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.
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
