Some standard content:
Chemical Industry Standard of the People's Republic of China
Food Additives
4-Chlorophenoxyacetic Acid Sodium
Subject Content and Scope of Application
HG 2302-92
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation and storage requirements of 4-chlorophenoxyacetic acid sodium. This standard applies to 4-chlorophenoxyacetic acid sodium made by condensation and refining of p-chlorophenol and chloroacetic acid under alkaline conditions. This product is used to cultivate rootless bean sprouts.
Molecular formula: CHO, CINa
Structural formula:
CH, COONa
Relative molecular mass: 208.6 (according to the international relative atomic mass in 1989) 2 Reference standards
Chemical reagents
Preparation of standard solutions for titration analysis (volume analysis) GB601
Chemical reagents
Chemical reagents
GB 617
Chemical reagents
GB1250
GB8450
GB8451
3 Technical requirements
Preparation of standard solutions for impurity determination
Preparation of preparations and products used in the test method Melting point determination method
Expression and determination method of limit values Determination method of arsenic in food additives
Test method for heavy metal limits in food additives 3.1 Appearance: white needle-shaped or prismatic crystals. 3.2 Food additive sodium 4-chlorophenoxyacetate should meet the requirements of the following table. Approved by the Ministry of Chemical Industry of the People's Republic of China on June 1, 1992 and implemented on January 1, 1993
Sodium 4-chlorophenoxyacetic acid content (on dry basis), %4-chlorophenoxyacetic acid melting point range, ℃
Loss on drying, %
Water-insoluble matter, %
Arsenic content (as As), %
Heavy metal content (as Pb), %
Test method
HG 2302-- 92
154~156
0. 000 05
Unless otherwise specified, the reagents and water used in this standard refer to analytically pure reagents and steaming water or water of corresponding purity that meet the current national standards or industry standards.
Standard solutions, impurity standard solutions, preparations and products used in the test shall be prepared in accordance with the provisions of GB601, GB602 and GB603 unless otherwise specified.
4.1 Identification test
4.1.1 Reagents and solutions
Hydrochloric acid solution: (1+1);
Sulfuric acid solution: (1→9);
Potassium bromide: meet the requirements of infrared absorption spectrum determination, Congo red test paper.
Instruments and equipment
Platinum wire: diameter of about 0.8mm, with a straight line at the top; gas lamp or alcohol lamp;
Infrared spectrophotometer;
Agate mortar;
Glass filter crucible: filter plate pore size 5~15μm. 4.1.3 Preparation of sample
Weigh about 10g sample into a 400mL beaker, add 300mL water, and heat to dissolve. After the sample is dissolved, add 20mL sulfuric acid solution and stir with a glass rod to complete the acidification. Filter the precipitate obtained after acidification with a glass filter crucible and wash the precipitate with distilled water until there is no free acid (check with Congo red paper, the blue color almost disappears). Put the crucible together with the precipitate in an oven and bake at 110±2℃ for 2h. Take out and cool in a desiccator for use.
4.1.4 Identification method
Take 1~~2mg of the sample prepared in 4.1.3 in an agate mortar, mix and grind with about 100mg of dry potassium bromide, put it into a forming device, apply 490~980MPa pressure to the tablet surface, press it into tablets after 5~8min, put the tablets into an infrared spectrophotometer for infrared absorption spectrum measurement, and there should be absorption peaks near the wave numbers of 1700cm-1, 1600cm-1 (double peaks), 1230cm-1, 1080cm-1, 825cm-1, and 700cm-1.
b. Weigh about 5g of the sample, add a small amount of hydrochloric acid solution to make it into a paste, light a gas lamp or alcohol lamp, dip a small amount of the sample with the top of the platinum wire about 5mm, and immediately send it into a colorless flame in the horizontal direction for testing. The flame color reaction is yellow and lasts for about 4s. 542
4.2 Determination of sodium 4-chlorophenoxyacetic acid content
4.2.1 Principle
HG 2302--92
4-chlorophenoxyacetic acid sodium is acidified to 4-chlorofluorophenoxyacetic acid, and phenol anhydride is used as an indicator to titrate it with a sodium hydroxide standard titration solution. The content of sodium 4-chlorophenoxyacetic acid is calculated based on the volume of the sodium hydroxide standard titration solution consumed. 4.2.2 Reagents and solutions
Ether;
Absolute ethanol: neutral;
Sulfuric acid solution (1-→9);
Standard sodium hydroxide titration solution: c(NaOH)-0.1mol/L; saturated sodium chloride solution;
Phenol indicator solution: 10g/L ethanol solution.
4.2.3 Instruments and equipment
250ml separatory funnel and general laboratory instruments. 4.2.4 Analysis steps
Weigh 0.3-0.4g (accurate to 0.0002g) of the sample that has been dried at 110±2℃ for 2h and cooled in a desiccator, place it in a 100mL beaker, add 15mL of water, heat and stir until completely dissolved, transfer it to a 250mL separatory funnel after cooling, rinse the beaker several times with a small amount of saturated sodium chloride solution, add the washing liquid to the separatory funnel, add 1mL of sulfuric acid solution to the separatory funnel, shake for 1min, cool to room temperature, then add 40mL of ether, shake for 1min, remove the ether vapor in the funnel in time during shaking, let it stand for stratification, and carefully place the lower water layer into the second separatory funnel. Add 25mL of ether to the second separatory funnel, repeat the above operation for the second extraction, place the water layer in the third separatory funnel, and extract it for the third time with 25mL of ether. Combine the second and third ether extracts in the first separatory funnel, and rinse the other two separatory funnels with a small amount of ether. Combine the washing liquid into the first separatory funnel. Then, wash the ether extract several times with 10mL of saturated sodium fluoride solution each time until the washing liquid is added with two drops of sodium hydroxide standard titration solution, and the phenolic acid indicator turns pink (generally washed four times). Transfer the ether extract to a 250mL conical flask, and rinse the separatory funnel with a small amount of ether. Combine the ether washing liquid in the 250mL conical flask, and then place the conical flask in a 40~60℃ water bath. After the ether is evaporated, use 30mL of ethanol to completely dissolve the sediment in the conical flask, add 2~3 drops of phenolphthalein indicator solution, and titrate with sodium hydroxide standard titration solution until it turns pink. The end point is that it does not turn pink after 15s. 4.2.5 Expression and calculation of results
The mass percentage X of sodium 4-chlorophenoxyacetic acid is calculated according to formula (1): Xt=cxv×0. 208 6×100
actual concentration of sodium hydroxide standard titration solution, mol/L; where: c-—
volume of sodium hydroxide standard titration solution consumed by the titration sample, mL, mass of the sample, g;
0. 208 6-
（1）
The mass of sodium 4-chlorophenoxyacetic acid equivalent to 1.00mL of sodium hydroxide standard titration solution [c(NaOH）=1.000mol/L), expressed in grams.
Allowable difference: The difference between the results of two parallel determinations shall not exceed 0.2%, and the arithmetic mean shall be taken as the determination result. 4.3 Determination of melting point range of 4-fluorophenoxyacetic acid 4.3.1 Instruments and equipment
a. Precision thermometer: temperature range 140~160℃, graduation value 0.1℃; b. Heat bath filled with glycerol.
4.3.2 Analysis steps
The melting point range of 4-chlorophenoxyacetic acid is determined according to the capillary method in GB617, using the sample prepared in 4.1.3 for determination. 543
4.4 Determination of loss on drying
4.4.1 Instruments
Weighing bottle: diameter 45mm, height 25mm. 4.4.2 Analysis steps
HG 2302---92
Weigh 2-3g of the sample (accurate to 0.001g), place it in a weighing bottle that has been dried to a constant weight, put it in an oven, and dry it at 105-110℃ for 2h. After taking it out, put it in a desiccator, cool it to room temperature, and weigh it. 4.4.3 Expression and calculation of results
The mass percentage X of the drying loss is calculated according to formula (2): Xz=ml=m2 ×100
Where: m,-the mass of the sample before drying, g; m2
the mass of the sample after drying, g. www.bzxz.net
Allowable difference: The difference between the results of two parallel measurements shall not exceed 0.05%, and the arithmetic mean is taken as the measurement result. 4.5 Determination of water-insoluble content
4.5.1 Instrument
Glass filter crucible: filter plate pore size 5~15μm. 4.5.2 Analysis steps
(2)
Weigh 5g of the sample (accurate to 0.001g), place it in a 250mL beaker, add 200mL of water and heat it to dissolve it, transfer the entire solution into a glass filter crucible with a constant weight and filter it, so that all the water-insoluble matter is transferred into the crucible, wash the precipitate with hot water until the solution is neutral, and place it together with the precipitate in an oven at 105~110℃ to dry until constant weight. 4.5.3 Expression and calculation of results
Water-insoluble mass percentage X: Calculate according to formula (3): X, =
Mass of glass filter crucible and water-insoluble matter, name, where: ma
mz——Mass of glass filter crucible, g;
ms—Mass of sample, g.
Allowable error: The difference between the results of two parallel determinations shall not exceed 0.02%, and the arithmetic mean shall be taken as the determination result. 4.6 Determination of arsenic content
4.6.1 Sample treatment
Perform in accordance with the provisions of wet digestion in Article 1.4.2.1 of GB8450. 4.6.2 Analysis steps
Perform in accordance with the provisions of quantitative determination in Article 1.5.3 of GB8450. 4.7 Determination of heavy metal content
4.7.1 Sample treatment
Perform in accordance with the provisions of dry digestion in Article 5.2.2 of GB8451. 4.7.2 Analysis steps
(3)
Pipette 10mL (equivalent to 1g sample) of the sample solution after sample treatment in Article 4.7.1, and perform in accordance with the provisions of GB8451. The standard is to accurately pipette 1ml of lead standard solution (1.0ml is equivalent to 10μg lead). 544
5 Inspection rules
HG 2302—92
5.1 This product shall be inspected by the quality inspection department of the manufacturer. The manufacturer shall ensure that the products shipped meet the requirements of this standard. Each batch of products shipped must be accompanied by a product quality inspection certificate. 5.2 The user has the right to inspect whether the quality of the received products meets the requirements of this standard in accordance with the provisions of this standard. 5.3 The production output of each shift of the manufacturer is a batch.
5.4 Sampling method: Samples are selected according to 3×N of the total number of packaging boxes (bags) in each batch. The number of small batches shall not be less than 5 boxes (bags). The number of samples in each box (bag) shall not be less than 10 small packages, but the total amount of samples in each batch shall not be less than 150g. After mixing the sample thoroughly, use the quartering method to reduce it to 75g and pack it into two clean, dry wide-mouth bottles with ground mouths. Label them with the manufacturer name, product name, production date or batch number and sampling date. Send one copy to the laboratory for analysis and keep one copy for inspection for three months. 5.5 If one indicator does not meet the standard requirements during the inspection, re-sample from two times the packaging for re-inspection. If only one indicator does not meet the requirements of this standard, the whole batch of products will be unqualified. 5.6 When the supply and demand parties have objections to the product quality, they can negotiate with each other or handle it in accordance with the relevant provisions of the "Interim Measures for National Product Quality Arbitration Inspection".
5.7 Determination of the inspection results
It is carried out according to the rounded value comparison method in GB1250. 6 Marking, packaging, transportation and storage
6.1 The packaging of this product shall be marked with the following: manufacturer name, address, product name, trademark, production date, batch number, net weight, standard number and "food additives". Each batch of products shall be accompanied by a certificate of product quality compliance with the requirements of this standard. 6.2 This product shall be packed in plastic packaging bags for food and sealed with heat and pressure. The weight of each small package can be 1.78g, 1.27g and 0.71g respectively. The outer layer can be packed in paper boxes or plastic bags, with 100 small packages in each box or bag. 6.3 When transporting this product, attention should be paid to moisture-proof and heat-proof. It shall not be mixed or transported with toxic and hazardous substances. 6.4 This product shall be stored in a cool, dry and ventilated warehouse and shall be protected from moisture, heat and sunlight. Shelf life is 2 years. Additional remarks:
This standard is proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Beijing Chemical Industry Research Institute of the Ministry of Chemical Industry and Food Hygiene Supervision and Inspection Institute of the Ministry of Health. This standard was drafted by Nanjing Electrochemical Plant. The main drafters of this standard are Xia Dingguo and Wang Huazhi.
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