Some standard content:
ICS67.040
National Standard of the People's Republic of China
GB/T5009.18—2003
Recommended GB/15503.18-1Ss6
Determination of fluorine in food
fokds2003-08-11 Issued
Ministry of Health of the People's Republic of China
Standardization Administration of China
2004-01-01 Implementation
GB/T5009.18-2003
This standard replaces 3/5C9.8-199 Food Standardization Method This standard and G/TEC69H1396 are revised. The Chinese name of the standard is adopted as the supplementary name of the standard. 3: According to the 1T0001.4-1 standard writing plan, the fourth part: chemical analysis method, the original standard structure is revised!
This standard is issued and registered by the People's Republic of China. The first standard is the Institute of Food Safety and the Ministry of Industry and Information Technology. The second standard is the first edition of this standard in 1985 and the first edition in 1935. This is the second revision. 124
1 Scope
Determination of fluoride in food
CB/T5009.18—2003
This standard specifies the determination of fluoride in grains, vegetables, beans and their products, meat, blood, and small foods: This standard is suitable for the determination of fluoride in foods, but it is not suitable for samples with high fat content such as beef, etc. that have not been calcined.
Method detection limit: Method 1 is .mk Method 2 is 1.25%/k Method 1 Diffusion-fluorine reagent colorimetric method
2 Principle
The fluoride in food reacts with acid in the diffuser to produce a certain amount of gas, which is absorbed by sodium hydrogen ion through diffusion effect, and forms a blue binary complex with the increase of ion desire. The color deepens with the increase of ion desire, and is extracted with or without a commercially available solvent. Compared with the standard series, the water used in this recipe does not contain the largest ion, and the reagent is about 3. 1 propylamine.
3.2 silver sulfate-sulfur glue braid <227.1 weigh? sulfuric acid, put in 100ml. sulfuric acid (3-1, 3.3 hydrogen ions-anhydrous ethanol solution (take 1 room temperature oxidation: stop and dilute to m. 3.47 midnight (1mol/L: report 3mL ice 7.5 stop oxygen mixture, water to = 0ml.3.5 stop oxygen mixture, etc., add a little water and 14U more than the oxidation of sodium acetate: 135x sodium acetate (5> H (red envelope), add water to sieve to 533mT and then keep in the refrigerator 3.6 Sodium acetate (25) g/L.
3.7 Dissolve: Collect 22 ml of sodium acetate. Dissolve, add water to 15 °C ml. Use acetic acid (25ug/L) to adjust pH to 5.U. Then dilute with water to 5% PH, and store in refrigerator. 3. Take 3 acetic acid-free solution 110 ml of water and add 22 ml of glacial acetic acid to adjust pH to 4.7. Then dilute with water. 3. Take 110 ml of diethyl aniline solution, take 2 hm1 of amine and add 500 ml of alcohol. 3.10 chlorinated acid (1 u g 2)
3.11≤ Chemical drop liquid (10g/ml) Take 4 sodium oxide and boil it in water until it reaches 10m.T.3.12 Standard drop liquid: weigh 0.221g of sodium oxide that has been cooled for 35-105 hours, gradually transfer it into 1CCral. Add water, add a little water, and store it in the water. This drop liquid is equivalent to 3.13 Standard oxygen concentration; absorb 1.11r:1 oxygen solution, put it in a ml. weigh bottle, add water to the scale, use a paper spoon, and this liquid is 5.
3.14 Filter Paper: Put the paper into *4.5 injection of sodium hydroxide (40g: 1) 100g water alcohol ratio, 100g 2 T strips 2 instruments
2.1 Plastic bulk box: diameter 1.3m deep 2, cover Chuanjian smooth, non-with \ raised (need to wave hydrogenation absorption) cover the whole dissatisfaction. Other award-type transfer boxes can also be extended to j1:s
GB/5009.18-2003
4,2 Hengmeng box: 553 on 1.
4.3 Spectrophotometer.
4. 4 Aldehyde meter.
4.5 With furnace.
5 Analysis step
5. 1 Diffusion monochromatic method
5.1.1 Sample treatment
5.1.1.1: Cereal sample, after beating, other visible materials are removed, take 5CB~10R powder from representative test pen: sieve for 1 day,
5.1.1.2 Take F part of the parent, clean, cool, machine, mud, take 1008~200 2 wind, crush, sieve for 40 days. When the results are expressed before, the water content should be added: 5.1.1.3 Special test column (high fat content, small easy to crush test mix, such as peanuts, fertilizer, high content of fruit, etc.): weigh 1.g~2.00g of the test waste (silver, porcelain, etc.), add 4ml of chlorinated acid (100/L) and sodium hydroxide (1CG/1.) to make a certain reduction, mix well, and then pass through a pool for 5.5 to fix the chlorine in the test column, then evaporate it in a water bath, heat it until it does not smoke, and then ash it in a 63° furnace for 4 hours to get complete ash, take it out and cool it to take the ash for diffusion. 5.1.2 Determination
5.1.2.1 Take the whole box! Put the box in the center of Jinyi, such as 3.2 yuan, sodium-Taiben 7 alcohol solution 40g/L), store it in the city, and average it at 35°C! Bake in a constant temperature box to form a layer of smelting quickly, take out the mountain preparation month, or batch paper! (3.14) Paste" inside, 5.1.2.2 weigh item i. 7. The treated sample is placed in a material box, such as 4mL water, so that the test is evenly distributed and the storage is not enough. Product 1YT. Silver-acid-building acid device (23S/1.), immediately add the end, gently probe the spoon: if the sample is measured after ashing, then transfer all the ash into the whole box, fill it with 15% water and it is still clean: pour the washing liquid into the single material point, and make it evenly distributed: if the sample is not completely cleaned, add 4m condensed lactic acid solution (20/10) and other liquids to continue the washing liquid into the plastic, cover it and gently probe the spoon head at 55: ±1℃ constant temperature for 20h
5.1.2.3 Add, U.2,., 0.8, 1.2.=.6m1 oxygen standard single (machine 9, =.0.2.0, 4.0.6.0, .1g multiplication) into the material box respectively: make up to 1ml, each (21g. 4ml of aldehyde-sulphuric acid was immediately squeezed, and the sample was cut into pieces and squeezed into the micro-pipette for 20 minutes. 5.1.2.4 Take out the box, remove the box cover, and use 2mL of the original in batches. Before the plate is oxidized to full film rate, use a dropper to carefully transfer it into the separation funnel. 5.1.2.5 Add 3mL of 3.0L of chelating solution of 13.0mL of water to the separation funnel, mix, and let stand for 2 minutes. Add 1g.\)ml of ethylamine-isopropyl alcohol 5+10mL solution, shake for 2 hours, and wait for the pieces to be separated. Discard the water and separate the pieces. Use source paper to inject energy into 0mL dense colorimetric tube 5.1.2.E month 1cm colorimetric cup! 53nm lock length with the standard kidney to adjust the zero point, measure the absorbance value of the system into a line, or sample light and mountain line to compare to obtain the mouse.
5.1.3 Result calculation
The actual content of the sample is calculated according to formula (1), AX1600
m X 10
Where:
x-: The content of the test particle at the center, the unit is mg per gramAnalyze U.5ml. Add the solid solution (152g/.) to the solution, and then add C.5 water for three times. Carbonize at low temperature until the remaining smoke is less than 1 day. Transfer to the oven, heat at 500℃ for 6 hours, and let it cool. 9.3 Steaming
9.3.1 Add 1L of water to the vortex, add a few drops of ether (2:1) to make it diffuse, prevent the rate of ether from flying, and make sure that there is no bubble. s
GB/T5009.18-2CO3
is correct. Transfer this condensate into 509)ml. According to the tumor medium. Use 2Gml. This fraction is divided into several times and is detailed. Put it into the process bottle, 9.3.2 Dry steam who adds 6TL sulfuric acid (2 twelve) to the bottle to steam the filling without any regeneration, and heat the steamer. The effluent was collected in a 50mL beaker with 5ml of water, and then dripped into the 50mL beaker with phenol indicator solution (1mL/min) until the temperature in the beaker reaches 10℃ (the time for the effluent is about 15min~2min). 9.3.3 Remove the residual tube, stain the tube with disinfectant water 3 times, rinse with water and transfer the collected solution into the beaker: transfer the collected solution into a 51mL volumetric flask, rinse the beaker with a small amount of water, and add the solution to the beaker. Add 1mL (10mL) until the red color disappears. Dilute with water to a concentration of 1:1, and filter. 9.3.4 Collect 0, 1.0, 3.0, 5.2, 7, 0.9.0tL of standard effluent or ten distilled water respectively. Add ≤30ml of this. The following is changed according to 9.3.2 and 9.3. This sieve standard wave is divided into 0, 1, 3.0, 0, 3.0, 9.4 fixed
9.4.1 Pipette 2.0ml of standard series standard policy and detailed distilled liquid respectively. Put it into the tube with stopper ratio. 9, 4. 7 net, 2. 2. Operation
9.4.3 Calculation of monochlorinated oxygen content: AXVX1000
X. The content of monochlorinated chlorine in the sample, in whole gram per kg (rue/kg); A: The mass of oxygen in the sample solution for determination, in micrograms (micrograms); V: The volume increased by heat absorbed during colorimetry, in nanometers (nm); The total volume of benzene solution, in millimeters (mM);
--The mass of the sample, in grams (g).
The expression of the end: Same as 5.1.5.
9.4.4 Width of the end: Same as 5.1.4
Method 3 Ion Selective Electrode Method www.bzxz.net
10 Summary
The selective oxidation of the membrane oxygen ion produces a logarithmic response of the electrode and the saturated electrolyte. The potential difference changes with the change of the electron activity in the test liquid. The potential change dynamic impulse conforms to the energy characteristic (e) strong formula. Bayesian formula (3).
FE 2. ug RT gC-
5F is a linear relationship. 0F is the material rate of the line. 5.1G can be fluorinated to form a complex of iron, aluminum and other ions "T interference, other normal ions have no effect: the measured acidity is pi1S--6. The ionizer eliminates the influence of ten ions and the degree of 11 reagents
This method does not contain deionized water, the test materials are analytically pure, all test materials, cumulative ethylene plastic tax. I1Z yana drop was weighed 4 ethyl (OH) drop 00m water, Z acid (1 H 7. Water selection rate
11.2 g sodium citrate drop (0. 7: m.nl/l:: weigh 11m sodium thiazoline acid? Nz: L, [1.0). 2JI, () ) dissolved in 300 m water, add [4ml. peroxy acid, add water to dilute to 500ml. 11.3 Total ionic strength line: 7. Transfer liquid: 3 [0.: L) and the image late sodium solution (0.75m = 1/1. equal amount of wet, when the pressure appears 119
GB/T 50C9.18-2003
11.4 Pan acid (1) same, 2,
11.5 Bottle standard signature: same 3.13
11.6 Oxygen standard working liquid: aspirate 10.0mI. annual standard permeate solution into 100ml, permeate solution, such as water dilution to the scale, so that each liter of the foil solution is equivalent to 1.0 oxygen. 12 only egg
12, 1 telegram.
12.2 Acidity meter: 19.01 pH value (calculated). 12.3 Magnetic stirrer,
12.4 Electrolyte.
13 Analytical steps
13.1 Weigh 1.00 g of the sample crushed through a 40-day sieve and put it into a 50-liter volumetric flask. If the amount is slow (10 mL), pipette for 1 hour with occasional gentle lifting. Try to avoid the sample sticking to the instrument. 25 minutes after extraction, rinse with water until the sample is moist, take 0, 1.0, 2.0, 5.0, 10.2 ml of standard oxygen solution (equivalent to 1, 1.0, 2.0, 10.0), and discard them, and add 1 mE of each sample slowly, 10 m (11:), add water to the scale, and connect the negative end of the sample electrode and the stopper with the hook. Insert the 2:1 plastic rod filled with water, put the sample in the cup, read the level, replace the water piece 2~3 times, and after the potential is balanced, measure the potential of the sample solution and the standard solution. 13.4 With the neutral potential as the ordinate and the fluorine quotient as the abscissa, a standard curve is prepared on a semi-logarithmic scale, and the content is obtained on the curve based on the test potential value.
13.5 Conclusion Calculation: The content of the sample is calculated according to formula (4). AXVX1OCC
wX」Uuo
The standard content of the sample is milligrams per gram (mg/ks). The concentration of fluorine in the sample solution for determination is micrograms per milliliter (/ml). A
The amount of sample, in grams (g):
The total amount, in milliliters (mL).
The calculated result shall be rounded to a valid figure.
13.6 Precision: The absolute difference between two independent results obtained under the condition of accuracy shall not exceed 20% of the actual mean value.
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