Some standard content:
National Standard of the People's Republic of China
GB/T5009.14——2003
Replacement G3/T5c09.141996
Determination of zinc in foods
Determinatiun of zinc in food2003-08-11PromulgatedwwW.bzxz.Net
Ministry of Health of the People's Republic of China
Standardization Administration of the People's Republic of China
Implementation on 2004-01-01
GB/T5009.14—2003
This standard replaces GR/T5009.14
1935Determination of zinc in food:
This standard has the following differences compared with GB/T5009.14—1996:· The standard has been modified The Chinese name of the standard was changed to Food Determination: It was compiled in accordance with GB7011-201 standard. The chemical analysis method of the original standard was rectified. This standard was issued and managed by the Ministry of Health of the People's Republic of China. The first method was managed by the Health and Epidemic Prevention Station of Yizhou Province and the Health and Epidemic Prevention Station of Guangxi Zhuang Autonomous Region. The second method was managed by the Health and Epidemic Prevention Station of Hunan Province and Tianjin City. The third method was managed by the Health and Epidemic Prevention Station of Guangxi Zhuang Autonomous Region. This standard was first issued in 1985 and revised for the first time in 1996. This is the first revision. 1 Scope Determination of zinc in food This standard is intended for the determination of zinc in food. The limiting value of this standard is: (1.4 mg/kg for absorption method and 2.5 g/g for colorimetric method. 2 Normative references GB/T 5009.14—2003
The clauses in the following documents are the clauses of this standard through the application of this standard. For the referenced documents with the specified date, all the subsequent amendments (excluding the contents of errors) or revisions are not applicable to this standard. However, the parties involved in the technical standard operation can use the latest version of these documents. For any referenced documents without the specified date, the latest version shall be used for this standard. GB/【5CC9:12005 Determination of total organic matter in food - Method 1 - Atomic absorption spectrometry
3 Principle||t After the sample was treated, the original absorption spectrophotometer was used to absorb 3.6% of the original solution. The absorption value was proportional to the value of the standard. It was compared with the standard series for quantification. 4 The chrysanthemum
4.11-methylpentane 2 (MTHK, the name of methyl butyrate) 4.2+23
4.3 (! 11 plate 10 to 120
4.4 mud acid; acid-perfluoric acid (3-), 4.5 zinc injection solution: accurately weigh 0.5Mg gold screen (99.%) and dissolve it in 10ml. Then evaporate it on the water line to nearly, After a small amount of hydrolysis, transfer to a 100mL volumetric medium, dilute with water to the mark, and expand in an ethylene bottle. Each drop of this solution is equivalent to 1.5Umg
4.6 Zinc standard use: Pipette 1U.0mL zinc solution into a 50L permeable bottle, weigh to the mark with hydrochloric acid (0.1mnl/I.), and each milliliter of this solution is equivalent to 1.0mg zinc.
5 Receiver
Original absorption spectrophotometer.
6 Analysis steps
6.1 Sample treatment
6.1.1 Inflammation: Remove the residues and dust in it. Remove the shell when necessary, grind, sieve and mix evenly, take about 5.00g~10.00g of the powder, heat it to a smokeless furnace, and then put it into a 500+25% ashing furnace for 8 hours, then add a little acid after thawing, heat it on a low fire, do not add more acid, repeat the treatment, turn off the charcoal until the powder is cooled, add 11)ml of acid (1+11), dissolve the residue and transfer it to 50)mL of water, then add salt (11+11) repeatedly, add it to the container and dilute it until it becomes light, and set aside. 107
CB/T 5009.14—2003
Collect the same amount of acid and hydrochloric acid (1+11) as the sample, and do a blank test with the same method. 6.1.2 For dyeing, fruits and vegetables; take the edible part first, cut thoroughly, sieve or beat, and freeze 10.00-20.00 ml of auxiliary acid (110), cook over low heat, and proceed as follows. 6.1.3 For eggs, aquatic products and dairy products, take the edible part and filter thoroughly. Weigh 5,008-10.00 ml of water, cook over low heat, and proceed as follows. 1.1 Then move to the furnace..…\ and proceed as follows. Milk is repelled, take 0ml, put it in a porcelain bowl, add 1ml of transferrin (1113). Dry it in a water bath, and char it with a low fire. The following steps are carried out according to the law from 6.1.1. Then move it into a muffle furnace. 6.2 Determination
Take 0.19, 0.30, (.40, 1.83ml. zinc standard solution, put it in a 50ml volumetric bottle respectively, and add salt (1mol)/=) to the scale (each ml is equivalent to 0, 0:24, C8, 1.6). The sample solution, reagent blank and zinc standard solution in each volume are respectively introduced into the flame adjusted to the most flexible temperature for determination. Determination conditions: lamp current 6mA, wavelength 2t3.8nm, peak aperture 3rm. Air flow rate 132./ran.7 Class 2.31./m lamp head height change 3mm, fire background correction T. Use the content to compare the virtual absorbance value, adjust to the standard curve or calculate the linear regression method, compare the test value with the curve or substitute the method to obtain the white content.7 Result calculation
The total sample center current is calculated according to the formula (1X-(AL-A)×X100)
m×1CC
Where:
X—test column average content, unit is gram per gram or gram per liter (/ or mg/L): A
Specimen filter transfer current, unit is gram per milliliter (m/.I.): A:——Zinc content in the reagent air, unit is microgram per milliliter (g/mT)! —Sample mass or volume, unit is gram or milliliter Open (g or mL): the total amount of the treatment, the unit is open (mL) when calculating the result, keep the significant figures.
8 precision
the difference between two independent determination results obtained under the condition of repetitive recording shall not exceed 10% of the arithmetic half mean: second colorimetric method
second method
try to infer that after digestion, at pH 4.0--5.5, the specific ion forms a red complex with disulfide, in tetrachloride fuel. Add chlorinated acid, irradiate, end, chain, silver and antimony plasma, and compare with the standard series, 10 reagents
10.1 sodium acetate solution (/1) weigh 2g sodium aldehyde (11CN.E. water solution 25010.2 ethyl melt (2ir/), take 1 U.0ml. Ice 7. Add Yongwei to 8r.ml. 10.3 Acetic acid-acetic acid needs to be rinsed: ethyl sodium ion filter (2mol/1) and 7. degree (2msl/L) are mixed in equal amounts. The pH of this solution is about 4. Extract the zinc in the carbon tetrachloride layer several times, 1UmI each time, until the carbon tetrachloride layer is green: also remove the carbon tetrachloride layer, and then use a tetrachloride magnetic field to extract the excess acetic acid-aldehyde salt from the dilute carbon tetrachloride package, and discard the tetrachloride precipitate.
10.4 Chlorine water 1+1
10.5 Hydrochloric acid (2ml/) The maximum gel 1 hydrochloric acid water grid dilution rate 10.6 Hydrochloric acid (0.02ml/L), absorb 1ml, salt (2mnl/T.) dilute with water to 100mL, GB/T 5009.14—2003
10.7 Hydrochloric acid hydroxylamine (200/1.). Weigh 20 hydroxylamine, add 60mL water, add hydrogenated water (+:). Measure pH to 4.0-5.5. 11.3 Treat with thiourea-tetrafluoroethylene solution 3.1g/L). 10. Sodium sulfide solution (230/L) is diluted with acetic acid <2mL/L to adjust pH to 0.0-3.5. Next, treat with disulfide-carbon tetrachloride solution 0.1mL/L
10.9 Disulfide tetrachloride suspension [1.1/1.). IC.10 disulfide solution is used overnight, absorb 1.L disulfide tetrachloride solution (0.-/L), add carbon tetrachloride to 1g, CmI. Mix. Use a 12m colorimetric cup and adjust the carbon dioxide to 530m. Read the absorbance (A, 10/1) using formula (2) to calculate the required volume (V) of the dichloromethane solution (57% absorbance). V_1C2-857)_2. 44
-(2)
10.11 Zinc standard solution: weigh 0.1000g of sodium chloride and add 10ml.Salt solution (2 mmol/L): After solution, transfer to 100 mL of water in an equal volume bottle and raise to a peak. This float is equivalent to 1 mL of zinc. 1D.12 Zinc standard solution Collect 1.0 mL of zinc standard solution and place in a 100 mL solution bottle. Dilute to scale with 71 mL of hydrochloric acid (2 mL/L) and water. This solution is equivalent to 1 mL of zinc. 1D.13 Filter with indicator (18 mL/L). Take C. = k red and dissolve with ethanol to 0.1 mL. Use a spectrophotometer. 12 Analytical steps 12.1 Sample digestion GB/T 5009, 1-2CE3 12, 1.
12.2 Determination
Accurately pipette 5ml~1umL of fixed volume digestion ball and the same amount of reagent in a microcentrifuge, place them in a 125mL separatory funnel respectively, add 5ml of water, 1.5mL of hydrochloric acid solution (2C0g/1.), mix well, add 2 drops of cool red indicator solution, adjust to red with nitrogen solution (1-1), add 2 drops more, add 5ml of carbon tetrachloride solution (0.1g/1, then stir for 2 minutes, then transfer the soluble layer to another separatory funnel, extract with a small amount of carbon tetrachloride solution, 2ml~3ml each time, until the green color of carbon tetrachloride filter remains unchanged. The steps are as follows: Combine the extracts, wash with 5L water, take 10L of each time, take 2mL of the extract, take salt (00mL/1), and wash the remaining three residues with carbon tetrachloride. Pipette 0, 1.0, 2.0, 3.5, 4.0, 5.0mL of standard solution (3.1.3, 2.1, 3.2, 4.4.5.9) and put them into 125mL of each separatory tube, add 20mL of acetic acid (0.2mml/1) to each separatory tube, add 10mL of ethyl acetate to each separatory tube and rinse with 1 mL of sodium sulfate ( 2/.1. Then draw a 1.0m2 ball and brush it. After standing and stratifying, remove the cotton and filter it into a four-layer filter. The absorption value at each point of the standard is subtracted from the absorption value of the standard. Draw a standard curve, or calculate the straight line equation. The sample absorption value is compared with the surface line or enter the equation to obtain the effective content. 13 Result calculation
The content of zinc in the sample is calculated according to formula 3. A
mX()×1000
X: The zinc content of a sample, the unit is gram, gram, milligram, ng/kg or mg/(3
CB/T5009. 14—2003
A,—mass of zinc in the test sample digestion, in micrograms (μg); A—mass of zinc in the test blank, in micrograms (μg); V,—total volume of the test sample digestion, in liters (mL); V—volume of the test sample digestion, in milliliters (mL). The result is rounded to two significant figures.
14 Precision
The arithmetic mean of two independent determination results obtained under annealing conditions is calculated: two-colorimetric method [single extraction]
second-color method
15 Principle
Same as in No. 9 Chapter 16 Reagents: 10.3% ethyl acetate. 16.2 Sodium sulfate (25 mL): same as 73%, 16.3 Magnesium disulfide tetraoxide (0.01% MgSO4), 16.4 Magnesium hydroxide (+1%), 16.5 Zinc standard (25 mL): same as 1U.12. Methyl acetate (25 mL): weigh 9.2% methyl acetate (20 mL) and dilute to 100 mL using a spectrophotometer. 18 Analytical procedures: 18.1 Sample digestion: same as 12. :
18.2 Determination
Collect 5L--11ml. of the digestion solution and the same amount of reagent chamber, respectively, and place them in 2mL separatory funnels, add 10ml of water
absorb 0.1.02.5.3.0.4.0,2.0ml standard rapid use (equivalent to 0, 1, 0, 2.0, 5.0, 4.0 (.5.01g for details) and buy them in 12ml respectively. Fill 4, add water to each to 10ml,
Digest the sample, reagent blank and standard sensitizer with hydrogenated water until the sample turns from red to red, rinse with 57%-7% sodium bisulfite (250g/L) and mix well, then add 100ml of disulfide oxidation solution (1/30 mL). Let stand for 4 hours. The following conditions are as follows: 12.2. Calculation of results is the same as in Chapter 13. 20. Precision is the same as in Chapter 14.The determined digestion solution and the same amount of reagent blank were placed in 2mL separatory funnels, 10mL of water was added, and 0.1.0, 2.5.3.0, 4.0, 2.0mL of standard reagents (equivalent to 0, 1.0, 2.0, 5.0, 4.0, 5.01g in detail) were added to 12mL, and water was added to each of the 4 parts to 10mL. Ningge cut [methyl test indicator solution: add hydrogen water until it turns from red to red, then rinse with 57-7.57% disulfide solution (250g/L) and mix well, then add 10.0ml of disulfide oxidation solution (1/3). Then let it stand for 4 hours. The following conditions are as follows: 12.2. 19. Calculation of results is the same as in Chapter 13. 20. Precision is the same as in Chapter 14.The determined digestion solution and the same amount of reagent blank were placed in 2mL separatory funnels, 10mL of water was added, and 0.1.0, 2.5.3.0, 4.0, 2.0mL of standard reagents (equivalent to 0, 1.0, 2.0, 5.0, 4.0, 5.01g in detail) were added to 12mL, and water was added to each of the 4 parts to 10mL. Ningge cut [methyl test indicator solution: add hydrogen water until it turns from red to red, then rinse with 57-7.57% disulfide solution (250g/L) and mix well, then add 10.0ml of disulfide oxidation solution (1/3). Then let it stand for 4 hours. The following conditions are as follows: 12.2. 19. Calculation of results is the same as in Chapter 13. 20. Precision is the same as in Chapter 14.
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