GB/T 13082-2021 English PDF (GB 13082-1991, GB/T 13082-1991)

BASIC DATA
Standard ID	GB/T 13082-1991 (GB/T13082-1991)
Description (Translated English)	Method for determination of cadmium in feeds
Sector / Industry	National Standard (Recommended)
Classification of Chinese Standard	B46
Classification of International Standard	65.12
Word Count Estimation	3,373
Date of Issue	1991/7/6
Date of Implementation	1992/4/1
Drafting Organization	Central Laboratory of Huazhong Agricultural University
Summary	This standard specifies the method for the determination of cadmium in feed. This standard applies to the determination of cadmium in feed.

GB/T 13082-2021 NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 65.120 CCS B 46 Replacing GB/T 13082-1991 Determination of cadmium in feeds ISSUED ON: NOVEMBER 26, 2021 IMPLEMENTED ON: JUNE 01, 2022 Issued by: State Administration for Market Regulation; Standardization Administration of PRC. Table of Contents Foreword ... 3 1 Scope ... 4 2 Normative references ... 4 3 Terms and definitions... 4 4 Principles ... 4 5 Reagents or materials ... 5 6 Instruments and equipment ... 6 7 Samples ... 6 8 Test procedures ... 7 9 Processing of test data ... 10 10 Precision ... 11 Determination of cadmium in feeds 1 Scope This document describes flame atomic absorption spectrometry and graphite furnace atomic absorption spectrometry, for the determination of cadmium in feed. This document applies to the determination of cadmium, in compound feeds, concentrated feeds, concentrate supplements, additive premixed feeds, feed additives, feed ingredients. In this document, when the sampling amount is 5 g and the constant volume is 50 mL, the detection limit of flame atomic absorption spectrometry is 0.08 mg/kg AND the quantification limit is 0.20 mg/kg. When the sampling amount is 0.5 g and the constant volume is 25 mL, the detection limit of graphite furnace atomic absorption spectrometry is 0.002 mg/kg AND the quantification limit is 0.05 mg/kg. 2 Normative references The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, for dated references, only the version corresponding to the date applies to this document; for undated references, the latest version (including all amendments) is applicable to this document. GB/T 6682 Water for analytical laboratory use - Specification and test methods GB 6819-2004 Dissolved acetylene GB/T 20195 Animal feeding stuffs - Preparation of test samples 3 Terms and definitions There are no terms and definitions, that need to be defined in this document. 4 Principles After dry ashing or wet digestion (microwave digestion), or hydrochloric acid dissolution, the specimen is introduced into the flame or graphite furnace atomizer of atomic absorption spectrophotometer, to measure the absorbance value at a wavelength of 228.8 nm. Within a certain concentration range, the cadmium concentration is proportional to its absorbance value; the standard curve is used for calibration and quantitative. 5 Reagents or materials Warning: When using various strong acids, it shall be carried out in a fume hood; when using perchloric acid for digestion, be careful not to burn it dry, to prevent explosion. Unless otherwise specified, only analytical grade reagents are used. 5.1 Water: GB/T 6682, grade 1. 5.2 Nitric acid: Excellent grade pure. 5.3 Hydrochloric acid: Excellent grade pure. 5.4 Perchloric acid: Excellent grade pure. 5.5 Hydrochloric acid solution (6 mol/L): Dilute 500 mL of hydrochloric acid (5.3) to 1000 mL. Mix well. 5.6 Nitric acid solution: Dilute 10 mL of nitric acid (5.2) to 1000 mL. Mix well. 5.7 Nitric acid solution (6 mol/L): Dilute 43 mL of nitric acid (5.2) to 100 mL. Mix well. 5.8 Palladium nitrate solution (2 mg/mL): Weigh 0.20 g of palladium nitrate. Use water to dissolve it. Dilute it to 100 mL. Mix well. 5.9 Ammonium dihydrogen phosphate solution (10 mg/mL): Weigh 1.00 g of ammonium dihydrogen phosphate. Use water to dissolve it. Dilute it to 100 mL. Mix well. 5.10 Cadmium standard stock solution (1 mg/mL): Accurately weigh 1.0000 g of metal cadmium (certified reference material, purity 99.99%), into a 250 mL conical flask. Add 10 mL of nitric acid solution (5.7). Heat on an electric hot plate, to dissolve all. Then, transfer to a 1000 mL volumetric flask. Add water to the mark. Mix well. Store it in polyethylene bottles at 4 °C; the validity period is 6 months. OR otherwise purchase certified standard solutions. 5.11 Cadmium standard intermediate solution I (10 μg/mL): Accurately pipette 1 mL of cadmium standard stock solution (5.10), into a 100 mL volumetric flask. Use nitric acid solution (5.6), to dilute it to the mark. Mix well. The valid period is 1 month. 5.12 Cadmium standard intermediate solution II (100 μg/L): Accurately pipette 1 mL of cadmium standard intermediate solution I (5.11), into a 100 mL volumetric flask. Use nitric acid solution (5.6), to dilute it to the mark. Mix well. Prepare it before use. 8 Test procedures 8.1 Preparation of specimen solution 8.1.1 Dry ashing method It is suitable for compound feed, concentrated feed, concentrate supplement, pre-mixed feed containing organic matter additives, feed additives, feed raw materials. Do two tests in parallel. Weigh 5 g of the specimen (accurate to 0.01 g), in a porcelain crucible. Place it on an adjustable electric hot plate or an adjustable electric furnace, to slowly heat and carbonize it, until it is smokeless. Then transfer it to a 500 °C muffle furnace, for ashing for 5 hours, until the specimen turns white or grey-white, without carbon particles. If a small amount of carbon particles is found, nitric acid solution (5.7) can be added to wet the residue. Move the porcelain crucible to an adjustable electric hot plate or adjustable electric furnace, to dry on a small fire. Then move it into a muffle furnace, to continue ashing, until the specimen is white or grey-white, without carbon particles. Take out the crucible. Cool to room temperature. Absorb 5 mL of hydrochloric acid solution (5.5). Add it dropwise to the porcelain crucible. Turn it while adding, until no bubbles overflow from the solution. Add the remaining hydrochloric acid solution. Then add 5 mL of nitric acid solution (5.7). Move the porcelain crucible to the adjustable electric heating plate or adjustable electric furnace. Slowly heat it, until the digestion solution reaches 2 mL ~ 3 mL (be careful to prevent splashing). Remove it. Cool it to room temperature. Transfer the digestion solution into a 50 mL volumetric flask. Use a small volume of water, to rinse the wall of the porcelain crucible several times. Incorporate it into the volumetric flask. Add water to the mark. Shake well. Filter it. Prepare for use. At the same time, do a blank test. 8.1.2 Wet digestion method It is suitable for additive premixed feed which contain more organic matter, feed additives, feed raw materials. Do two tests in parallel. Weigh 1 g of the specimen (accurate to 0.0001 g) into the digestion tube. Add a small amount of water to wet it. Add 10 mL of nitric acid (5.2). Put it in a fume hood. Let it stand for 2 hours. Then add 5 mL of perchloric acid (5.4). Use small fire, to heat it on an adjustable electric heating plate or an adjustable electric furnace, which is below 250 °C, for digestion, until the digestion solution emits white smoke. Remove it and cool it. Transfer the digestion solution into a 50 mL volumetric flask. Use a small volume of water, to rinse the digestion tube several times. Incorporate it into the volumetric flask. Add water to the mark. Shake well. Filter it. Prepare for use. At the same time, do a blank test. ......

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 and allow to cool down. Then, transfer to a 1 000 mL volumetric flask, dilute with water to the scale and shake well. Each milliliter of this solution is equivalent to 100 μg of cadmium. 3.8 Cadmium standard intermediate solution: pipette 10 mL of cadmium standard stock solution (3.7) into a 100 mL volumetric flask, dilute with 1 mol/L hydrochloric acid (3.5) to the scale and shake well. Each milliliter of this solution is equivalent to 10 μg of cadmium. 3.9 Cadmium standard working solution: pipette 10 mL of cadmium standard intermediate solution (3.8) into a 100 mL volumetric flask, dilute with 1 mol/L hydrochloric acid (3.5) to the scale and shake well. Each milliliter of this solution is equivalent to 1 μg of cadmium. 4 Instruments and Apparatuses 4.1 Analytical balance, accuracy of 0.000 1 g. 4.2 Muffle furnace. 4.3 Atomic absorption spectrophotometer. 4.4 Hard beaker, 100 mL. 4.5 Volumetric flask, 50 mL. 4.6 Colorimetric tube with stopper, 25 mL. 4.7 Measuring pipets, 1, 2, 5 and 10 mL 4.8 Transfer pipets, 5, 10, 15 and 20 mL. 5 Preparation of Samples Collect at least 2 kg of representative feeds sample, divide into about-250 g by quartation, put through a 1 mm sieve, mix well and seal in an airtight wide-necked sample bottle to prevent deterioration. Store at low temperature for later use. 6 Determination Procedures 6.1 Sample treatment Accurately weigh 5~10 g of sample, put into a 100 mL hard beaker (4.4), place in the Muffle furnace (4.2), and leave the furnace door open slightly. Start from a low temperature, heat up to 200℃ and hold for 1 h, then heat up to 300℃ and hold for 1 h, finally heat up to 500℃ and burn for 16 h until the sample becomes white or gray and does not contain any carbon granules. ......