GB/T 13090-2025 (GB/T 13090-2006) PDF EnglishUS$125.00 · In stock · Download in 9 seconds
GB/T 13090-2006: Determination of HCH and DDT in feeds Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure Status: Valid GB/T 13090: Historical versions
Similar standardsGB/T 13090-2006: Determination of HCH and DDT in feeds---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/GBT13090-2006NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 65.120 B 46 Replacing GB/T 13090-1999 Determination of HCH and DDT in feeds ISSUED ON: DECEMBER 12, 2006 IMPLEMENTED ON: MARCH 01, 2007 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC; National Standardization Administration. Table of ContentsForeword ... 3 1 Scope ... 4 2 Normative references ... 4 3 Principle of the method ... 4 4 Reagents ... 5 5 Instruments and equipment ... 7 6 Preparation of specimens ... 7 7 Analysis steps ... 7 8 Calculation and presentation of results ... 9 9 Repeatability ... 11 Determination of HCH and DDT in feeds1 ScopeThis standard specifies the gas chromatography method for the determination of HCH and DDT residues in feed. This standard is applicable to the determination of HCH, DDT isomers and derivatives residues in compound feed, plant materials and fish meal. This standard is not applicable to the detection of products containing organochlorine pesticide heptachlor.2 Normative referencesThe clauses in the following documents become clauses of this standard through reference in this standard. For all dated references, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all undated references, the latest versions are applicable to this standard. GB/T 6682 Water for analytical laboratory use - Specification and test methods GB/T 14699.1 Feeding stuffs - Sampling GB/T 20195 Animal feeding stuffs - Preparation of test samples3 Principle of the methodHCH and DDT in the sample are extracted with a mixed solvent of n-hexane containing a small amount of acetone, filtered and fixed to volume; then a certain amount of extract is drawn out from it. After purification, the n-hexane eluent is concentrated and made to volume; then directly injected into the gas chromatograph for detection by an electron capture detector; the external standard method is used for qualitative and quantitative analysis. The minimum detection limit of each compound in this method is shown in Table 1. Note: HCH and DDT standard solutions are toxic and must be soaked in concentrated potassium hydroxide or hexavalent chromium acid before washing.5 Instruments and equipmentLaboratory commonly used instruments and equipment and the following instruments and equipment. 5.1 Analytical balance: The sensitivity 0.0001 g and sensitivity 0.00001 g. 5.2 Electric oscillator and ultrasonic extractor. 5.3 Cylindrical funnel: Inner diameter 2 cm, height 5 cm. 5.4 Chromatographic column: Inner diameter 8 mm ~ 10 mm, length 15 cm ~ 20 cm. The top end is equipped with a cylindrical funnel storage tank, which has a capacity of about 30 mL. 5.5 Carrier gas: High purity nitrogen 99.99%. 5.6 Gas chromatograph: Equipped with electron capture detector. 5.7 Chromatographic column: Glass filling column: 2 m × φ3 mm, filled with 1.5% OV-17+2.0% QF-1/GCQ 80 mesh ~ 100 mesh or 1.6% OV-17+6.4% OV-210/Chromosorb W-HP 80 mesh ~ 100 mesh. Capillary chromatographic column: DB-5 column length: 25 m or 50 m; inner diameter: 0.32 mm; film thickness: 0.25 μm. Or capillary column with medium polarity stationary phase (such as: SE-30, SE-54, OV-17).6 Preparation of specimensSampling shall be in accordance with GB/T 14699.1. The specimen preparation shall be in accordance with GB/T 20195.7 Analysis steps7.1 Debugging of gas chromatograph 7.1.1 Chromatographic conditions Column type: Packed column Capillary column Detector temperature: 250 °C 300 °C Inlet temperature: 230 °C 270 °C mL brown volumetric flask. Wash the residue to make up the volume. Shake the extract well and set aside. 7.3 Purification Method 1: Take 5 mL of the extract and pass it through the chromatography column (5.4); insert a little cotton (4.10) into the column; add about 0.5 cm thick anhydrous sodium sulfate (4.8); then add acidified diatomaceous earth [place 1.5 g of diatomaceous earth or celite545 (4.9) in a glass mortar; add 0.6 mL of sulfuric acid (4.6); mix well]; immediately put it into the column; compact it; then add about 1 cm thick anhydrous sodium sulfate (4.8) on top. Put 5.00 mL of the extract (7.2) on the loaded chromatography column; elute it with n-hexane (4.2) continuously at a speed of 60 drops/min ~ 90 drops/min; collect 10 mL of the eluent; blow it to nearly dry with nitrogen; make up to 2 mL with n-hexane, which is the purification solution for the sample to be tested. Method 2: Take 5 mL of the extract in a centrifuge tube; add 0.5 mL of concentrated sulfuric acid; shake for 0.5 min; centrifuge at 3000 r/min for 10 min; take the supernatant to repeat purification 1 ~ 2 times until colorless; centrifuge at 3000 r/min for 10 min; wash the supernatant twice with 2% sodium sulfate aqueous solution; discard the water layer; blow it to nearly dryness with nitrogen; make up to 2 mL with n-hexane, which is the sample purification solution to be tested. 7.4 Gas chromatography determination Inject 1 μL ~ 5 μL of the sample purification solution (7.3) into the debugged gas chromatograph (7.1); identify the compound according to the retention time; finally record its peak area (As). 7.5 Blank test In the absence of feed samples, follow the steps 7.2, 7.3, 7.4. The blank test values of various compounds shall be lower than the minimum detection limit of the method (see Table 1). If it is higher than the minimum detection limit of the method, the background value shall be deducted.8 Calculation and presentation of results8.1 Calculation of results 8.1.1 Single-point correction method The pesticide residue w in the specimen is expressed as mass fraction (μg/kg), which is calculated according to formula (1): Wherein: As - Peak area or peak height of the component in the specimen purification solution, in microvolt seconds or millimeters (µV • s or mm); Ast - Average peak area or peak height of the component in the standard solution with a peak area similar to As, in microvolt seconds or millimeters (µV • s or mm); mst - Mass of the component in the standard solution corresponding to Ast, in picograms (pg); m - Specimen mass, in grams (g); V - Total volume of specimen purification solution, in milliliters (mL); Vi - Injection volume of specimen purification solution, in microliters (μL). Note: When the background value of the component in the blank test is higher than the minimum detection limit of the method, As shall be deducted from the background value. 8.1.2 Multi-point calibration method After adding the mixed standard solutions of series No.1 ~ No.6, calculate the regression equation of the component peak area or peak height and the component mass: Where: Ast - Peak area or peak height of the component in the standard solution, in microvolt seconds or millimeters (µV • s or mm); mst - Mass of the component in the standard solution, in picograms (pg); a - Slope of the calibration curve of the component, in microvolt seconds per picogram or millimeter per picogram (µV • s /pg or mm/pg); b - Intercept of the calibration curve of the component, in microvolt seconds or millimeters (µV • s or mm). Therefore: Where: ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
