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GB 14883.3-2016: National Food Safety Standard -- Determination of radioactive strontium - 89 and strontium - 90 in foods
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National Food Safety Standard -- Determination of radioactive strontium - 89 and strontium - 90 in foods
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GB 14883.3-2016
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| GB 14883.3-1994 | English | 559 |
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Examination of radioactive materials for foods. Determination of strontium-89 and strontium-90
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GB 14883.3-1994
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PDF similar to GB 14883.3-2016
Basic data | Standard ID | GB 14883.3-2016 (GB14883.3-2016) | | Description (Translated English) | National Food Safety Standard -- Determination of radioactive strontium - 89 and strontium - 90 in foods | | Sector / Industry | National Standard | | Classification of Chinese Standard | C53 | | Classification of International Standard | 67.040 | | Word Count Estimation | 18,133 | | Date of Issue | 2016-08-31 | | Date of Implementation | 2017-03-01 | | Older Standard (superseded by this standard) | GB 14883.3-1994 | | Regulation (derived from) | Announcement of the State Administration of Public Health and Family Planning 2016 No.11 |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 14883.3-2016: National Food Safety Standard -- Determination of radioactive strontium - 89 and strontium - 90 in foods
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(Food safety national standard - Determination of radioactive strontium - 89 and strontium - 90 in food)
National Standards of People's Republic of China
National Food Safety Standard
Determination of radioactive substances strontium-89 and strontium-90
Issued on. 2016-08-31
2017-03-01 implementation
People's Republic of China
National Health and Family Planning Commission released
Foreword
This standard replaces GB 14883.3-1994 "Examination of radioactive materials in food strontium-89 and Sr-90 determination."
This standard compared with GB 14883.3-1994, the main changes are as follows.
--- Standard name amended to "national food safety standards in food radioactive material Strontium-89 and Sr-90 determination";
--- The determination of strontium-90 in two - (2-ethylhexyl) phosphoric acid extraction method is adjusted to the first method, the adjustment for the second ion exchange method,
Fuming nitric acid method is adjusted to the third method.
National Food Safety Standard
Determination of radioactive substances strontium-89 and strontium-90
1 Scope
This standard applies to the determination of various foods strontium -89 (89Sr) and strontium -90 (90Sr) of.
Determination of strontium-90 in the first Act II - (2-ethylhexyl) phosphoric acid extraction
Principle 2
Nitrate leaching ash food, di - (2-ethylhexyl) phosphoric acid (abbreviated HDEHP) Extraction of yttrium and other rare earth impurities. After the aqueous phase 14d
Re-extracted with HDEHP generated 90Y, to 6mol/L nitric acid were back extracted yttrium yttrium oxalate precipitation. Measured in the low background β measuring instrument
90Y amount of radioactivity is calculated 90Sr activity concentration. In the affirmative food gray 90Sr-90Y 91Y has reached equilibrium and there is no pollution, can be directly
With the first extract of 90Y via 6mol/L nitric acid was back extracted and after further purification, the same sample preparation 90Y radioactivity measurements, rapid measurement
Given 90Sr activity concentration.
3 Reagents and materials
Unless 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 two - (2-ethylhexyl) phosphoric acid (C16H35O4P). also known as double iso-octyl phosphate, chemically pure.
3.1.2 n-heptane (C7H16).
3.1.3 toluene (C7H8).
3.1.4 Ammonium chloride, trialkylsilyl {[CH3 (CH2) 6 ~ 10CH2] 3CH3NCl}. Acronym N263, before use with an equal volume of 6mol/L nitrate
Solution (if HDEHP- extracted with toluene, then 3mol/L solution of nitric acid) extracted washed once.
3.1.5 sodium hydroxide (NaOH).
3.1.6 sodium carbonate (Na2CO3).
3.1.7 nitric acid (HNO3).
3.1.8 Ammonia (NH3 · H2O).
3.1.9 Hydrogen peroxide (H2O2).
3.1.10 oxalic acid (H2C2O4).
3.1.11 ethanol (C2H6O).
3.1.12 hydrochloric acid (HCl).
3.1.13 insulin (C257H383N65O77S6).
3.2 reagent preparation
3.2.1 sodium hydroxide (NaOH) solution
3.2.1.1 50% solution. Weigh 50.00g sodium hydroxide solution to a little hot water (about 50 ℃, 50mL), cooled to room temperature.
3.2.1.2 6mol/L solution. Weigh 24.00g of sodium hydroxide, diluted with water to 100mL.
3.2.2 Sodium carbonate (as Na2CO3) solution
3.2.2.1 saturated solution. Weigh 45.50g sodium carbonate, dissolved in 100mL of water, cooled to room temperature and boiling capped with a rubber stopper with a test
Bottle for use.
3.2.2.2 1% solution. Weigh 1.00 sodium carbonate, dissolved in an appropriate amount of water, diluted with water to 100mL.
3.2.3 nitric acid (HNO3) solution
3.2.3.1 6mol/L solution. amount of 41.0mL nitric acid, diluted with water to 100mL.
3.2.3.2 3mol/L solution. amount of 21.0mL nitric acid, diluted with water to 100mL.
3.2.3.3 1% solution. 1.5mL amount of nitric acid, diluted with water to 100mL.
3.2.4 hydrochloric acid (HCl) solution of
3.2.4.1 6mol/L solution. amount of 50.0mL hydrochloric acid, diluted with water to 100mL.
3.2.4.2 3mol/L solution. amount of 25.0mL hydrochloric acid, diluted with water to 100mL.
3.2.5 insulin solution. 20 units/mL.
3.2.6 1% collodion solution.
3.3 Standard
90Sr-90Y standard solution. approximately 1 × 103 containing 90Sr decay/(min · mL), strontium, yttrium, each carrier is about 5μg/mL of
0.1mol/L nitric acid (certified reference material).
3.4 Standard Solution
3.4.1 strontium carrier solution (50mgSr2/mL). Weigh 150g strontium chloride (SrCl2 · 2H2O), with 1% nitric acid solution to dissolve, dilute with water
Diluted to 1L.
Calibration. 2.00mL strontium carrier solution is placed in a conical flask, was added 25mL of water, made basic with aqueous ammonia, was added 10mL of saturated carbonate
Ammonium solution, heated to boiling, cooling 30min. The precipitate was filtered to constant weight over No. 4 sand core glass crucible, washed with water, ethanol each
10mL successively washed twice, 105 ℃ drying 0.5h, referred to constant weight.
3.4.2 yttrium carrier solution (10mgY3/mL). Weigh 43.1g of yttrium nitrate [Y (NO3) 3 · 6H2O], was dissolved in 50mL heating
Nitric acid solution 6mol/L in water and diluted to 1L.
Calibration. 2.00mL yttrium conical flask was placed in a carrier, was added 30mL of water and 2mL saturated oxalic acid solution, with ammonia or a 2mol/L
Solution of nitric acid solution pH is adjusted to 1.5, heating condensation and cooling. The yttrium oxalate precipitate is filtered on a removable funnel constant weight of filter paper with
Water, ethanol 10mL each successively washed 2 times, set 45 ℃ ~ 50 ℃ oven dried, referred to constant weight. At this temperature, yttrium oxalate Shen
Starch composition Y2 (C2O4) 3 · 9H2O.
4 instruments and equipment
4.1 Removable funnel.
4.2 low background β meter. The bottom is not more than 3 counts/min.
4.3 Centrifuge. 80mL tube volume above.
4.4 funnel. 250mL.
Step 5 Analysis
5.1 Sampling and pretreatment
Sampling and pretreatment according to the provisions of GB 14883.1.
5.2 Sample preparation and measurement
5.2.1 Weigh 1g ~ 10g (accurate to 0.001g) Food ash in 300mL beaker, the carrier solution was added 2.00mL strontium, yttrium 2.00mL
Carrier solution, adding a small amount of water wetted ash. Added slowly with stirring 50mL6mol/L nitric acid solution and 5mL of hydrogen peroxide, heated to boiling
20min, diluted with water to 100mL.
5.2.2 The food gray of incomplete or excessive residue after 6mol/L solution of nitric acid leaching samples can be transferred to an evaporating dish, add 30mL
Nitric acid, evaporated to dryness on a sand bath, 450 ℃ muffle furnace burning 0.5h, added 50mL6mol/L nitric acid solution and 5mL peroxide after cooling
Hydrogen and heated to boiling 20min, diluted with water to 100mL.
5.2.3 with 50% sodium hydroxide solution to adjust the solution to pH 7-8, was added 30mL of saturated sodium carbonate solution was heated in a boiling water bath for 0.5h
Or so, a few drops of a saturated sodium carbonate solution, the precipitate is completely checked. After cooling, centrifugation, each 30mL10% sodium carbonate solution was washed with Shen
Lake twice. With 6mol/L nitric acid solution to dissolve the precipitate filtered, washed with a small amount of 1% hot nitric acid solution was washed 3 times, the combined filtrate and washings were
Discard the residue.
5.2.4 6mol/L nitric acid solution or 6mol/L sodium hydroxide solution to adjust the pH to 1.0 ± 0.2 (with a precision pH test paper), control
Prepared solution volume of not more than 100mL, transferred to a separatory funnel with same volume of 0.1mol/L balance of 20% HDEHP- nitrate n-heptane solution
Solution (20% HDEHP- or toluene) and extracted 2 times 50mL, shaking 5min. The combined organic phase was discarded and the organic phase or for direct
Determination extracted with 90Y (see 5.2.9). In the aqueous phase was added 2.00mL yttrium carrier solution, placing more than 14d.
5.2.5 pH adjusted solution after standing to 1.0 ± 0.2, with 10% HDEHP- heptane solution (10% HDEHP- or toluene solution) and extracted
Take 2 times 30mL, shaking 5min, separated 90Y recording time. The aqueous phase was retained in the beaker. The combined organic phase was 0.5mol/L
Hydrochloric acid solution (if the solution was extracted with toluene HDEHP-, then with 0.3mol/L hydrochloric acid solution) was washed 2 times 30mL, shake for 2min,
Discard the washing solution.
5.2.6 with 6mol/L solution of nitric acid trans (if using HDEHP- toluene solution was extracted, then 3mol/L solution of nitric acid) and extracted yttrium twice per
Times 30mL, shake for 5min, combined anti extracts. With 20mL n-heptane (or toluene) washing phase 1, shaking 2min, the organic phase was discarded.
5.2.7 After the aqueous phase was added 1.5g of oxalic acid, dissolved by heating with aqueous ammonia to adjust the pH to 1.5, heated to 80 deg.] C, allowed to cool, oxalate
Yttrium precipitate on the inner removable suction funnel filter paper has been constant, with 20mL water, 5mL ethanol precipitate was washed successively, in low background β
Measuring gauge 90Y radioactivity (measurement recording time), followed by measurement of 90Sr-90Y supervision source (5.3.1). After measuring yttrium oxalate precipitate
45 ℃ ~ 50 ℃ dried to constant weight.
5.2.5 5.2.8 The resulting aqueous phase is accurately diluted to 100mL, draw 1.00mL solution, atomic absorption spectrophotometer containing strontium
Volume (Appendix A), calculated strontium chemical recovery.
5.2.9 For determining sample 90Sr and 90Y 91Y has reached equilibrium and the absence of contamination, this law can be simplified, rapid test for 90Sr.
5.2.4 The resulting organic phase was washed with 0.5mol L hydrochloric acid solution/(If the toluene solution was extracted with HDEHP- is 0.5mol L solution of hydrochloric acid/use)
Washed 2 times 50mL, shake for 2min, washing solution was discarded. Press 5.2.6 with 6mol/L (or 3mol/L) nitric acid solution back-extracted
2 times, the organic phase was discarded and the combined aqueous phase. With 50mL20% N263- xylene solution extracted wash 5min, discard the organic phase. The following operation is the same
5.2.7.
Note. When 91Y presence should be placed by law or decay subtraction results were corrected, need to pay attention to 90Y 210Pb-210Bi contamination when using this law.
5.2.10 stable high strontium content of sample analysis if the method is used, when necessary, measure the content of strontium stable food gray. For correction of strontium
Learn recoveries (method see Appendix A).
5.3 supervision standard source calibration source
Preparation 5.3.1 90Sr-90Y supervision Source. Within the inner surface is smooth and clean stainless steel plate measuring a diameter of a circle with the same area of the sample source, are
Even dropped 0.1mL insulin solution, paving dried, and then dropped 90Sr-90Y standard solution, dry paving, then drop 1 drop of 1% collodion solution
Covering the surface of the liquid, dry spare. Source strength of about 2 × 102 decays/min. Using the same standard source plane and the active region the diameter of the sample source
better.
Preparation 5.3.2 90Y reference source
5.3.2.1 Pipette 2.00mL yttrium carrier solution, 2.00mL90Sr-90Y strontium standard solution and 2.00mL carrier solution.
5.3.2.2 2min ~ 5min boiling solution to remove carbon dioxide. Carbon dioxide, ammonia-free solution was adjusted to alkaline, centrifuged, the supernatant was discarded
It was recorded strontium, yttrium separation time.
5.3.2.3 using 2mol/L nitric acid solution to precipitate yttrium hydroxide was dissolved, add a few drops of strontium carrier solution, diluted with water to 30mL, heated moment,
With no carbon dioxide to the acidic aqueous ammonia solution, centrifuged, the supernatant was discarded.
5.3.2.4 with 2mol/L nitric acid solution will yttrium hydroxide precipitate was dissolved, diluted with water to 30mL. 2mL saturated oxalic acid solution was added, with
2mol/L solution of nitric acid or a 6mol/L of ammonium hydroxide solution to adjust the pH to 1.5, heating coagulation precipitation, cooling, precipitate was suction filtered to dismantle
The inner discharge funnel filter paper has been constant, with 10mL of water and 5mL ethanol precipitate was washed successively measured oxalic acid in low background β measuring instrument
Yttrium 90Y radioactivity measurement time record, followed by measurement of 90Sr-90Y reference source. After measuring yttrium oxalate placed in 45 ℃ ~ 50 ℃ dried
He said constant to the same press Y2 (C2O4) 3 · 9H2O chemical composition calculation yttrium recovery.
5.3.3 Calibration with a standard source 90Y 90Sr-90Y supervision Source. prepared 90Y standard source (yttrium oxalate) slightly dry test on a low background β measuring instrument
Amount, and then measuring 90Sr-90Y source supervision, supervision of the source intensity A1 according to formula (1).
A1 =
N1A2
N2
(1)
Where.
A1 --- by 90Y standard source calibration 90Sr-90Y supervision source strength, in units of decay per minute (dpm);
Net count rate when N1 --- 90Y source calibration standard measured oversight source, in units of counts per minute (cpm);
A2 --- standard source added 90Y 90Y radioactivity decay units per minute (dpm);
N2 --- by strontium, yttrium separating net count rate to measure the time interval and yttrium recovery corrected standard source, in units of counts per minute
(Cpm).
6 expression analysis
The concentration of radioactivity in food 90Sr placement method according to the formula (2).
A =
NA1M
60WδRSrRYN3 (1-e-λt) e-λt1
(2)
Where.
A --- foods 90Sr concentration in units of becquerels per kilogram (Bq/kg);
90Y net count rate N --- sample, in units of counts per minute (cpm);
A1 --- by 90Y standard source calibration 90Sr-90Y supervision source strength, in units of decay per minute (dpm);
M --- fresh ash, in units of grams per kilogram (g/kg);
W --- Food Quality ash analysis, in grams (g);
[delta] --- self-absorption coefficient 90Y, 90Y yttrium recovery standard source of the present process is similar sample, approximately 1;
RSr --- strontium chemical recovery;
RY --- yttrium chemical recovery;
N3 --- net count rate when measured sample measurement supervision source, in units of counts per minute (cpm);
--- 90Y decay constant [lambda], in units per hour (h-1); λ = 0.693/T, T is the half-life of 90Y, 64.06h;
t --- first HDEHP extracted after placement strontium, yttrium separate intervals in hours (h);
t1 --- strontium, yttrium isolated measurement time interval, in hours (h).
The concentration of radioactivity in food 90Sr direct method in accordance with the formula (3) Calculated.
A =
NA1M
60WδRYN3e-λt1
(3)
Where.
A --- foods 90Sr concentration in units of becquerels per kilogram (Bq/kg);
90Y net count rate N --- sample, in units of counts per minute (cpm);
A1 --- by 90Y standard source calibration 90Sr-90Y supervision source strength, in units of decay per minute (dpm);
M --- fresh ash, in units of grams per kilogram (g/kg);
W --- Food Quality ash analysis, in grams (g);
[delta] --- self-absorption coefficient 90Y, 90Y yttrium recovery standard source of the present process is similar sample, approximately 1;
RY --- yttrium chemical recovery;
N3 --- net count rate when measured sample measurement supervision source, in units of counts per minute (cpm);
--- 90Y decay constant [lambda], in units per hour (h-1); λ = 0.693/T, T is the half-life of 90Y, 64.06h;
t1 --- strontium, yttrium isolated measurement time interval, in hours (h).
7 Other
Under typical conditions, the detection limit of the method was 1.6 × 10-2Bq/g ash.
Determination of strontium-90 in the second ion exchange method
Principle 8
Nitrate leaching gray food, and the use of citric acid with calcium, calcium, strontium, barium difference ethylenediamine complexing capacity, cation exchange resin column
Separated from each other in EDTA effluent containing strontium, and copper in the form of replacement method makes strontium carbonate precipitate, and then go through the iron hydroxide
After placing 14d pollution. With low background β measuring instrument measuring radioactivity 90Y, calculate the concentration of 90Sr.
9 Reagents and materials
9.1 Reagents
9.1.1 disodium ethylenediaminetetraacetate (C10H14N2Na2O8).
9.1.2 ethylenediaminetetraacetic acid (C10H16N2O8). abbreviated EDTA.
9.1.3 ammonium chloride (NH4Cl).
9.1.4 ammonium acetate (CH3COONH4).
9.1.5 citrate (C6H8O10).
9.1.6 copper chloride (CuCl2 · 2H2O).
9.1.7 phosphoric acid (H3PO4).
9.1.8 Hydrogen peroxide (H2O2).
9.2 reagent preparation
732 9.2.1 styrene strong acid cation exchange resin. 150μm ~ 300μm.
9.2.1.1 resin treatment. a certain amount of strong acid cation exchange resin with a water soaked overnight, rinsed with water to float a resin, dumping
After the solution was soaked with industrial ethanol overnight. 6mol/L hydrochloric acid solution and then soaked in water for 4h, blot it dry with an equal volume of soak 2 times
4h. Finally, washed with water until neutral.
9.2.1.2 packed. Measure 50mL resin (9.2.1), poured into pre-packed at the bottom of a good glass wool exchange column. After loading the reservoir through
Over 200mL20% sodium chloride solution, converted to sodium form of the resin. Then washed once with 100mL, the flow rate of not more than 5mL/min.
9.2.1.3 resin regeneration. with 100mL water to remove EDTA on the resin, and then 200mL20% sodium chloride solution through the exchange of
Column, converted to sodium form resin at a flow rate of not more than 5mL/min. Finally 100mL water to remove excess sodium ion exchange column can be reused
use. To improve the degree of regeneration after exchange column used for several times, may, before the sodium chloride solution by using a solution of hydrochloric acid 200mL6mol L/Shower
Wash, wash with water after hydrochloric acid into the sodium form.
9.2.2 10% EDTA solution. Weigh 100g edetate disodium was dissolved in a solution containing 20g of sodium hydroxide, with
Diluted with water to 1L.
9.2.3 10% citric acid solution. Weigh 10g of citric acid dissolved in 90mL water, prepared before.
9.2.4 buffer solution. Weigh 20g ammonium chloride was dissolved in 500mL water plus 100mL ammonia, diluted to 1L (pH should be 10).
9.2.5 oxalic acid - ammonium oxalate solution. a saturated solution of oxalic acid in a saturated solution of ammonium oxalate solution to pH4.0 ~ 4.5.
9.2.6 Calcium eluent. Weigh 14.6g EDTA and 23.1g of ammonium acetate dissolved in water, diluted to 1L (adjusted with ammonia
to pH 4.9 ± 0.1).
9.2.7 strontium eluent. Weigh 14.9g 23.1g Disodium ethylenediaminetetraacetate and ammonium acetate was dissolved in water, diluted with water to 1L (with glacial acetic acid
PH was adjusted to 5.8 ± 0.1).
9.2.8 3mol/L copper chloride solution. Weigh 51g copper chloride dissolved in water, dilute with water to 100mL.
9.2.9 carbon dioxide-free ammonia. ammonia distillation, distillate was collected, sealed reserve. Fresh ammonia with carbon dioxide-free calcium ions can also check
use.
9.2.10 saturated ammonium carbonate solution. at 20 ℃, take 110g ammonium carbonate, was dissolved in 100mL water, stirred well, the precipitate was filtered off.
9.3 Standard
90Sr-90Y standard solution. Same as 3.3.
9.4 Standard Solution
9.4.1 strontium carrier solution. with 3.4.1.
9.4.2 yttrium carrier solution. with 3.4.2.
9.4.3 siderophore solution (10mgFe3/mL). Weigh 50g of ferric chloride (FeCl2 · 6H2O), was dissolved in 1L0.5mol/L hydrochloric acid solution
Solution.
10 instruments and equipment
10.1 Removable funnel. the same 4.1.
10.2 low background β meter. with 4.2.
10.3 pH meter.
10.4 Ion exchange column. diameter 18mm, height 300mm, as shown in Figure 1 installed.
Figure 1 an ion exchange column
11 analysis steps
11.1 Sampling and pretreatment
Sampling and pretreatment according to the provisions of GB 14883.1.
11.2 Sample preparation and measurement
11.2.1 Weigh 1g ~ 10g (accurate to 0.001g) evaporating dish in the ash sample was added 2.00mL strontium carrier solution, add a small amount of water wet ash, plus
The 30mL6mol/L nitric acid, evaporated to dryness on a sand bath, in a muffle furnace burning about 450 ℃ 0.5h, cooled. Plus 20mL6mol/L salt
Acid solution, boiled for about 5min, then add 20mL boiling water, centrifuged, the supernatant was poured into a 250mL beaker. Plus 20mL6mol/L salt
Acid solution, repeated leaching residue 1 times. Washed twice with 40mL water residue washings combined with the supernatant discarded residue.
11.2.2 added 10mL phosphoric acid in the solution was diluted with water to about 300mL. PH was adjusted with ammonia to 8-9, is heated near boiling, put
Set 1h ~ 2h. Centrifugation, the precipitate washed twice, the supernatant was discarded and the washings (137Cs two solutions were combined for analysis). Minimum precipitation
The amount of 10% citric acid solution was dissolved, was added 2 times 10% citric acid solution EDTA solution volume, mix, diluted with water to dissolve
EDTA solution concentration of 1% hydrochloric acid or sodium hydroxide solution and then the solution was adjusted to pH 4.9 ± 0.1.
11.2.3 The sample solution is well prepared by an ion exchange column, a flow rate of 20mL/min ~ 30mL/min, the effluent was discarded.
11.2.4 eluent with about 350mL of calcium (9.2.6) to give the residual calcium flow rate of 10mL/min. High calcium content of the sample, in order to prevent the leaching of calcium
Wash endless, effluent available oxalate - calcium ammonium oxalate solution then flows through the examination without calcium 50mL eluent. Discard the effluent.
Calcium inspection methods. a test tube of 2mL effluent, with an equal volume of oxalic acid - a mixed oxalate solution, shake 1min. And deionized water phase
Comparison, ...
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