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GB 31643-2016: National Food Safety Standard -- Determination of Irradiated Foods Containing Silicate -- Thermoluminescence Method
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| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Standard Title (Description) | Status | PDF |
| GB 31643-2016 | English | 109 |
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National Food Safety Standard -- Determination of Irradiated Foods Containing Silicate -- Thermoluminescence Method
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GB 31643-2016
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Basic data
| Standard ID | GB 31643-2016 (GB31643-2016) |
| Description (Translated English) | National Food Safety Standard -- Determination of Irradiated Foods Containing Silicate -- Thermoluminescence Method |
| Sector / Industry | National Standard |
| Classification of Chinese Standard | C53 |
| Word Count Estimation | 5,599 |
| Date of Issue | 2016-12-23 |
| Date of Implementation | 2017-06-23 |
| Older Standard (superseded by this standard) | NY/T 1207-2006; NY/T 1390-2007 |
| Regulation (derived from) | National Health and Family Planning Commission Notice No.17 of 2016 |
| Issuing agency(ies) | National Health and Family Planning Commission of the People's Republic of China, State Food and Drug Administration |
GB 31643-2016: National Food Safety Standard -- Determination of Irradiated Foods Containing Silicate -- Thermoluminescence Method
---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.
TL (Thermoluminescence). silicate mineral when heated, the original radiation energy is absorbed in the crystal lattice traps
Released in the form of photons phenomenon.
Principle 3
Adhesion of the silicate mineral in the surface of the food in an ionizing radiation, the radiation energy can be stored by the charge trapping embodiment. These ones
After being separated silicates placed a certain temperature environment, the stored energy is released as light, this phenomenon is called thermoluminescence.
Measure and record the thermoluminescence signal forming thermoluminescence curve.
Thermoluminescence intensity available thermoluminescence curve area value represented. Different types and quantities of silicate minerals, generated TL
Signal is also different. In order to eliminate the difference silicate species, the samples need to be measured twice thermoluminescence light. G1 indicates that the sample to silicate
A thermoluminescence glow curve area value; samples after administration of the dose of radiation is determined, the sample TL measured again, and the table with G2
Area values shown secondary emission curve, with final decision G1/G2 value of the sample was irradiated or not.
4 Reagents and materials
Unless otherwise indicated, the reagents used in this method are analytically pure water three water GB/T 6682 provisions.
4.1 Reagent
4.1.1 hydrochloric acid (HCl).
4.1.2 hydrogen peroxide (H2O2).
4.1.3 acetone [(CH3) 2CO].
4.1.4 Multi-sodium tungstate (3Na2WO4 · 9WO3 · H2O).
4.2 Reagent preparation
4.2.1 1mol/L hydrochloric acid solution. 90mL amount of hydrochloric acid and diluted with water to 1000mL.
4.2.2 1.7g/mL plurality sodium tungstate solution. Weigh 700g plurality sodium tungstate dissolved in an appropriate amount of water, and dilute to 1000mL.
5. Apparatus
5.1 thermoluminescence dosimeter. Measuring range. 0.1Gy ~ 10kGy; linear heating rate. 1 ℃/s ~ 40 ℃/s.
5.2 ultrasonic oscillator.
5.3 low-speed centrifuge. speed ≥1000r/min.
5.4 Ovens.
5.5 Electronic balance. a sense of the amount of 0.1mg.
5.6 ionizing radiation. use of ionizing radiation sources and management should GB 17568 and GB/T 25306 requirements.
Step 6 Analysis
Sample preparation before 6.1
6.1.1 spices and dehydrated vegetables
Samples were weighed 100g, placed in a beaker, adding a sufficient amount of water immersion, mixing was allowed to stand. Ultrasonic treatment 5min, filtered with a suitable filter
(Such samples may be used Rough 250μm aperture sieve) and the filtrate was collected in a beaker and deionized water into the filter cake on the filter for
Flushing line, the flushing fluid collected in a beaker and allowed to stand. Remove the upper solution, the bottom of the beaker reserved minerals (organic if not once cleared,
Multiple samples may be soaked in water, and then the excess solution is removed). The mineral was transferred to a centrifuge tube, 1000r/min centrifugal 1min, to
In addition to excess water, mineral deposits retained bottom of the tube.
6.1.2 fresh fruit and vegetables
Weigh the sample (and Eggplant fruit, root vegetables skin samples were taken, the thickness of not more than 5mm; leafy vegetables outer leaf samples were taken
Sheet) 500g ~ 1000g, placed in a beaker, adding a sufficient amount of deionized water immersion. Ultrasonic treatment 30min ~ 60min, left to settle 4h,
Removing the upper layer solution (the solution was filtered using a suitable filter, if necessary). The precipitated bottom of the cup into a centrifuge tube, 1000r/min centrifugal
10min, to remove excess water, mineral deposits retained bottom of the tube.
6.2 Mineral extraction
Centrifuge tube containing minerals was added 1.7g/mL solution of sodium tungstate plurality 5mL, vigorous shaking, sonication 5min ~
15min. 1000r/min centrifugal 2min, minerals precipitate. An appropriate amount of deionized water added to cover the upper layer of sodium polytungstate solution, and then the
The aqueous layer was removed (this step can be repeated operations until clean and remove organic matter). Sodium polytungstate solution carefully removed tube, the end of the tube retained
Minerals. Adding a sufficient amount of deionized water and twice with minerals, low-speed centrifugation or standing mineral deposits, to remove excess moisture.
Was added 1mol/L hydrochloric acid solution 1mL ~ 2mL, mixed, allowed to stand 10min. In accordance with the hydrogen peroxide solution volume ratio of hydrochloric acid
Relationship 2.1 amount of hydrogen peroxide was added, mixed and the reaction was allowed to stand 12h. Removing the upper layer solution was washed twice with water, allowed to stand, to remove excess water
Minute. Adding an appropriate amount of acetone, the samples were transferred to a clean mineral sample pan and placed in drying oven temperature 50 deg.] C.
6.3 thermoluminescence spectrometer reference condition
a) heating rate. 6 ℃/s;
b) Heating temperature range. 35 ℃ ~ 500 ℃;
c) preheating temperature. 50 ℃;
d) thermoluminescence glow curve area integral temperature range. 100 ℃ ~ 500 ℃.
6.4 Determination of Sample
6.4.1 G1 measurement
6.2 weighed precipitate was collected to test 0.1mg ~ 1mg, thermoluminescence evenly into the spectrometer to measure small disk, by 6.3 a) ~ c) Regulation
Given measurement conditions, recording luminescence curve, the curve is calculated by the integral value of the light emitting area 6.3 d) condition value, he expressed in G1.
6.4.2 G2 Measurement
6.4.1 placed with the treated samples and measuring the dark box tray, ionizing radiation administered particular dose irradiation (spices and
The reference dose dehydrated vegetables products as 1.0kGy, the reference dose of fresh fruit and vegetable products as 0.5kGy). By 6.3
Condition a) ~ c) a second predetermined measure, record emission curve, the curve is calculated by the integral value of the light emitting area 6.3 d) values of the condition to
G2 represents.
NOTE. To ensure accuracy of the measurement signal TL, TL spectrometer should be regularly corrected, to ensure stable background reading instrument. Conditional
Then heating the sample chamber should be cleaned with liquid nitrogen prior to each measurement.
7 expression analysis results
7.1 calculation results
Integrated area ratio according to equation (1).
f = G1/G2 (1)
Where.
f --- the ratio of integrated area;
Gl --- luminescence curve area value of the first measurement;
Emitting area value G2 --- second measurement curve.
Results retention to two decimal places.
7.2 results found
7.2.1 spices and dehydrated vegetables
If f≥0.10, irradiated sample is judged to have been processed.
If f < 0.10, it is determined that the sample is not irradiated through the process.
7.2.2 fresh fruit and vegetables
If f≥0.10, irradiated sample is judged to have been processed.
If f < 0.07, it is determined that the sample is not irradiated through the process.
If 0.07≤f < 0.10, it is not determined whether the sample through the irradiation treatment.
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