0~50ng/mL for linear range of standard curve.
Method 1 Graphite Furnace Atomic Absorption Spectrometry
2 Principle
The samples shall be incinerated or digested in acid, and then injected into the graphite furnace of atomic absorption spectrophotometer; the resonance line of 283.3nm shall be absorbed after electrothermal atomization, and its absorption value is proportional to the cadmium content within a certain concentration range, and is determined by comparing with the standard series.
3 Reagents
3.1 Nitric acid.
3.2 Sulfuric acid.
3.3 Hydogen peroxide (30%).
3.4 Barium perchlorate.
3.5 Nitric acid (1+1): take 50mL of nitric acid and add it into 50mL water slowly.
3.6 Nitric acid (0.5mol/L): take 3.2mL of nitric acid to add into 50mL water and dilute it until 100mL.
3.7 Hydrochloric acid 1+1): take 50mL of hydrochloric acid and add it into 50mL water slowly.
3.8 Ammonium phosphate solution (20g/L): weigh 2.0g of ammonium phosphate and dissolve it with water to dilute until 100mL.
3.9 Mixed acid: nitric acid+perchloric acid (4+1). Mix four shares of nitric acid and one share of perchloric acid.
3.10 Cadmium standard stock solution: weigh accurately 1.000g of cadmium metal (99.99%), dissolve it by adding 20mL of hydrochloric acid (1+1) for several times, add two drops of nitric acid, move it into a 1 000mL volumetric flask, water to the scale and mix uniformly. This solution contains 1.0mg of cadmium per milliliter.
3.11 Cadmium standard working solution: absorb 10.0mL of cadmium standard stock solution every time to 100mL volumetric flask and add nitric acid (0.5mol/L) to the scale. Dilute it like this for several times into a standard working solution of 100.0ng of cadmium per milliliter.
Foreword I
1 Scope
2 Principle
3 Reagents
4 Instruments
5 Analysis Steps
6 Calculation of the Results
7 Precision
8 Principle
9 Reagents
10 Instruments
11 Analysis Steps
12 Calculation of the Results
13 Precision
14 Principle
15 Reagents
16 Instruments
17 Analysis Steps
18 Calculation of the Results
19 Precision
20 Principle
21 Reagents
22 Instrument
23 Analysis Steps
24 Calculation of the Results
25 Precision
26 Principle
27 Reagents
28 Instruments
29 Analysis Steps
30 Calculation of the Results
31 Precision
