Some standard content:
National Standard of the People's Republic of China
40% Dimethoate emulsifiable concentrate
4o% Dimethoate emulsifiable concentrateSubject content and scope of application
GB15583—1995
This standard specifies the technical requirements, test methods, inspection rules, and requirements for marking, packaging, transportation and storage of dimethoate emulsifiable concentrate. This standard applies to the emulsifiable concentrate prepared by dissolving dimethoate technical and emulsifier in a suitable solvent. 2
Cited standards
GB/T 601
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T 1600
Method for determination of moisture content in pesticides
GB/T 1603
GB/T 1604
GB/T 1605
GB3796
GB4838
3 Technical conditions
Method for determination of stability of pesticide emulsions
Rules for acceptance of pesticides
Sampling methods for commercial pesticides
General rules for pesticide packaging
Emulsifiable concentrate pesticide packaging
3.1 Appearance: This product should be a homogeneous liquid. If crystals are found due to low temperature storage, place this product at 20℃ for 24h and it should return to its original state after shaking.
3.2 Dimethoate emulsifiable concentrate shall also meet the following requirements: Item
Dimethoate content, % (m/m)
Water content, % (m/m)
Acidity (in terms of H,SO4), % (m/m)
Emulsion stability (diluted 200 times)
Low temperature stability"
Hot storage stability 1)
Note: 1) It shall be inspected at least once every six months.
4 Test method
Unless otherwise specified, the reagents used in this test are of analytical grade and the water used shall meet the third-grade water specifications in GB/T6682. State Administration of Technical Supervision 199 Approved on 5-06-12, implemented on 1996-02-01
4.1 Determination of Dimethoate EC
4.1.1 Identification test
GB15583—1995
When there is doubt about the identification of the active ingredient using the prescribed test method, at least another method shall be used for identification. Gas chromatography: This identification test can be carried out simultaneously with the determination of the dimethoate content. The relative deviation between the retention time of the main peak of the sample solution and the retention time of dimethoate in the standard solution under the same conditions should be within 1.5%. Infrared spectroscopy: There should be no obvious difference between the infrared absorption spectrum of the active ingredient separated from the sample and the standard sample . T100t
4.1.2 Determination of dimethoate content
4.1.2.1 Gas chromatography
4.1.2.1.1 Summary of the method
Infrared spectrum of dimethoate standard sample
The sample was dissolved in acetone, and n-tricosane (or di-n-pentyl terephthalate) was used as the internal standard. A glass column filled with 3% OV-17/Chromosorb W-HP and a hydrogen flame ionization detector were used to separate and determine the dimethoate emulsifiable concentrate by gas chromatography. 4.1.2.1.2 Reagents and solutions
Solvent: acetone (GB/T686);
Dimethoate Standard sample: known content ≥ 99.0% (m/m); internal standard: n-tricosane (or di-n-pentyl terephthalate), should not contain impurities that interfere with analysis; stationary phase: 0V-17
Carrier: ChromosorbW-HPDMCS, 180～250μm. Internal standard solution: weigh 0.56g of n-tricosane (or 0.8g of di-n-pentyl terephthalate) and place it in a 100mL volumetric flask, add acetone to dissolve, dilute to the scale, and shake well. Tighten the stopper and store at room temperature. 4.1.2.1.3 Instrument
Gas chromatograph: with FID detector;
Chromatographic column: 1 mX2mm(id) glass column;
GB15583-1995
Column filling: OV-17 coated on Chromosorb W-HP DMCS (180～250μm). Stationary liquid: carrier 1:3:100(m/m)
Chromatographic processor
Glass wool: silanized
4.1.2.1.4 Preparation of chromatographic column
a. Coating of stationary liquid
Accurately weigh 0.060g of 0V-17 stationary liquid into a 250mL beaker, add an appropriate amount (slightly larger than the volume of the carrier) of chloroform to completely dissolve it, pour in 2.0g of the carrier, shake gently to mix well and evaporate the solvent to dryness. Then place the beaker in an oven at 110℃ for 1h, take it out and place it in a desiccator to cool to room temperature before loading the column. b. Filling of chromatographic column
Connect a funnel to the outlet of the washed and dried chromatographic column, and fill the prepared filler into the column in batches, while constantly tapping the column wall until it is filled to 1.5 cm from the column outlet. Move the funnel to the inlet of the chromatographic column, plug a small ball of silanized glass wool at the outlet, connect it to the vacuum pump through a rubber tube, turn on the vacuum pump, continue to slowly add the filler, and constantly tap the column wall to make it evenly and tightly filled. After filling, also plug a small ball of glass wool at the inlet end and press it appropriately to keep the column filler from moving. c. Aging of chromatographic column
Connect the inlet end of the chromatographic column to the vaporization chamber, do not connect the outlet end to the detector first, pass the carrier gas (N,) at a flow rate of 20 mL/min, raise the temperature to 230°C in stages, and age at this temperature for at least 48 hours. d. Passivation of the chromatographic column
After the chromatographic column is aged, lower the column temperature to about 140°C, and use a 50μL syringe to inject 5% (or 10%) dimethyldifluorosilane toluene solution (or other silanization reagent) into the vaporization chamber, 20μuL each time, 30min interval, 8 times in total, and finally stay for at least 2h. After passivation, connect the column outlet to the detector. 4.1.2.1.5 Gas chromatography operating conditions
Temperature: column chamber, 160°C, vaporization chamber, 200°C; detector chamber, 250°C. Gas flow rate: carrier gas (N2 is preferably high-purity nitrogen) 30mL/min; hydrogen, about 30mL/min; air, about 300mL/min; retention time: dimethoate, about 3.6min; n-tricosane, about 9.7min (di-n-pentyl terephthalate, about 8.7min). The above operating conditions are typical operating parameters. According to the characteristics of different instruments, the given operating parameters can be appropriately adjusted to obtain the best effect.
GB15583—1995
Figure 2 Gas chromatogram of dimethoate emulsifiable concentrate (with n-tricosane) 1 Solvent (acetone); 2-dimethoate; 3 Internal standard (n-tricosane) Figure 3 Gas chromatogram of dimethoate emulsifiable concentrate (with di-n-pentyl terephthalate) 1-Solvent (acetone); 2-dimethoate; 3-Internal standard (di-n-pentyl terephthalate) 4.1.2.1.6 Determination steps
a. Preparation of standard solution
GB15583—1995
Weigh about 0.1g (accurate to 0.0002g) of dimethoate standard sample, place it in a stoppered glass bottle, accurately transfer 5mL of internal standard solution with a pipette, and shake.
b. Preparation of sample solution
Weigh a sample containing about 0.1g of dimethoate (accurate to 0.0002g), place it in a stoppered glass bottle, accurately transfer 5mL of internal standard solution with a pipette, and shake well.
c. Determination
Under the selected chromatographic conditions, after the instrument baseline is stable, repeatedly inject the standard solution, calculate the repeatability of the relative response value of each needle, and when the relative response value of two adjacent needles changes less than 1.5%, perform gas chromatography analysis in the following order: standard solution; sample solution; sample solution; standard solution. 4.1.2.1.7 Calculation
Average the ratio of the peak area of dimethoate to the internal standard in the two needles of sample solution and the two needles of standard solution before and after the sample. The mass percentage of dimethoate X1 is calculated according to formula (1): X1 = r2miP
Wherein: ri-the average value of the peak area ratio of dimethoate to the internal standard in the standard solution, r2-the average value of the peak area ratio of dimethoate to the internal standard in the sample solution; ml-the mass of the dimethoate standard, g;
m2-the mass of the sample, g,
-the content of the dimethoate standard, % (m/m). 4.1.2.1.8 Allowable difference
The difference between the results of two parallel determinations should not exceed 0.8%. Take the average value and report it as the result. 4.1.2.2 Thin layer-bromination method (arbitration method) 4.1.2.2.1 Method summary
The sample is subjected to thin layer chromatography to separate dimethoate from impurities, and the band containing dimethoate is scraped off and then determined by bromination method. 4.1.2.2.2 Reagents and solutions
Anhydrous ethanol (GB/T678),
Potassium bromate
Potassium bromide
Potassium iodide
(GB/T 686);
(GB/T 690);
(GB/T 650);
(GB/T 649);
(GB/T1272): 30% aqueous solution;
Sulfuric acid (GB/T625) solution: 1+4 (V/V). Take 1 part of sulfuric acid and slowly add it to 4 parts of water under stirring, let it cool for later use; (1)
Potassium bromate-potassium bromide solution: c(1/6KBrO3)=0.15mol/L. Weigh 4.2g potassium bromate and 40g potassium bromide, dissolve in 1000ml water, shake well,
sodium thiosulfate (GB/T637) standard titration solution: c(Na2SO)=0.1mol/L, palladium chloride indicator solution: 1g/L. Weigh 0.1g palladium chloride, dissolve in 1mL concentrated hydrochloric acid, dilute to 100mL with 50% ethanol aqueous solution; starch indicator solution: 5g/L. Weigh 1.0g soluble starch, add 10mL water, inject into 200mL boiling water under stirring, and then boil slightly for 2 min, and let stand. Take the upper clear liquid for use;
developing agent: benzene + acetone = 7+3 (V/V);
silica gel G: particle size 10~40um.
4.1.2.2.3 Apparatus
Chromatography cylinder;
Chromatography plate: 20cm×20cm smooth glass plate; Volumetric flask (calibrated): 25mL;
Iodine volumetric flask: 500mL;
GB15583-1995
Pipette (calibrate the capacity according to the actual operating conditions): 1mL; Pipettor;
Suction filtration and pressure reducing device;
Dryer;|| tt||Absorbent cotton: Wash with ethanol and water, dry and set aside; 4.1.2.2.4 Determination steps
a. Preparation of chromatography plate
Weigh about 20g of silica gel G, add about 40mL of water in a mortar, grind into a uniform paste, pour evenly on a pre-cleaned 20cmX20cm glass plate, and gently vibrate to remove bubbles, dry it horizontally, and then put it in a 130℃ oven to dry for half an hour, take it out, and put it in a desiccator for later use.
b. Preparation of sample solution
Weigh 1.8~2.0g of sample (accurate to 0.0002g), put it in a 25mL volumetric flask, dissolve it with ethanol and dilute it to the scale, and shake it.
c. Thin layer separation
Take an activated chromatography plate, and use a 1mL pipette to place 1mL of the sample solution in a straight line at 2.5cm from the bottom and 1.5cm on both sides. After the solvent evaporates, scrape off 5cm wide silica gel on both sides of the chromatography plate, and then stand the plate upright in a chromatography cylinder filled with saturated vapor of the developing agent. The depth of the chromatography plate immersed in the solvent is controlled to be 0.5-1.0cm. When the developing agent rises to a height of about 15cm, take out the chromatography plate and put it in a fume hood to evaporate the solvent. Use palladium chloride to develop the color, mark the outline of the dimethoate band area, and transfer all this silica gel to the absorber, wipe the glass plate with a small amount of water-moistened absorbent cotton, and put the absorbent cotton into the absorber together, connect the absorber to a 500ml iodine volume bottle, and connect it to a suction filtration and decompression device, use 75mL boiling water five times (15mL each time) to elute and filter into a 500mL iodine volume bottle, and rinse the bottle wall with a small amount of distilled water. Accurately add 25 ml of 0.15 mol/L potassium bromate-potassium bromide solution, add 10 mL of 1+4 sulfuric acid, plug the bottle tightly, shake well, and seal with a small amount of water. Place at 28±1°C for 15 minutes, add 10 mL of 30% potassium iodide aqueous solution, shake for 2 minutes, titrate with 0.1 mol/L sodium thiosulfate standard solution until it turns light yellow, add 3 mL of 5 g/L starch indicator solution, and continue to titrate until the solution fades, which is the end point. Perform a blank test under the same conditions. 4.1.2.2.5 Calculate the mass percentage X of dimethoate in the sample according to formula (2): X, = c(V- V) X 0. 016 38
Wherein: V,--the volume of sodium thiosulfate standard solution consumed in the blank test, mL; V--the volume of sodium thiosulfate standard solution consumed in the sample titration, mL; C, the actual concentration of sodium thiosulfate standard titration solution, mol/L; m--the mass of the sample, g;
(2)
0.01638--the mass of dimethoate expressed in grams equivalent to 1.00mL sodium thiosulfate standard titration solution (cNazS.0)-1.00mol/L).
4.1.2.2.6 Allowable difference
The difference between the results of two parallel determinations shall not exceed 0.6%. Take the average value and report it as the result. 4.2 Determination of moisture
Determine according to the Karl Fischer method in GB/T1600 standard (trace moisture meter with equivalent accuracy is allowed). 4.3 Determination of acidity
4.3.1 Reagents and solutions
GB15583-1995
Sodium hydroxide (GB629) standard titration solution, c(NaOH)=0.02mol/L: indicator solution: 1g/L bromocresol green ethanol solution mixed with 2g/L methyl red ethanol solution (3+1). 4.3.2 Determination steps
Weigh 1g of sample to an accuracy of 0.002g, place in a 250mL conical flask, add 30mL of 50% ethanol aqueous solution, shake to dissolve the sample, add 3 drops of indicator solution, and titrate with sodium hydroxide standard titration solution until the color changes from red to bright green as the end point. Perform a blank determination at the same time.
Acidity X of the sample expressed as a percentage by mass: calculated according to formula (3): X = cV-Ve) × 0 049 × 100
Wherein: t-bzxz.net
Actual concentration of sodium hydroxide standard titration solution, mol/L; Volume of sodium hydroxide standard titration solution consumed in titrating the sample solution, mL; V. —Volume of sodium hydroxide standard titration solution consumed in titrating the blank solution, mL; m
Mass of the sample, g;
· (3)
0.049-—Mass of sulfuric acid in grams equivalent to 1.00mL sodium hydroxide standard titration solution (c(NaOH)=1.000mol/L).
4.4 Emulsion stability test
Performed according to GB/T1603. No floating oil on the top, no sinking oil or precipitation below is qualified. 4.5 Low temperature stability test
Put 50mL of the sample in a 100mL beaker, cool it to 0±1℃ by appropriate methods, and keep it at this temperature for 1h. During this period, stir slowly with a glass rod from time to time. It is qualified if there is no solid or oily precipitation. 4.6 Hot storage stability test
4.6.1 Instrument
Constant temperature box (or constant temperature water bath), 54±2℃; 50mL of an ampoule (or a stoppered glass bottle that can still be sealed at 54℃); medical syringe, 50mL.
4.6.2 Determination steps
Use a syringe to inject about 30mL of the emulsifiable concentrate sample into a clean ampoule (or glass bottle) (avoid the sample from contacting the bottleneck), place the ampoule in an ice-salt bath for cooling, and quickly seal it with a high-temperature flame (avoid the evaporation of the solvent). Seal at least two bottles and weigh them separately. Place the sealed container in a metal container, and then place the metal container in a 54 ± 2℃ constant temperature box (or water bath) for 14 days. Take out and weigh them respectively. For samples whose weight has not changed, test the specified items within 24 hours. 4.6.3 Allowable relative decomposition rate
After hot storage, the allowable decomposition rate of 40% dimethoate EC is ≤10%: The relative decomposition rate of dimethoate EC during hot storage (% (X)) is calculated according to formula (4): X, = × 100
Where: X,——is the dimethoate content measured on the sample before hot storage, %; X--is the dimethoate content measured on the same sample after hot storage, %. The samples before and after hot storage should be measured at the same time. 5 Inspection rules
5.1 Sampling method
The sampling method for emulsion and liquid state in GB/T1605 shall be followed. The sampling packages shall be determined by random method, and the final sampling volume shall generally be not less than 250mL.
5.2 Acceptance rules
Acceptance shall be carried out in accordance with GB/T1604 standard.
6 Marking, packaging, transportation and storage
GB15583-1995
6.1 The packaging and labeling of dimethoate emulsifiable concentrate shall comply with the relevant provisions of GB3796 and GB4838. 6.2 Dimethoate emulsifiable concentrate shall be packaged in brown glass bottles with stoppers and caps, with a net weight of 0.5kg or 1kg per bottle, and cushioned with anti-vibration nets, foam plastics, straw or corrugated paper, and tightly arranged in calcium plastic boxes, cartons or wooden boxes to prevent damage from impact. No more than 20 bottles per box. 6.3 Other forms of packaging may be used according to user requirements or agreement reached between the supply and demand parties, but they must comply with the relevant requirements of GB4838.
6.4 During transportation and storage, moisture and sunlight should be strictly prevented and good ventilation should be maintained. It should not be mixed with food, seeds, and feed. Avoid contact with the skin and prevent inhalation through the mouth and nose.
6.5 Packages should be stored in ventilated and dry warehouses, and the stacking method should comply with the principles of safety and convenient handling. 6.6 Safety: Dimethoate is an organophosphorus insecticide that inhibits cholinesterase. It is toxic if swallowed or inhaled. It can be absorbed through the skin and contact with the skin should be avoided. When handling this product, wear protective gloves and gas masks and wear clean protective clothing. After using the medicine, rinse with soap and water.
This product should be kept out of the reach of children and away from food, animal feed and its containers. If poisoning occurs, consult a doctor. Atropine and antiphosphorus poison are effective antidotes. If necessary, artificial respiration should be performed. 6.7 Warranty period: Under the specified storage and transportation conditions, the warranty period of dimethoate EC is two years from the date of production. During the warranty period, the effective content shall not be less than 39.0% within half a year, not less than 38.0% within one year; and not less than 36.0% within two years. During the warranty period, the acidity shall not be greater than 0.7%.
Additional remarks:
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is technically managed by the Shenyang Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Shenyang Chemical Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Jiang Minyi, Li Xiujie, Mei Baogui, Wang Xuecheng, Hou Yukai, Qiu Chengguo, and Liu Chunchun. From the date of implementation of this standard, the former Ministry of Chemical Industry standard HG2--1212-79 "Dimethoate EC" shall be invalid. 650
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