GB 14883.6-2016 English PDFUS$219.00 · In stock
Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB 14883.6-2016: National Food Safety Standard -- Determination of radioactive substances radium - 226 and radium - 228 in food Status: Valid GB 14883.6: Historical versions
Basic dataStandard ID: GB 14883.6-2016 (GB14883.6-2016)Description (Translated English): National Food Safety Standard -- Determination of radioactive substances radium - 226 and radium - 228 in food Sector / Industry: National Standard Classification of Chinese Standard: C53 Classification of International Standard: 67.040 Word Count Estimation: 11,110 Date of Issue: 2016-08-31 Date of Implementation: 2017-03-01 Older Standard (superseded by this standard): GB 14883.6-1994 Regulation (derived from): Announcement of the State Administration of Public Health and Family Planning 2016 No.11 Issuing agency(ies): National Health and Family Planning Commission of the People's Republic of China, State Food and Drug Administration GB 14883.6-2016: National Food Safety Standard -- Determination of radioactive substances radium - 226 and radium - 228 in food---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order. (Food safety national standard - Determination of radioactive substances radium - 226 and radium - 228 in foods) National Standards of People's Republic of China National Food Safety Standard Determination of radioactive materials radium-226 and radium - 228 Issued on.2016-08-31 2017-03-01 implementation People's Republic of China National Health and Family Planning Commission released ForewordThis standard replaces GB 14883.6-1994 "Food Examination of radioactive materials radium-226 and radium -228 determination." This standard compared with GB 14883.6-1994, the main changes are as follows. --- Standard name was changed to "national food safety standards in food radioactive material radium-226 and radium -228 determination"; --- National food safety standards in accordance with the format of the text has been adjusted; --- Sort out and changed the order of some of the terms and formulas; --- Fixed Appendix A for errors. National Food Safety Standard Determination of radioactive materials radium-226 and radium - 2281 ScopeThis standard applies to (226Ra) and radium -228 (228Ra) Determination of radium-226 in various foods. Determination of radium-226 Principle 2 Food ash by alkali fusion, with hydrochloric acid to dissolve the flooding after the insolubles to lead, barium carrier, barium -133 (133Ba) as a tracer, sulfuric acid Concentrated radium salt precipitation, precipitation with disodium edetate (EDTA-2Na) was dissolved alkaline storage in the diffuser to emanation method measuring sub Radon -222 (222Rn), calculated 226Ra radioactivity concentration.3 Reagents and materialsUnless otherwise indicated, the methods used were of analytical grade reagents and water as a water GB/T 6682 regulations. 3.1 Reagents 3.1.1 anhydrous sodium carbonate (Na2CO3). 3.1.2 sulfuric acid (H2SO4). 3.1.3 hydrochloric acid (HCl). 3.1.4 Sodium peroxide (Na2O2). 3.1.5 sodium hydroxide (NaOH). 3.1.6 disodium edetate (C10H14N2Na2O8 · 2H2O). Also known as EDTA-2Na. 3.2 reagent preparation 0.2mol/LEDTA-2Na alkaline solution. dissolve 74g disodium ethylenediaminetetraacetate and 15g of sodium hydroxide in water and dilute to 1L. 3.3 Standard 133Ba tracer. 133Ba (NO3) 2, radioactivity concentration of about 104 counts/(min · mL). 3.4 Standard Solution 3.4.1 6mgBa2/mL barium carrier solution. Weigh 10.7g of barium chloride (BaCl2 · 2H2O), dissolved in 1% nitric acid and diluted to 1L. 3.4.2 50mgPb2/mL lead carrier solution. Weigh 80.0g of lead nitrate [Pb (NO3) 2], dissolved in 1% nitric acid and diluted to 1L. 3.4.3 226Ra standard solution. liquid 226Ra standard solution or a standard radium powder accurately formulated as a 1% nitric acid. Radioactive concentration 0.1Bq226Ra/mL ~ 1Bq226Ra/mL.4 instruments and equipment4.1 radon thorium Analyzer. FD-125-type or other types, with appropriate scaling and flicker chamber that the background count rate should be no more than 2 meters Number/min. 4.2 γ radioactivity measuring devices. Universal γ probe connector scaler. Part of the probe shielded with lead room. Flashing 4.3 Room. volume 500mL. 4.4 Glass diffuser. the volume of 100mL. Designed specifically fired [see Figure 1a)] or 100mL large tube Replacement [see Figure 1b)]. FIG. 1 glass diffuser 4.5 iron or nickel crucible crucible or high-alumina crucible. 50mL. 4.6 vacuum suction pump. Step 5 Analysis 5.1 Instrument commissioning Radon and γ radioactive thorium analyzer measurement devices should choose to work in advance and screening threshold voltage. The former uses radon source, which allows 133Ba radioactive tracers used for debugging. The operating voltage from the measured curve plateau, usually combined with the background count rate in the range of 1/3 to 1/2 to select; in the selected operating voltage Under the screening threshold from the measured background count rate - the screening threshold relationship to select the best value on the curve. 5.2 Determination of scintillation cell conversion coefficient k value Conversion coefficient k value represents the net count rate per unit on behalf of 226Ra Bq number of its measurement method is as follows. the pre-evacuated scintillation Figure 2 rooms connected. The diffuser filled with a known amount of 226Ra (1Bq ~ 10Bq) standard solution, radon ventilation after 10min drive when certain archives between. First opened three clips on the right, and then slowly release the flashing between the chamber and a drying tube clamp screw to control the spread of the bubble countable. Using a scintillation In addition to the negative pressure chamber slowly inhaled air radon, so the diffuser into scintillation radon chamber until no bubbles up. After standing at room flashes 3h radon thorium Measuring analyzer. Blinking into the room before the radon measurements should be evacuated background. After the sample measurement chamber flashing immediately with vacuum pump to Minimize flicker room floor to prevent contamination. It requires accurate determination of when to use each of the scintillation chamber itself k value, the actual monitoring in general also You may use a flashing chamber measured to calculate the average value of k, k values are calculated in the formula (1). Figure 2 222Rn transfer device k = A '(1-e-λT') N1'-N0 (1) Where. k --- scintillation cell conversion factor for 1 instrument response counts/min 226Ra Bq considerable number of counts per unit of shellfish separable (Bq · min/count); A '--- standard source 226Ra content unit is becquerel (Bq); λ --- radon decay constant, units per day (d-1), radon decay and growth of Appendix A by Richard; T '--- radium standard source storage time in days (d) and hours (h); N1 '--- radium standard source count rate in units of counts per minute (cpm); N0 --- flashes when the standard source chamber measuring the background count rate in units of counts per minute (cpm). 5.3 Sampling and pretreatment Sampling and pretreatment according to the provisions of GB 14883.1. 5.4 Preparation of sample and assay 5.4.1 Weigh 1g ~ 4g (accurate to 0.001g) food gray iron crucible, plus lead, barium carrier solution of 2.00mL (test sample recovery Product ash also joined 1.00mL133Ba tracer). So full of ash after wetting and drying in infrared light. After a glass rod mashed were added 2g Anhydrous sodium carbonate, 5g of sodium hydroxide and sodium peroxide 8g. Stir cover 2g sodium peroxide on the surface, put warmed to 650 ℃ ~ Muffle furnace 700 ℃ in molten 7min ~ 10min, so that the melt-shaped dark red uniform. 5.4.2 Remove the crucible coolish, the outer wall of the crucible soaked in cold water quenching. Remove the crucible, placed in hot water containing 200mL 600mL Beaker and carefully down, immersion heated water to the crucible and heated. After the reaction is complete, remove the crucible after prolapse frit, washed with water, the crucible, and then less The amount of diluted hydrochloric acid solution and water cleaned inside and outside walls of the crucible. Washings were combined in a beaker, stir well. 5.4.3 filtered, washed with hot fractional 50mL 1% sodium carbonate solution was precipitated, filtrate and washings were discarded. 30mL1.1 with hydrochloric acid Precipitates were dissolved in 300mL beaker was filtered and the filtrate was washed with water to a white paper. Add water to about 250mL, on a hot plate heated to boiling. 5mL1.1 sulfuric acid was added dropwise with stirring and cooling. Place more than 4h. Dumping 5.4.4 The supernatant was fully transferred to 50mL centrifuge tubes, centrifuged, the supernatant was discarded. With nitric acid 10mL, 40mL each wash water sink Lake 1, discard the eluate. Plus 15mL0.2mol/LEDTA-2Na alkaline solution (3.2) into a centrifuge tube, heated in a water bath, stirring occasionally Until dissolved. Solution was transferred to the diffuser. A small amount of water tubes, combined eluate to diffusion, control volume of solution volume diffuser 1/3 ~ 1/2. 5.4.5 Used diffusion through the air vent 10min charcoal tube to get rid of the remnants of radon. Archive and record the time, the best seal 12d the above. 5.4.6 flashing chamber is evacuated, after measuring the background, in the same manner 5.2 Transfer diffuser sample radon gas into the chamber flashes, measured after standing 3h Sample radioactivity. 5.5 Determination of the chemical recovery The sample solution is added 133Ba tracer scale fully transferred to 40mL small beaker, diluted with water to the mark. Use containing the same volume Water containing tracer 1mL133Ba same scale small beaker determination of chemical recovery in γ radioactivity measuring device. 5.6 blank test Of the reagents should be measuring reagent of the background. In addition to the sample without ash, the other with the same determination of sample analysis.6 expression analysis(2) calculate the concentration of radioactivity in food 226Ra by the formula. A = kM WR ( N1-N3 1-e-λT N2-N4 1-eλT0) (2) Where. A --- foods 226Ra concentration of radioactivity in units of becquerels per kilogram (Bq/kg); k --- scintillation cell conversion factor with the formula (1); M --- fresh ash, in units of grams per kilogram (g/kg); W --- analysis gray mass in grams (g); R --- radium chemical recovery; N1 --- sample total count rate in units of counts per minute (cpm); N3 --- sample chamber flicker measurement of the background count rate in units of counts per minute (cpm); λ --- radon decay constant, with the formula (1); T --- sample storage time in days (d) and hours (h); N2 --- reagent blank total count rate in units of counts per minute (cpm); When N4 --- scintillation cell measuring reagent blank background count rate in units of counts per minute (cpm); T0 --- reagent blank storage time in days (d) and hours (h).7 OtherUnder typical conditions, the detection limit of the method was 4.3 × 10-3Bq/g ash. Determination of radium - 228 Principle 8 Food ash by alkali fusion, after the flooding was filtered, the precipitate dissolved in hydrochloric acid. Barium, lead sulphate co-precipitated double carrier concentration of radium. 2d place After using two - (2-ethylhexyl) phosphoric acid - heptane extraction of 228Ra daughter actinium -228 (228Ac), by measuring the β radioactivity 228Ac calculated 228Ra radioactivity concentration.9 Reagents and materials9.1 Reagents 9.1.1 glacial acetic acid (C2H4O2). 9.1.2 anhydrous sodium carbonate, sulfuric acid, hydrochloric acid, sodium peroxide, sodium hydroxide with the 3.1.1 - 3.1.5. 9.1.3 diethylenetriamine pentaacetic acid (C14H23N3O10). 9.1.4 monochloroacetic acid (C2H3ClO2). 9.1.5 heptane (C7H16). 9.1.6 two - (2-ethylhexyl) phosphoric acid (C16H35O4P). also known as DEHPA. 9.1.7 ammonium oxalate [(NH4) 2C2O4]. 9.1.8 Sodium acetate (CH3COONa). 9.2 reagent preparation 9.2.1 0.17mol/LDTPA solution. Weigh 76g diethylenetriaminepentaacetic acid and 32g of sodium hydroxide dissolved in 1L of water, neutralized with sodium hydroxide Or perchloric acid to adjust the pH to 10. 9.2.2 DTPA washing solution. Weigh 100g monochloroacetic acid, 10g diethylenetriaminepentaacetic acid and 32g of sodium hydroxide dissolved in 1L of water. pH It should be 3. 9.2.3 15HPA- heptane solution. 150mLDEHPA with 850mL heptane (or hexane) were mixed. Washing liquid with 200mL (Equal volume mixture of 2mol/L diammonium hydrogen citrate and concentrated aqueous ammonia) twice, washed 200mL4mol/L nitric acid solution and then 2 times, Washed once placed aside. Before using the washing solution was washed with DTPA 1 times. 9.2.4 0.2mol/L ammonium oxalate solution. Weigh 24.8g ammonium oxalate is dissolved in an appropriate amount of water, diluted with water to 1L. 9.2.5 1mol/L sodium sulfate solution. Weigh 142g sodium sulfate dissolved in an appropriate amount of water, diluted with water to 1L. 9.2.6 60% sodium acetate solution. Weigh 60g of anhydrous sodium acetate is dissolved in an appropriate amount of water, diluted with water to 100mL. 9.2.7 2mol/L monochloroacetic acid. Weigh 188g acid is dissolved in a suitable amount of water, diluted with water to 1L. 9.2.8 0.2mol/LEDTA-2Na alkaline solution. Same as 3.2. 9.3 Standard 133Ba tracer. Same as 3.3. 9.4 Standard Solution 9.4.1 Lead carrier solution. with 3.4.2. 9.4.2 barium carrier solution. with 3.4.1. 9.4.3 cerium carrier solution. cerium nitrate, 5mgCe3/mL, in the presence of an acid, and extracted with DEPHA purification. Purification Methods. cerium carrier solution .2mol/L acid .DEHPA- a heptane mixed 4.1.2 volume ratio of extraction 15min. The organic phase was washed with an equal volume of DTPA extraction wash 2min, discarding the aqueous phase with an equal volume of 0.5mol/L nitric acid was back extracted 15min. 9.4.4 228Ra standard solution. radioactive equilibrium solution of thorium. Per mg of thorium and radioactive equilibrium 4.035Bq228Ra from thorium content meter Operators 228Ra accurate content. 10 instruments and equipment 10.1 γ radioactivity measuring device and the Iron Crucible. with 4.2 and 4.5. 10.2 low background β measuring instrument. probe diameter of not less than 2cm, background count no more than 1/min. 11 analysis steps 11.1 228Ac counting efficiency and determination of total self-absorption correction factor Standard solution with 228Ra determined experimentally, that is filled with 100mL0.5mol/L hydrochloric acid solution 300mL beaker known quasi 228Ra standard solution correct amount was added to each of lead and barium carrier solution 2mL and 1mL133Ba tracer. Add water to about 200mL, electric On boil, stirring dropping 5mL1.1 sulfuric acid, cooled, and placed more than 4h, the following samples analyzed by the same 11.3.2 start measuring step, Measuring, according to equation (3) to calculate the total correction factor E. While supervision by 90Sr-90Y source measurement. E = N'eλ (t3'-t2 ') A'R'b ' (3) Where. E --- instrument of 228Ac counting efficiency and total self-absorption correction factor; N '--- E net count rate measured in units of counts per minute (cpm); λ --- 228Ac decay constant, in units of one-half hour (h-1), λ = 0.693/T 0, T0 is the half-life of 228Ac, 6.13h; t3'-t2 '--- E assay 228Ac decay time in hours (H); The amount of A '--- E added 228Ra when measured in units of decays per minute (dpm); Radium Chemical recovery when R '--- E Determination; b '--- E growth when measured coefficient of 228Ac. 11.2 Sampling and pretreatment Sampling and pretreatment according to the provisions of GB 14883.1. 11.3 Sample preparation and assay 11.3.1 Weigh 4g (accurate to 0.001g) in a sample of gray iron crucible, plus lead, barium carrier solution of 2mL (radium recovery test sample ash Also joined 1.00mL133Ba tracer), so that the whole ash after wetting and drying in infrared light. Mashed with a glass rod peroxide were added 2g Sodium, 5g and 8g sodium hydroxide, sodium peroxide, stir evenly cover the surface 2g sodium peroxide, add warmed to 650 ℃ ~ 700 ℃ Muffle furnace melt 7min ~ 10min, so that a uniform dark red fluid shape. After removing the crucible in cold water quenching, filled with carefully placed Water 200mL 600mL beaker. Was heated to the reaction, a small amount after the first extrusion frit dilute hydrochloric acid, after the crucible was washed with water, and the washing liquid Into a beaker. The solution boil, place a little clarification, filtered while hot. 20mL1% sodium carbonate solution was washed each three times. On filter paper with HCl 30mL hot 1.1 dissolve the precipitate, the filtrate was collected in a clean 300mL beaker, rinsed with water to a white paper. Add water to About 300mL, added dropwise with stirring on a hot plate heated 5mL1.1 sulfuric acid, cooling, placed more than 4h. 11.3.2 dumping The supernatant was fully transferred to 50mL centrifuge tubes, centrifuged, the supernatant was discarded. With 10mL of nitric acid, 10mL1.1 Wash sulfuric acid, 40mL water followed by precipitation once, discard the eluate. Plus 15mL0.2mol/LEDTA-2Na solution into a centrifuge tube, a water bath Heating, added until the precipitate was dissolved 2mL glacial acetic acid to re-precipitated sulfate precipitation, note the time t1 (228Ac growth starting point). carry on Heating 5min, cooled centrifuge, the supernatant was discarded, the precipitate washed 1 times. Addend drip, placed 2d, so 228Ac and 228Ra reach radioactivity balance. 11.3.3 2d, add 15mL0.17mol/LDTPA solution into a centrifuge tube and stirred, heated on a hot water bath to completely dissolve the precipitate. Sodium sulfate solution was added 2mL1mol L/1mL of glacial acetic acid was added dropwise with stirring, so that re-precipitated, note the time t2 (228Ac decay from point). Heating was continued for 5min, centrifuged after cooling. The supernatant was transferred to 60mL separatory funnel. 10mL precipitate was washed with water once, centrifugal (With 20mL0.2mol/LEDTA-2Na solution to dissolve the precipitate, which can be accessed 5.4.4 into the diffuser exit gas scintillation assay 226Ra). on Serum incorporated into a separating funnel. 11.3.4 to the separating funnel a plus 5mL acid solution, 10mL15% DEHPA- heptane solution, extracted 2min, aqueous phase was discarded. 10mLDTPA with washing liquid to wash the organic phase 1, the aqueous phase was discarded. With 10mL0.5mol/L nitrate back extracted 2min. The aqueous phase was collected In 50mL beaker, the organic phase was discarded. 11.3.5 plus 1mL cerium carrier solution and 2.5mL60% sodium acetate solution into a beaker containing the aqueous phase, with stirring dropping 5mL0.2mol/L Ammonium oxalate solution, low-temperature heating aggregated precipitate. After cooling on a removable filter funnel-like suction system, with a little ethanol washing once, shop After drying the sample in an infrared lamp to just dry. With low background β measuring instrument measuring β radioactivity. Write down the measured time t3 (to the end of the measurement time is 228Ac decay deadline). Then oversight instruments to measure the efficiency of volatility, if necessary, can be corrected in the calculation using 90Sr-90Y balance Supervision sources. 11.4 Determination of the chemical recovery The sample solution is added 133Ba tracer scale fully transferred to 40mL small beaker, diluted with water to the mark. Use containing the same volume Water containing tracer 1mL133Ba same scale small beaker determination of chemical recovery in γ radioactivity measuring device. 11.5 blank test Of the reagents should be measuring reagent of the background. In addition to the sample without ash, the other with the same determination of sample analysis. 12 analysis results presentation 228Ra concentration of radioactivity in food by the formula (4) Calculated. A = NMeλ (t3-t2) 60ERWkb (4) Where. A --- radioactivity in food samples 228Ra concentration in units of becquerels per kilogram (Bq/kg); When N --- net count rate of the sample was measured in units of counts per minute (cpm); M --- fresh ash, in units of grams per kilogram (g/kg); λ --- 228Ac decay constant, the same formula (3); t3-t2 --- sample measurement 228Ac decay time in hours (h); E --- instrument of 228Ac counting efficiency and total self-absorption correction factor, the same formula (3); R --- sample measurement rad......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB 14883.6-2016_English be delivered?Answer: Upon your order, we will start to translate GB 14883.6-2016_English as soon as possible, and keep you informed of the progress. The lead time is typically 1 ~ 3 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB 14883.6-2016_English with my colleagues?Answer: Yes. The purchased PDF of GB 14883.6-2016_English will be deemed to be sold to your employer/organization who actually pays for it, including your colleagues and your employer's intranet.Question 3: Does the price include tax/VAT?Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countriesQuestion 4: Do you accept my currency other than USD?Answer: Yes. If you need your currency to be printed on the invoice, please write an email to Sales@ChineseStandard.net. In 2 working-hours, we will create a special link for you to pay in any currencies. Otherwise, follow the normal steps: Add to Cart -- Checkout -- Select your currency to pay.Question 5: Should I purchase the latest version GB 14883.6-2016?Answer: Yes. Unless special scenarios such as technical constraints or academic study, you should always prioritize to purchase the latest version GB 14883.6-2016 even if the enforcement date is in future. Complying with the latest version means that, by default, it also complies with all the earlier versions, technically. |
