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National Standard of the People's Republic of China
GR/T5009.33—2003
Replaces CBT5009.331396
Determination of nitrite and nitrate in foods2003-08-11Promulgated
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implemented on 2004-01-01
GB/T5009.33-—2003
This standard replaces (B/T5009.35—15S6) Method for determination of nitrite and nitrate in food. The main changes between this standard and (B/T5009.33[SS6] are as follows: The international standard name has been changed, and the Chinese name of the standard has been changed to 3. Determination of the decomposition of the content of the method?
According to G/T2CC9:.1-2001* standard, the original standard has been modified.
This standard is produced by the Ministry of Health of the People's Republic of China, and this standard is recommended by the Food Hygiene Supervision and Inspection Institute of the Ministry of Health, and is funded by the Provincial Health Supervision and Inspection Institute, the Gulin Provincial Health Commission Prevention and Control Station, and the Qingshu Medical College. The standard does not indicate the use of the Chinese postal code. The Standard was first issued in 1998, revised for the second time in 2006, and is the second time approved. 2009-03-2003 Determination of Nitrite and Nitrate in Food This standard specifies the method for the determination of nitrite and nitrate in food. GB/T5009.33-2003 This standard is applicable to the determination of nitrite and nitrate in food. The standard is for ... The detection value is 0.4mg/kg
Hydrochloric acid ethylenediamine method-nitrite determination 2 Principle
After the sample is precipitated with protein and fat removed: under weak killing conditions, nitrite and p-aminosulfonic acid heavy stone are connected with ethyl hydrochloride to obtain a combined red dye: standard comparison: 3 test results: 3.1 Quantity of potassium ferrochlore: Take 10g potassium ferrous chloride (K, FeCN), ·II, and use water to dissolve it to 1ccm3.2 Zinc acetate extraction solution: Weigh 22g0g Zn: +21I. Add 30mL of 7.% water and dilute to 10.L
3.3 Preparation: Take 50g of monosodium glutamate (NB (), 10H0) and dissolve it in 100tm hot water and cool it down. 3.4 Ammonia sulfonate (4/.): Weigh 2.2g of basic acid in 100mT 20% hydrochloric acid and put it in a brown bottle. Preserve it for a long time.
3.5 Hydrochloric acid and ethylenediamine decomposition solution (2g/L): Collect 2.2g of salt and dissolve it in 10Cml water. After mixing, keep it away from light.
3.6 Sodium nitrite standard solution: Accurately weigh 0.10071 ml of sodium nitrite solution that has been dry-burned in a detonator for 21 hours. Dilute with water to 60°C. Each milliliter of this solution is equivalent to 200g of sodium nitrite. 3.7 Sodium nitrite standard solution: Before use, take 3.0mL of sodium nitrite standard solution and place it in a 2TtL container. Add water and adjust to the volume. Dilute with water to 60°C. 4 Instruments
4.1 Small meat grinder,
4.2 Spectrophotometer
5 Analysis steps
5.1 Sample treatment
Weigh 5 μl of the final crushed sample. Add 2.5 mL of saline and mix well. Add 300 mL of about 73% water to wash the sample in 500 mL of volumetric medium. Heat in a deionized water bath for 15 min, cool it to a low temperature, then add potassium ferric oxide while rotating, shake, and then add 5 L of acetic acid to precipitate the protein. Add water to the scale - 300 ml.>h: remove the fat on the surface, filter the solution with a filter, discard the filtrate for 33 min. Filter and set aside. 5.2 Determination Collect 40.0 mL of the above filtrate in 50 ml. Use a colorimetric device 7, and also absorb u.00, 0.20, 0.40, 0.60, 0.80.1.1, =.5012.002.50 ml. of industrial acid standard working solution (equivalent to 0, 1.2, 3.4, 57.5.13, 1.5 sodium nitrite). Measure 26-
GB/T5009.33-2003
51 ml respectively. Use a colorimetric device 100. Add 2 ml of the original standard tube and the test tube respectively. Mix well. After 3 min, add 1 ml of each tube. Add water to the scale. Adjust the absorbance by 1.15 min. Use a 2-nm beaker to adjust the absorbance at a wavelength of 538 nm. Prepare a standard curve for comparison and collect a reagent blank at the same time. 6 Calculation of results The normal content of nitrite in the sample is calculated according to K. Where: The content of nitrite in the sample is The unit is grams per dry gram (g); the mass of the sample is grams (g):
The concentration of the sample used for determination is the effective amount (\g).
The total filtration volume of the sample is in liters (m1.) The sample solution used for determination is in liters (ml.). The calculation results are guaranteed to be valid figures.
The difference between two independent determination results obtained under repeated conditions is given by the arithmetic error of %. Manganese column method - nitrate determination
8 Principle
After the sample is protein precipitated and fat removed, the solution passes through the storage column, and the aldehydes in it are reduced to nitrites. Under weak acidic conditions, the nitrates are diazotized with p-aminosulfonic acid and then combined with saline to form a red dye. The total nitrate content is the total nitrite content, that is, the nitrate content. Reagents: 1. Measure 2.5 ml of hydrochloric acid and add 5.5 ml of cement. Dilute to 10 ml with 1.5 ml of oxygenated water. Mix well. 2. Dilute ammonia level: Take 5 ml of ammonium hydrogen peroxide. Add water to 5a3mT. and mix. 9.3 Salt solution (0.1-100ml/min): Take 5ml of salt solution and dilute to 600ml with 100ml of water. 9. Standard sodium nitrate solution: Weigh 0.1232g of sodium nitrate dissolved in 110-120℃ dry water, transfer to +85ml empty bottle and add 20ml of sodium nitrate to the full scale. 9.5 Standard sodium nitrate solution: When used, add 3ml of sodium nitrate to the standard steel bottle and add water until the density is equivalent to 5.
9.6 Sodium nitrite standard reduction 3.7.
10 Instruments
10.1 Auxiliary columns
10.1.1 Preparation of galvanized steel strips: Add enough zinc or zinc and mix in 50VmL of sodium nitrate solution (2)%/1.>. After 311~4h, when all the cadmium on the surface is completely replaced, use a glass to gently scrape it off, collect the residual cadmium, make it bottom, remove the upper clear layer, wash it with water using constant drainage method, then move it into a tissue crusher, add m., drag about 2, use it to wash the gold particles to the standard culture, and the band distribution is between 2t2
2) and 40 days:
GH/T 5009.33—2003
10.1.2 Loading of cadmium sample: as shown in Figure 1. Fill the tube with water, and use a 2m high hair as a cushion: When the glass wool is pushed back to the bottom of the column, all the air contained in it should be discharged. Gently push the sponge-like pin to a height of -11m. Cover it with high glass. Place a liquid funnel on it. The wooden end should pass through the rubber seat and connect it tightly to the glass tube of the column. If there is no glass as mentioned above, an acid-type full-tube can be used instead. When the pot is filled, wash it with 5ml hydrochloric acid (3.1ml:1), then wash it with water for 2 times, 23ml each time. Seal it with water when not in use, and keep the horizontal surface above the layer. Do not let the pot layer have bubbles 5
more pain, internal classics 35 mr. The outer diameter is mm
, the inner diameter is c.Jn:n, the outer diameter is imm: the outer diameter is 1mnl: the outer diameter is 12mu:, the outer diameter is 1mnl: the outer diameter is 7mm, the outer diameter is 8nu.a, and the outer diameter is 10.1.3. After using the wide single, it should be treated with 251. hydrochloric acid (0. 1/. Select the strips, wash twice with 5 ml water each time. After washing, measure the amplitude with water. 10.1.2 Determination of the overall efficiency of the strips: absorb 2 cm of the standard solution, add 5 ml of nitrogen and rinse with water. After averaging, proceed according to 11.2.2-11.2.3. Take 10 ml of the residual liquid after the strips are washed (10 g of sodium nitrate), and add 10 ml of the colorimetric solution. 5.2 The following technical standards are used to improve the H-component measurement results, and the results are consistent with the training quantity. The reduction efficiency parameter should be 0.1.5% as the requirement. The reduction efficiency should be calculated according to (2). 10
CB/T5QC9.33—2003
Where:
Reduction efficiency:
A——The mass of the measured phase 7. The unit is grams (\B)Ju
The mass of the acid pad used for determination is grams (), 11 Analysis steps
11.1 Sample treatment
1.2 Determination
11.2.1 First rinse the saw with 25mL of hydrogen explosion condensation, and the speed should be controlled at %ml./cx1-5mL/min. The mass transfer tube can be controlled at 2 ntTiin~3 n./nin:
11.2.2 Pipette 24ml of the treated sample solution into 53rt. flask, add ml. of chlorinated sodium sulfate, mix and add to a full flask: separate the sample solution and collect the effluent in the original environment. When the sample effluent in the flask is filtered, add mT to replace the sample solution in the flask. 11.2.3 All the collected solution is filtered through the flask as before. The second effluent is collected in a 90ml container and then washed with water for three times, 2ml each time. Collect all the effluent in a dissolving bottle, add water to the solution until it is thick, mix and add 10ml.~20ml. of the original sample solution into a 51ml colorimetric tube and add 5.2% ethanol to 0.0C.0.20. 0.40.0.60.0.8c.1.00..\ and then proceed in accordance with the law. 11.2.5 Determination of nitrates Pipette 40ml of the sample solution in 11.1 into a 50ml colorimetric tube. Calculate the content of nitrates in the sample according to formula (3) according to 5.2\pipette 004081. and then proceed in accordance with the law. 12. Calculate the content of nitrates in the sample according to formula (3) 4,2000
support towel;
the content of salt in a sample, in milligrams per kilogram (mg/kg); r
the appropriate amount of the sample, in grams ()
the mass of sodium nitrate measured after cell reduction is in grams (), 4:- the mass of nitrates provided by the technical measurement: the individual is minute (B); :.232
The coefficient for converting sodium nitrate into nitric acid: The total volume of the sample treated for total sodium nitrate, in milliliters (ml); The total volume of the sample after reduction, in milliliters (ml); The total volume of the sample after reduction, in litres (l); The total volume of the sample treated for direct nitrite, in nml.)! The sample solution obtained from the sample treatment with sodium nitrate, in litres (l). The calculation result is rounded to the nearest significant figure:
13 Precision
The absolute difference between two determination results under single-phase conditions is greater than 10% of the arithmetic mean, 254
...(3)
14 Principle
Oscillographic polarography - determination of nitrite
GB/T 5009.332003
After precipitation and fat removal, the ester salt is oxidized with pyrrolidone sulfonic acid under radioactive conditions, and then reacted with 8-base dye under weak alkaline conditions. The dye is reduced to produce cyanide. The concentration of cyanide and cyanide is linear, which can be compared with standard silicon. 15 Reagents
15.1 Potassium cyanide solution, 0.50% potassium cyanide LKF (CN). · 3H, decompose with water, and release to 1900ml..
15.2 Acetic acid solution: weigh 22U.g acetic acid LZn)) · 2JIO. Add) ml. ice 2000 to dissolve wood. Mix until: 000 ml.
15.3 Evenly mix the slurry, take 5.Cg sodium phosphate (NaB2O3, (1g/L), dissolve in 132ml. hot water, reserve for later use. 15.4 Hydrogen-based extract solution (8/): weigh 2g amino acid sulfonate, dissolve with hot water, add 25mL hydrochloric acid 1.ml/: transfer to 2 volumetric flask and dilute to the mark.
15.53-Based phenoxylate solution (1g/T.): weigh 0,250R8 bacteria, add 1ml. salt fermentation ((1-1el/1.) and a little water to dissolve and transfer to 2=CI through the flask to dilute the whole system.
15.6EIITA solution (10ml/L), take 3.722H1)TAHN,OAa2H, 0.3CmL water solution and transfer to 1C.C.ml. volumetric flask and dilute to the mark. 15.7 Water (5:100 mT) absorbs 28% sodium nitrite in a volumetric flask and adds 0.1000 mg of sodium nitrite to the mark. 15. Dissolve the sodium nitrite in a volumetric cup: accurately weigh 0.1000 mg of 24% sodium nitrite, add hydrolyzate into a 5 mL volumetric volume and add to the mark. This value is equivalent to 200 mg of sodium nitrite per mL. 15.9 Nitrous acid: accurately absorb 5.0 mT of sodium nitrite or sodium nitrite in a 20 mL volumetric volume and add water to the mark. This value is equivalent to 200 mg of sodium nitrite per mL. 54g of nitrite. Take 13.32ml of the solution. Put it into a volumetric flask and dilute it with water until the solution is 100ml. 16. Collectors of nitrite beer
*6.1 Small meat extractor.
16.2 Detailed instrument.
17 Analytical steps
17.1 Sample treatment
Take 5.000ml of the sample (mixed with a grout, temperature: 0.20-20.32), and dilute it to 50m 2. Saturated sand was stirred evenly, washed with 300% water, heated in full water for min. The mixture was cooled to room temperature, then rotated, and 10 ml of ferrous acid solution was added. Then 5 ml of zinc sulfate solution was added to resist the protein reaction. The mixture was fully hydrated and allowed to stand for 0.3 hours. When the second layer of fat was removed, the first filter was filtered through energy paper, and 50 L of the product was discarded. The melt was filtered through a filter with a density of 17.2 ml and a filter was collected for 3 hours. Volumetric flask (or colorimetric medium), take 0.0, 50, 1.00, 2.2.3), 5.00ml. sodium aldehyde standard solution (cabinet and ten 0.0.2.0.50.3.75, 1.00.1.2=, 1.53g sodium arsenate) in 1cml volumetric flask: or colorimetric standard and sample were added mA drop (010m.) 1ml paraformaldehyde pot acid drop (3/mud, static for 4min each into 1.8-difference sphere drop concentration (1g and.m=hydrogen 265
GB/T 5009.33—20C3
water: 5%), dilute with this to mark the scale, mix well and let stand for 13min~1:min, transfer the whole formula into the rate cell (10n small Rao Huai!) and measure on the capacitance electrode instrument using the standard system (the working electrode is the operating electrode, the electrode materials are the same as those of the chemical and water: platinum is the auxiliary electrode)
17.3 Determination reference conditions
The origin potential is adjusted to -0 .2
Estimated single is 3.」! You can choose the appropriate magnification according to the amount of salt in the sample. If the content is high, the magnification is high. The rate is selected at 0.1 or higher. If the magnification is selected at 1 or higher, the switch of the plate is switched to the first electrode and the lead-in gear is turned on.
Measurement cycle: Put a core barrel into the electrolytic cell with a relatively large
, and each time the instrument scans automatically, it reaches, and records a peak value of 0.V (allowable median fluctuation: 0 mV20mV) on the screen, and draws the standard curve to compare the results.
Try to infer the content of neutral nitric acid according to formula (4) to calculate it, 4×1cus
x(V/V):[00×1 000
x-the content of neutral salt in the sample, in grams (g/): the mass of nitrite in the test wave, in grams ()! 1. The total volume of the sample solution is mL); the root of the determination is liter (m[.); the mass of the sample is in grams (:
The calculation result retains two decimal places,
19 precision plate
Under the condition of annual quantitative analysis, the absolute value of the two independent determination results shall not exceed 1 length of the average value of the technical method, 26
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