GB 5009.15-2023National food safety standard - Determination of cadmium in foods (English PDF)

3.1 Reagents

3.2 Preparation of Reagents

3.3 Reference Material

Cadmium chloride (CdCl2  2.5H2O, CAS No.. 7790-78-5). purity > 99.99%, or a standard

substance certified by the state and awarded a reference material certificate.

3.4 Preparation of Standard Solutions

3.4.1 Cadmium standard stock solution (100 mg/L). accurately weigh-take 0.2032 g of

cadmium chloride, use a small amount of nitric acid solution (1 + 9) to dissolve it, transfer it

into a 1,000 mL volumetric flask. Add water to the scale and evenly mix it. The mass

concentration of cadmium in this solution is 100 mg/L.

3.4.2 Cadmium standard intermediate solution (100 g/L). accurately draw 1.00 mL of

cadmium standard stock solution (100 mg/L) into a 10 mL volumetric flask, add nitric acid

solution (5 + 95) to the scale, and evenly mix it.

3.4.3 Cadmium standard series of working solutions. respectively and accurately draw 0 mL,

0.200 mL, 0.500 mL, 1.00 mL, 2.00 mL and 4.00 mL of cadmium standard intermediate

solution (100 g/L) into a 100 mL volumetric flask.

4.1 Atomic absorption spectrometer. equipped with graphite furnace atomizer and cadmium

hollow cathode lamp.

4.2 Electronic balance. with a division value of 0.1 mg and 1 mg.

5.1 Specimen Preparation

5.1.1 Solid-state samples

5.1.2 Liquid samples

For samples, such as. soft drinks and condiments, etc., evenly shake them.

5.1.3 Semi-solid samples

Evenly mix them.

5.2 Test Conditions of the Method

5.2.1 Specimen pre-treatment

5.3 Reference Conditions of Instruments

See Table A.2 for instrument operating conditions.

5.4 Drawing of Standard Curve

In accordance with the mass concentration from low to high, respectively take 10 L of the

standard series of solutions and 5 L of the ammonium dihydrogen phosphate - palladium

nitrate mixed solution (select the optimal sample injection volume in accordance with the

instrument used), meanwhile, inject it into the graphite tube.

5.5 Determination of Specimen Solution

Under the same test conditions as the standard curve, draw 10 L of blank solution or specimen

digestion solution, and 5 L of the ammonium dihydrogen phosphate - palladium nitrate mixed

solution (select the optimal sample injection volume in accordance with the instrument used),

meanwhile, inject it into the graphite tube.

0.001 mg/L.

Appendix A

Microwave Digestion Temperature Rise Program and Instrument

Reference Conditions of Graphite Furnace Atomic Absorption

Spectrometry

A.1 The microwave digestion temperature rise program is shown in Table A.1.

Table A.1 -- Microwave Digestion Temperature Rise Program

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