GB 13082-1991 English PDF

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GB 13082-1991
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Method for determination of cadmium in feeds
ISSUED ON. JULY 16, 1991
IMPLEMENTED ON. APRIL 01, 1992
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China
Table of Contents
1  Subject Contents and Scope of Application ... 3 
2  Principle ... 3 
3  Reagents and Solutions ... 3 
4  Instruments and Apparatuses ... 4 
5  Preparation of Samples ... 4 
6  Determination Procedures ... 4 
6.1 Sample treatment ... 4 
6.2 Drawing standard curve ... 5 
6.3 Determination ... 5 
7  Determination Results ... 5 
7.1 Computing formula ... 5 
7.2 Result expression ... 6 
7.3 Repeatability ... 6 
Additional Explanation... 6 
Method for determination of cadmium in feeds
1  Subject Contents and Scope of Application 
This standard specifies the method for determination of cadmium in feeds.
This standard is applicable to the determination of cadmium in feeds.
2  Principle 
Decompose the sample by dry ashing method. Under acid conditions and with the
existence of potassium iodide, cadmium ions and iodine ions form a complex, which is
then extraction-separated by methyl isobutyl ketone. Spray the organic phase on
air-acetylene flame to atomize cadmium. Determine its absorbance in relation to the
characteristic resonance-line 228.8 nm. Obtain the content of cadmium by comparing with
the standard series.
3  Reagents and Solutions 
Unless otherwise stated, all reagents used in this standard are analytically pure, and the
water is redistilled water.
3.1 Nitric acid (GB 626), guaranteed.
3.2 Hydrochloric acid (GB 622), guaranteed.
3.3 Potassium iodide solution, 2 mol/L. weigh 332 g of potassium iodide (GB 1272),
dissolve in water, and dilute with water to 1 000 mL.
3.4 Ascorbic acid solution, 5%. weigh 5 g of ascorbic acid (C6H8O6), dissolve in water, and
dilute with water to 100 mL (prepare it before use).
3.5 Hydrochloric acid solution, 1 mol/L. weigh 10 mL of hydrochloric acid (3.2), add 110
mL of water and shake well.
3.6 Methyl isobutyl ketone [CH3COCH2CH(CH3)2, HG 3-1118].
3.7 Cadmium standard stock solution. weigh 0.100 0 g of high purity cadmium metal (Cd,
99.99%), put into a 250 mL Erlenmeyer flask, add 10 mL of 1.1 nitric acid, dissolve
completely by heating on an electric hot plate, dry up, take away and allow to cool down.
Add 20 mL of 1.1 hydrochloric acid and 20 mL of water, dissolve by heating, take away
m – mass of sample, g;
V2 – volume of the sample solution to be tested, mL;
V1 – total volume of sample treatment solution, mL.
7.2 Result expression
For each sample, take two parallel samples to carry out determination, and take their
arithmetic mean as the result.
Express the result to 0.01 mg/kg.
7.3 Repeatability
Two tests are to be conducted by the same analyst on the same sample simultaneously or
successively. The difference between the results.
It shall not exceed 50% of the mean value, if the cadmium content is less than or equal
to 0.5 mg/kg;
It shall not exceed 30% of the mean value, if the cadmium content is greater than 0.5
mg/kg and less than 1 mg/kg;
It shall not exceed 20% of the mean value, if the cadmium content is greater than or
equal to 1 mg/kg.
Additional Explanation. 
This standard was proposed by National Technical Committee on Feeds Industry of
Standardization Administration of China.
This standard was drafted by the Central Laboratory of Huazhong Agricultural University.
The main drafters of this standard are Yuan Junhua and Xia Tao.
GB 13082-1991
GB
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Method for determination of cadmium in feeds
ISSUED ON. JULY 16, 1991
IMPLEMENTED ON. APRIL 01, 1992
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China
Table of Contents
1  Subject Contents and Scope of Application ... 3 
2  Principle ... 3 
3  Reagents and Solutions ... 3 
4  Instruments and Apparatuses ... 4 
5  Preparation of Samples ... 4 
6  Determination Procedures ... 4 
6.1 Sample treatment ... 4 
6.2 Drawing standard curve ... 5 
6.3 Determination ... 5 
7  Determination Results ... 5 
7.1 Computing formula ... 5 
7.2 Result expression ... 6 
7.3 Repeatability ... 6 
Additional Explanation... 6 
Method for determination of cadmium in feeds
1  Subject Contents and Scope of Application 
This standard specifies the method for determination of cadmium in feeds.
This standard is applicable to the determination of cadmium in feeds.
2  Principle 
Decompose the sample by dry ashing method. Under acid conditions and with the
existence of potassium iodide, cadmium ions and iodine ions form a complex, which is
then extraction-separated by methyl isobutyl ketone. Spray the organic phase on
air-acetylene flame to atomize cadmium. Determine its absorbance in relation to the
characteristic resonance-line 228.8 nm. Obtain the content of cadmium by comparing with
the standard series.
3  Reagents and Solutions 
Unless otherwise stated, all reagents used in this standard are analytically pure, and the
water is redistilled water.
3.1 Nitric acid (GB 626), guaranteed.
3.2 Hydrochloric acid (GB 622), guaranteed.
3.3 Potassium iodide solution, 2 mol/L. weigh 332 g of potassium iodide (GB 1272),
dissolve in water, and dilute with water to 1 000 mL.
3.4 Ascorbic acid solution, 5%. weigh 5 g of ascorbic acid (C6H8O6), dissolve in water, and
dilute with water to 100 mL (prepare it before use).
3.5 Hydrochloric acid solution, 1 mol/L. weigh 10 mL of hydrochloric acid (3.2), add 110
mL of water and shake well.
3.6 Methyl isobutyl ketone [CH3COCH2CH(CH3)2, HG 3-1118].
3.7 Cadmium standard stock solution. weigh 0.100 0 g of high purity cadmium metal (Cd,
99.99%), put into a 250 mL Erlenmeyer flask, add 10 mL of 1.1 nitric acid, dissolve
completely by heating on an electric hot plate, dry up, take away and allow to cool down.
Add 20 mL of 1.1 hydrochloric acid and 20 mL of water, dissolve by heating, take away
m – mass of sample, g;
V2 – volume of the sample solution to be tested, mL;
V1 – total volume of sample treatment solution, mL.
7.2 Result expression
For each sample, take two parallel samples to carry out determination, and take their
arithmetic mean as the result.
Express the result to 0.01 mg/kg.
7.3 Repeatability
Two tests are to be conducted by the same analyst on the same sample simultaneously or
successively. The difference between the results.
It shall not exceed 50% of the mean value, if the cadmium content is less than or equal
to 0.5 mg/kg;
It shall not exceed 30% of the mean value, if the cadmium content is greater than 0.5
mg/kg and less than 1 mg/kg;
It shall not exceed 20% of the mean value, if the cadmium content is greater than or
equal to 1 mg/kg.
Additional Explanation. 
This standard was proposed by National Technical Committee on Feeds Industry of
Standardization Administration of China.
This standard was drafted by the Central Laboratory of Huazhong Agricultural University.
The main drafters of this standard are Yuan Junhua and Xia Tao.