Some standard content:
1CS 67.040
National Standard of the People's Republic of China
GB/T5009.75—2003
Replaces GH/T39—1S8?
Determination of lead in food additives
Determination of lead in food additives2003-08-11Promulgated
Ministry of Health of the People's Republic of China
Administrative Committee of Standardization of the People's Republic of China
Implementation on 2004-01-01
CB/T5009.75—20G3
This standard replaces B/T841!—1967&Determination method 3 in food additives. Compared with GR/8-9—1957, the main changes of this standard are as follows: The standard name has been changed, and the standard name has been changed to "Lead in Food Additives" in accordance with GB/12000.4-2001. This standard is proposed and coordinated by the National Health Commission of the People's Republic of China. This standard was drafted by the Yangzhou Municipal Health and Epidemic Prevention Station of Jiangxi Province. The main contributors to this standard are: Yang Yi, Zhang Liuping. The original standard was issued in 1UX7, and this is the first revision. 550
Part 4: Chemical analysis methods 3 The original standard was used for 1 standardization
Determination of lead in food additivesbzxz.net
This standard is used for the limit test and quantitative test methods of lead in food additives. 2 Principle
GR/T5009.75-2003
The sample is treated with citric acid, pre-ferrous metals and amines to eliminate iron, release ions, and at FH55--9.0, the ions react with dichloromethane to form a red complex, which is extracted with dichloromethane and compared with the standard series for limit test or quantitative test. 3 Reagents
3.1 Nitric acid.
3.2 Acid.
3.3 Chloroform: If it contains lead, use a full-scale instrument to remove it. 3.4 Hydrochloric acid
3.5 Trichloromethane: It should not contain oxides.
3.6 Phenol red indicator: 1g/L acetone, 3.7 Diammonium citrate: 500g/L solution
Weigh 100g of diammonium citrate, add 100mL of water, add 200mL of clear red indicator solution. Hydrogenated water (1+1) to pH 8.59.0. When the yellow turns red, add 20mL of clear), dichloromethane and extract several times. Each time 10mT~20mI.. until the trichloromethane layer does not turn green, and remove the blue layer, then wash twice with monochloromethane, each time 10mL, discard the trichloromethane, and dilute with water to 290 m=
3.8 Hydroxylamine hydrochloride: 21] points/[. box liquid -
Weigh 20 plates of hydroxylamine hydrochloride, add 40ml of water to dissolve, 2 drops of red indicator, add hydrogen 1+1) to adjust the pH to 8.5~9.0: yellow turns red, add 2 drops), dissolve with dihydrogen monoxide several times, each time 10mL~·2Um, until the color of the dihydrogen monoxide layer does not change, add trihydrogen monoxide twice, each time 5, discard the trichloroethane layer, add hydrochloric acid 1+1) to the water layer to make it acidic, add water to 10L3.3 Potassium chloride 100g/L solution,
3.10 Dithiothreitol (dihydrogen monoxide) 0.05% trichloroethane: store in the refrigerator, The following purification method is required: Weigh C.5 ml of the dithiocarbamide, add it to 30 mL of trichloromethane, if there is any residue, filter it into a 253 mL bucket, extract it twice with ammonia water (113), 10 mL each time, filter the extract through a 500 mL filter, adjust the acidity with salt (111), extract the precipitated dithiocarbamide three times with 2 (2,000 mL) trichloromethane, combine them into a dithiocarbamide solution, use a filter to absorb 1.0 mL of the dithiocarbamide solution, add 9 mL of monoxide, mix. Use a 1 cm cup, read the zero point with chloroform, and measure the absorbance at a wavelength of 51 nm.3.11 Standard solution: weigh 3.139% pure lead, add 1 μL 1% nitric acid, transfer to 100ml volumetric flask after solution, dilute with water, this solution is equivalent to 1:1, dilute with water to 1:1 equivalent hand-held lead 3.12: 1ml aldehyde, add to 1:1, GB/T 5009.75—2003 4 %~2% nitric acid condensation bath for more than 2 hours, rinse with distilled water, and finally rinse with deionized water. 4.1 Spectrophotometer:
4.233ml. Liquid separation:
4.325Kjeldahl calcination or 20 calcination
5 Sample treatment
5.1 No test option "Test treatment" can be carried out according to the methods specified in the standard text. 5.2 Organic sample section "Sample treatment" In addition to the provisions of the standard text: - Ship according to the following procedures: 5.2.1 Digestion: Weigh 3. Sample, place in 250ml . Add 1 ml of nitric acid to a flask or conical flask to re-adjust the sample. After standing for a while (overnight), heat until the effect and localization have subsided. Do not add more people. Keep heating until the sensitivity starts to grow. Continue to add nitric acid drop by drop (if necessary, call for nitric acid drop by drop. In the absence of high pressure, pay attention to prevent explosion). Continue heating until the substance is completely decomposed. For example: release a large amount of carbon dioxide. The system will produce white smoke. After recording, the liquid should be completely dry or slightly yellow. , cool the solution to 50ml, weigh it and put it in a bottle, add a little water to the bottle, add the washed solution to the bottle, add the scale, mix well and set aside. 11. When the solution is ready, take 8 test rods: take 5.2.2 of the sulphuric acid and sulphuric acid, and perform the test according to the above method: This method is suitable for samples that are not suitable for natural digestion. Weigh the sample, add a new amount of sulphuric acid to moisten the sample, and then weigh it carefully: Heat carefully until the white is completely simmered, transfer to a temperature-controlled furnace, dissolve completely at 550°C, and take out after cooling. Add 10ml of nitrate (1 + 1), add ash to dissolve, transfer the liquid to a 10ml volumetric flask (if necessary), and weigh the volumetric flask with a little water or washing liquid to the mark, and use it evenly. Analyze the sample every 10 minutes, and make the test by the light-controlled method. 1 limit salt test acid
Pipette the sample and the lead limit mark liquid (lead content must be not less than 125% concentration). Add 1 brand acid to 20).
Add 1m of test solution and lead standard solution. 1 drop of 1m of lemon water (11ml), then add 0mL of potassium fluoride solution. After strong mixing, add F, 0mL. Use only oil to restore the taste, shake vigorously for 1 minute, let the outer layer stand, and then filter the middle layer through cotton into a colorimetric cup. At the return point, measure the absorbance at zero point with methane, or conduct daytime visual production. The absorbance or density of the liquid should not be greater than that of the limit mark liquid. Absorbance color, if the sample is treated, the standard should also be treated in the same way. 6.2 Quantitative determination
Absorb 1) (1.1 or appropriate specific reagent solution, respectively in 125 can of difenoxan, each 1 distilled acid to 20ml.
Standard evaluation solution C.9.0.1.0.3, 0.5.3.71.0ml, (equivalent to C, 1.3.5.7.10 respectively), placed in 13 = mL of separation bucket. Add 1 1 of acid to 2Vm1. Add the sample to the sample, the reagent and lead standard solution to each person's standard solution: ml. Use oxygenated water to reduce the red amine drop. 1+1) until red and then each dose. A2rr1. Mouse deionized water, mix well, each. (: ml. Double-drying, separate green rush 1min, fermentation stomach layer, chloroform after deesterification, often add 1cm colorimetric cup, at the technical length of 15m. Adjust the equal point as needed, formulate absorbance, draw standard curve: 6.3 Calculate the result moss
x - 090
/T5039.75—2003
The amount of lead in the sample, unit is gram per mgg or the mass of the sample solution, unit is microgram (certificate): The amount of lead in the reagent solution, unit is microgram! Try to deduce (volume) unit is gram (or liter g or ml.): The sample treatment volume, unit is liter: The sample obtained during the determination, unit is milligram T), 557
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.