Some standard content:
ICS 67.040
National Standard of the People's Republic of China
GB/T5009.93—2003
/112551995. Generation G13105931
Determination of selenium in foods
Determination of selenium in fonds2003-08-11 Issued
Ministry of Health of the People's Republic of China
National Standardization Administration
2004-01-01 Implementation
CB/T 5009.93--2303
This standard corresponds to A4C:3.102.~8,167s for the determination of selenium in foods (second edition of 1S84), this standard is consistent with A4C3.:02~3, and the quality is not equivalent.
This standard replaces GB/T 1-1996 and GB 13.<5.1991. The determination method of the limit of hydroxylation in food.
This standard is modified as follows compared with GB 14:112393-199: - The determination method in (5:3.051991) is incorporated into this standard. The abbreviation of standard 1264-203.6 is now Part 4: Chemical analysis. The original standard has been comprehensively reviewed. bZxz.net
||This standard is proposed by the Ministry of Industry and Information Technology. The Beijing Municipal Bureau of Health and Medical Products Supervision and Inspection Institute participated in the drafting of the standard. The drafters of this standard are: Yi Guangya, Zhou Ruihua, Gong Huaiji, and Nuclear Light Institute, Ling The original standard was released 105 times, and this revision must be revised. 963
tB/T5009.93-2093
is a micro-element necessary for human movement. Excessive exposure will cause harm to human health. In order to control the amount of human body, the new national standard for the new limit of food in Kunming Industry and Health Machinery/123931996
in food is formulated. In view of the 199s version of the standard The method of combining elements is complicated, and the reagent 2.3-diminuaaplsthairre (also known as DAV) has the following characteristics: completeness. H needs to be imported, so this revision adds a fast, convenient, accurate, and precise method of the atomic ionization method as the second light path method,
1 Standard
Determination of selenium in food
The fifth standard specifies the method of determining the content of selenium in food by the atomic ionization method and/or the method of determining the content of selenium in food. This standard is applicable to the determination of selenium in food products. GB/T5009.93—2003
The first method is 3E. The linear range is 0.01~0.2. The second method is U.5/mI. The sustainability range is ng/L.-403 ng/mJ..
Method 1 Hydride Atomic Fluorescence Spectrometry
2 Principle
After the sample is heated and digested with acid: in a 6ol/1 hydrochloric acid (HCl) medium, the hexavalent source in the sample is reduced to a tetravalent source, and sodium hydride (NaB[[. or potassium hydride (KBET.) is used as a catalyst. The tetravalent hydrogen selenide (S1) is reduced in the hydrochloric acid medium, and the carrier gas is brought into the atomizer for atomization. The ground state atoms are irradiated by a special hollow cathode lamp to quench the high energy state, and in the activated state, a special wavelength of light is emitted, and its light shielding is very strong. Proportional to the same amount of sun: Compared with the standard series: 3 reagents
3.1 sodium iodide (sensitive pure)
3.2 high magnetic grade pure 7.
3.3 hydrochloric acid (grade pure),
3. combination: confirmed warm high Jun certificate! Taiwan age.
3.5 sodium iodide (high grade).
3.G period will be sodium iodide solution (2/[.: weigh .0 turn sodium oxide (NaH, chlorinated hydroxide solution (5g/1.) concave. Then make up to 1000L
37 send mouse sodium iodide (19g:), take 3. iron sodium iodide) mL. The concentration of the product is -g/m4. 4. Atomic photometer 4.2 Electric heating plate 4.3 Automatic temperature control digestion. 5.1.1 Grain: Use the water method as described in the formula twice, dry for 10 minutes, weigh the rust-proof steel, sieve and put it in a new plastic sieve for later use. 5.1.2 Bead dyeing and its physical properties Take a good part of the food and wash it with water. Absorb the water with a cloth: Beat the pulp and set aside. 5.1.3 Weigh or 1, 5x:~, the sample is 5) ml. The sound quotient cup is 10,0 1rT, low aldehyde and [L particle glass chicken beads, the surface of the two 6
GB/T5009.93-2C03
cold digestion overnight: the next day on the electric heating plate heating, and timely add mud aldehyde, when the liquid becomes clear and colorless with a flaky, continue to heat until the volume is about 2m. Do not steam, cool, add 5m6mo./min salt, continue to heat until it becomes clear and colorless with white spots appear, in order to completely reduce the hexavalent coin to the tetravalent coin. Clean. Transfer to a 5CL volumetric bottle, the micro-blank test, 5.1.4 aspirate 10ml of the accurate digestion night dry 1=ml. commercial tube, add 2.1mL of 1mL of 1% ethanol, mix and test. 5.2 Preparation of standard curve
Take 0.5% (1.0, 2.3, 40).5% standard application solution and add 1mL of high ion water into a 15mL centrifuge tube. Then add 2% hydrochloric acid and 1% calcium sulfate. Make a standard curve. 5.3 Preparation
5.3.1 Test conditions: High voltage: 840V, -00m, atomization temperature: 00°C, carrier gas flow rate: 3m, gas velocity: 593m/m: gas velocity 1030mL/min Measurement method: Standard curve method Reading formula Peak identifiable time: 13 Reading time: 1: Liquid time, 3; Sample injection volume: mT.5.3.2 Start of measurement: According to the experimental situation, use one of the following methods: 5.3.2.1 Micro-lubricating formula: Adjust the instrument to the optimal condition. Raise the furnace temperature to the desired temperature, and start measuring after it stabilizes for 10mm-20m.m. Note that the sample is marked in the standard system. After the reading trend stabilizes, switch to the standard system for measurement. Quantity, draw the standard curve: transfer to the test and select the test sample and digestion solution, and clean the sampler before each test. The sample measurement results are normalized and sieved.
5.3.2.2 The instrument needs to calculate the potential force of the result: set the normalization conditions of the receiver, and draw the following parameters in each test: sample mass (or ral.), weigh the concentration of the result (L), and select the concentration of the result. After the temperature of the remote control oven reaches the required humidity, stabilize it for 1umn--20 and then Start measuring, do the zero tube injection of the standard series, wait for the reading to stabilize, switch to the standard series measurement, and make a standard curve. Before switching to the test control, enter the automatic measurement state. Inject the sample into the blank digestion liquid, and let the instrument take the average value as the blank value. Then you can measure the test in turn: After finishing, click "Print Report" to automatically print the measurement results: 5.4 Result calculation
In the formula:
x-(-0>xVxi
×1 G×1 000
X——Selenium content of test sample, expressed as gram per kilogram (mg/kg or n/T). The unit is nanogram per liter (m3/L). C——Selenium content of test sample, expressed as nanogram per liter (ng/mL). V——Total volume of test digestion fluid, expressed as gram (or g/mL). The result shall not be expressed to two decimal places. 6 Density
The absolute difference between two independent determination results shall not be repeated. The second method is fluorescence method
7 Principle
The sample is then digested and oxidized to a dead compound, which reacts with 2-dioxygen (2,3-dihydrogen 2-nitrogen-t, written as DAN) to generate 4.5-nitrogen cyclohexane (4,hIBenzoyiaselcnol). The light emission wavelength is 376, and the light intensity is measured at a temperature of 2m. The net area of the sample is measured:
8 Test
8.! Selenium standard solution
B/I5009.93—2003
Weigh 100 mL of concentrated nitric acid and add 2L of perchloric acid (70-72%) to boiling water. Heat for 3-4 h. After cooling, add 8.4L of hydrochloric acid (hydrochloric acid concentration is 0.1mol/1). Place in boiling water for 2trin. The standard alkali selectivity is -100mL. This is the stock solution (selenium content: 110AR/mT). Cover the stock solution with 0.1mol/L salt solution and store in refrigerator.
8.2LAN(1 L) reagent
This test is carried out in the accompanying car. Collect 21ml of (purity S ~ 0m) acetic acid in a bottle with a lid. Vibrate for about 1 minute and let it all decompose. Add about 40ml of the solution, and then add it into a separatory bucket with technical specifications (cotton wool). After stratification, the cyclohexane has been completely separated. Collect the separated layers and purify them repeatedly with cyclohexane until the fluorescence of cyclohexane is the lowest (about purification times ~ times). Put the purified first [>AV equal to the original layer into a color bottle, add about 1cm of the original layer, until the medium is reduced: if necessary, purify it once with cyclohexane before use: Warning: This test has a certain reproducibility. The personnel using this reagent should have regular laboratory work experience. The user is responsible for taking appropriate safety and health measures and ensuring compliance with relevant national regulations. 3.3% nitrate and 72% nitric acid are mixed with 8.4% selenium and added to 200% water, and then 3% kerosene is added until smoke appears on the sand. At this time, the body should be 230% EDTA mixed with 8.5% EDTA) 21/I.DTA: EDTA disodium 37% water heat rate is fully resolved, the format is as follows Dilute to 5 (m.:h) 1ccg/1. Hydrochloric acid solution: weigh 0.000 ml and dissolve in water, dilute to 1 (ml.c) 0.2g/. Lipstick indicator, except for 5UIg of phenol red, add water (1 + 1:1), after complete solution, add water to 221.
Take the above: > and > and add 6mL of concentrated water. Add 1.86% hydrogen water (hydrogen-water = 1 1).
8.7 Concentrated gasket is relatively small, 18).
8.8 The sample in the broken bowl must be tested for more light impurities first, and the H is checked if necessary. The used cyclohexane can be recycled and reused. 8.910 Acid solution: collect 2ml. Concentrated water needs to be added 0m 9 to collect the fluorescence spectrophotometer,
10 Analysis step
10.! Sample treatment||t 10.1.1 Food
Wash the sample twice with water, and bake in a vacuum oven to remove the surface moisture. Steam it into a stainless steel sample, put it in a plastic bottle, cover it with a lid, and store it for later use.
10..2 Vegetables and plant foods
Take the edible part, wash it once with steamed water, take it out and absorb the water with a cloth, chop it without adding steel, take one piece and bake it in a vacuum oven at 50°C, weigh it, and calculate the weight. Powder it and store it for later use. 653
GB/T5C09.93—2003
Let the sample quality
, 2 test samples of grain or vegetable samples with a digestion rate of about 12.5. Add 1CmE.5% desulphuric acid to the sample. After the sample is moistened, add 25ml of standard solution overnight. Then place it on the sand and gradually heat it: when the sample reacts violently, it will turn into ice color after being heated to white smoke. At this time, the color will gradually turn into ice color, that is, the end point is reached. Some samples will appear cloudy after digestion, so it is difficult to determine the end point. At this time, pay attention to the swelling in the bottle. After cooling, it will turn into fire color. Some samples with higher content need to add 13ml after digestion. 15% benefit, can continue to heat. Make it back to the warning point, to complete the inclusion of - for! , no Si drill fruit will be lower than 10.3 lake set || tt || work described digestion test solution add I into 20mI.EDTA standard wave, with hydrogen water (11) to change hydrochloric acid to red whole kernel II1.5 ~ C, the following class in the room change: Wen DAV test 3 moist about, bone Buddha water bath set heat 5, after receiving the cold mail, add environment 3.Cm, you end a.Move the umbrella part fully into the separator, discard the water layer after stratification, carefully pass the calcined layer from the separator through the test belt, let the water droplets in the environment be drained into the environment, use the excitation light wavelength C1 of 37nm in the fluorescence spectrophotometer to measure the fluorescence intensity of selenium brain, the standard curve of
104 will be able to accurately measure the standard micrograms of 0.0g/m.30.2.1., 2.1 and +.m1. are equivalent to 0.m01.01.Cc5.3.10 and).\, add water to 5\L, and measure according to the formula. When the magnetic content is and in the presence of the following time difference light intensity can be expressed in a quantitative relationship, in the normal preparation of filtered samples, only the reagent space needs to be repeated each time (double the standard part) to calculate the result. The content in the test is in micrograms (μg/m). The standard amount is in grams (m). The calculated result is in grams. The result is expressed in the last two digits of the numerical value. The absolute difference in the result of independent determination of the result obtained in the quantitative reproducibility test is 1% of the arithmetic mean: 86.4
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