GB/T 13085-2018 PDF English
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GB/T 13085: Historical versions
| Standard ID | USD | BUY PDF | Delivery | Standard Title (Description) | Status |
| GB/T 13085-2018 | 105 | Add to Cart | Auto, 9 seconds. | Determination of nitrite in feeds -- Colorimetry method | Valid |
| GB/T 13085-2005 | 239 | Add to Cart | 3 days | Determination of nitrite in feed -- Method using colorimetric analysis | Obsolete |
| GB/T 13085-1991 | 199 | Add to Cart | 2 days | Method for determination of nitrite in feeds | Obsolete |
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GB/T 13085-2018: Determination of nitrite in feeds -- Colorimetry method
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT13085-2018GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 65.120 B 46 Replacing GB/T 13085-2005 Determination of nitrite in feeds - Colorimetry method Issued on. SEPTEMBER 17, 2018 Implemented on. APRIL 01, 2019 Issued by. State Administration for Market Regulation; Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3 1 Scope... 4 2 Normative references... 4 3 Principle... 4 4 Reagents or materials... 4 5 Instruments and equipment... 5 6 Sample... 6 7 Test steps... 6 8 Test data processing... 7 9 Precision... 7Foreword
This Standard was drafted in accordance with the rules given in GB/T 1.1-2009. This Standard replaces GB/T 13085-2005, Determination of nitrite in feed - Method using colorimetric analysis. Compared with GB/T 13085-2005, the main technical changes, except editorial changes, are as follows. -- Modify the detection limit of the method, and add the quantitation limit of the method (see Chapter 1; Chapter 1 of the 2005 edition); -- Modify the preparation method of test solution (see 7.1; 7.1 of the 2005 edition); -- Modify the preparation method of standard curve (see 7.2; 7.2 of the 2005 edition); -- Modify the measurement method of absorbance (see 7.3; 7.3 of the 2005 edition); -- Modify the requirements for precision (see Chapter 9; 8.3 of the 2005 edition). This Standard shall be under the jurisdiction of National Technical Committee 76 on Feed Industry of Standardization Administration of China (SAC/TC 76). Drafting organization of this Standard. Huazhong Agricultural University. Main drafters of this Standard. Qi Desheng, Zhang Niya, He Qiongyu, Wang Jun, Tao Can, Zhu Luoyi. The previous versions – replaced by this Standard – of the standard are. -- GB/T 13085-1991, GB/T 13085-2005. Determination of nitrite in feeds - Colorimetry method1 Scope
This Standard specifies the colorimetry method for the determination of nitrite in feeds. This Standard applies to the determination of nitrite in feed raw materials, compound feeds, concentrated feeds and concentrate supplements. The detection limit of this method is 0.70 mg/kg, and the quantitation limit is 2.0 mg/kg.2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies to this document. For undated references, the latest edition (including any amendment) applies to this document. GB/T 6682, Water for analytical laboratory use - Specification and test methods GB/T 14699.1, Feeding stuffs - Sampling3 Principle
The sample removes protein under weakly alkaline conditions, and the nitrite in the sample reacts with p-aminobenzenesulfonic acid under weakly acidic conditions to form diazo compounds, which are then coupled with N-1-naphthylethylenediamine to form purple compounds.4 Reagents or materials
Unless otherwise specified, only use reagents confirmed to be of analytical grade in the analysis. 4.1 Water. grade-II water as specified in GB/T 6682. 4.2 Dilute hydrochloric acid solution. Take 5 mL of hydrochloric acid; add it to a 100 mL volumetric flask; use water to dilute to a constant volume; mix well. 4.7 Acetic acid solution. Measure 600 mL of glacial acetic acid in a 1 000 mL volumetric flask; use water to dilute to the mark; mix well. 4.8 P-aminobenzenesulfonic acid solution. Weigh 5.0 g of p-aminobenzenesulfonic acid; dissolve it in 700 mL of water and 300 mL of glacial acetic acid; mix well; store in a brown bottle. The validity period is 7 days. 4.9 N-1-Naphthylethylenediamine solution. Weigh 0.1 g of N-1- naphthylethylenediamine; add acetic acid solution (4.7) to dissolve and dilute to a constant volume of 100 mL; mix well; put it in a brown bottle; store it in a refrigerator at 4 °C ~ 10 °C. The validity period is 7 days. 4.10 Color-developing agent. Mix equal volumes of p-aminobenzenesulfonic acid solution (4.8) and N-1-naphthylethylenediamine solution (4.9) before use. 4.12 Sodium nitrite standard working solution (5.0 μg/mL). Accurately pipette 1.00 mL of sodium nitrite standard stock solution (4.11) into a 100 mL volumetric flask; add water to dilute to a constant volume to the mark; mix well. Prepare when necessary.5 Instruments and equipment
5.1 Spectrophotometry. 5.2 Water bath. The temperature control range is 25 °C ~ 100 °C; the temperature control accuracy is ±1 °C.6 Sample
Collect samples according to GB/T 14699.1, and prepare samples according to GB/T 20195.7 Test steps
7.1 Preparation of test solution Perform two tests in parallel. Weigh about 5 g of sample, accurate to 0.001 g; place it in a 200 mL conical flask; add 70 mL of water and 1.2 mL of sodium hydroxide solution (4.6); mix well; use sodium hydroxide solution (4.6) to adjust the pH to 8 ~ 9; add 10 mL of zinc sulfate solution (4.5); 7.2 Preparation of nitrite standard curve Accurately pipette 0 mL, 0.4 mL, 0.8 mL, 1.2 mL, 1.6 mL and 2.0 mL of sodium nitrite standard working solution (4.12), respectively, into 25 mL brown volumetric flasks (equivalent to 0 μg, 2 μg, 4 μg, 6 μg, 8 μg, 10 μg of sodium nitrate); after respectively adding 4.5 mL of ammonium chloride buffer solution (4.4) and 2.5 mL of acetic acid solution (4.7), immediately add 5.0 mL of color-developing agent (4.10); 7.3 Determination of test solution Pipette two parts of 10.0 mL test solution (7.1) into 25 mL volumetric flasks a and b, respectively. Add 4.5 mL of ammonium chloride buffer solution (4.4) and 2.5 mL of acetic acid solution (4.7) into the volumetric flask a; then, use water to dilute to the mark; mix well.8 Test data processing
The content of nitrite in the sample is calculated according to the mass fraction w of sodium nitrite (NaNO2); the value is expressed in milligrams per kilogram (mg/kg), and calculated according to Formula (1).9 Precision
The absolute difference between two independent test results obtained under repeatability conditions and their arithmetic mean is not more than 10% of the mean. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
