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Chemical Industry Standard of the People's Republic of China
HG2200—91
Methyl isofenphos EC
Published on November 18, 1991
Ministry of Chemical Industry of the People's Republic of China
Implementation on July 1, 1992
W2
Chemical Industry Standard of the People's Republic of China
Methyl isofenphos EC
Subject Content and Scope of Application
HG2200—91
This standard specifies the technical requirements, test methods, inspection rules, and packaging, marking, transportation and storage of methyl isofenphos EC. This standard applies to methyl isofenphos EC prepared from methyl isofenphos technical and suitable emulsifiers and solvents. Active ingredient: Methyl isofosfosinate
Chemical name: N-isopropyl-O-methyl-O-[(2-isopropoxycarbonyl)phenyl]thiophosphoramidate Structural formula:
(CH3)2CHNH
Molecular formula: CuH220,PSN
Relative molecular mass: 331.3 (International relative atomic mass in 1987) Reference standard
GB1600
GB1603|| tt||GB1604
GB1605
GB3796
GB4838
3 Technical requirements
Method for determination of moisture content in pesticides
Method for determination of stability of pesticide emulsions
Pesticide acceptance rules
Sampling method for commercial pesticides
General rules for pesticide packaging
Emulsifiable concentrate pesticide packaging
3.1 Appearance: Brown-yellow oily liquid.
3.2 Methyl isothioate emulsifiable concentrate shall meet the following technical requirements: Item
Content of active ingredient
Acidity (calculated as HSO)
Emulsion stability
Approved by the Ministry of Chemical Industry of the People's Republic of China on November 18, 1991COOCH(CH3)2
%(m/m)
Implementation on July 1, 1992
W.bzsoso:com Thermal stability1)
Low temperature stability
Note: 1) is a type inspection item with an inspection period of half a year. 4 Test method
4.1 Determination of methyl isofenphos
4.1.1 Summary of method
HG2200-91
%(m/m)
The sample is dissolved in ethyl acetate, di-n-butyl sebacate is used as the internal standard, and a hydrogen flame ionization detector is used to perform gas chromatography on a 5%oV-3 packed column.
4.1.2 Reagents and solutions
4.1.2.1 Ethyl acetate (HG3-1226); 4.1.2.2 Standard sample of methyl isofenphos: known content; 4.1.2.3 Di-n-butyl sebacate: must not contain impurities that interfere with the chromatographic analysis 4.1.2.4 Stationary liquid: 0V-3;
4.1.2.5 Carrier: 101 silanized white carrier (180~250um) Dimethyldichlorosilane: for chromatography ;
4.1.2.7 Internal standard solution: weigh 5g (accurate to 0.0001g) of di-n-butyl sebacate in a 250mL volumetric flask, dissolve and dilute to the mark with ethyl acetate, and mix well;
4.1.2.8 Standard sample solution: weigh about 0.2g (accurate to 0.0001g) of methyl isothioate standard in a 10mL volumetric flask, use a pipette to accurately add 5mL of internal standard solution, dissolve and dilute to the mark with ethyl acetate, and mix well. 4.1.3 Instruments
4.1.3.1 Gas chromatograph: with hydrogen flame ionization detector; 4.1.3.2 Chromatographic column: 1m long, 3mm inner diameter glass column (or stainless steel column), filled with 5% 0V-3/101 silanized white support (180~250um);
4.1.3.3 Recorder: 5mV (or data processor); 4.1.3.4 Micro-injector: 5uL.
4.1.4 Operation steps
4.1.4.1 Preparation of chromatographic column
4.1.4.1.1 Coating of stationary liquid: Weigh 0.50g 0V-3 stationary liquid, put it in a 200mL beaker, add about 30mL chloroform, stir with a glass rod to completely dissolve 0V-3. Then add 10.0g of 101 silanized white support, shake the beaker gently by hand to make the support completely immersed in the solution, place the beaker under an infrared lamp to heat, and shake the beaker while heating. When the solvent evaporates to near dryness, place it in a 120℃ oven to dry for 2 hours, take it out and place it in a dryer for use.
4.1.4.1.2 Silanization of glass column (or stainless steel column) and glass lining of vaporization chamber: inject 5% silanization reagent (DMCS) toluene solution into an empty, clean, dry glass column and lining, soak for 15 minutes, and then release the silane reagent toluene solution. The column and lining are washed with toluene, methanol and distilled water in turn, and finally washed with acetone, and dried in a 110℃ oven for 2 hours. 4.1.4.1.3 Filling of chromatographic column: connect a small funnel to the inlet of the silanized and dried glass column (or stainless steel column), wrap the outlet with gauze, and connect it to the vacuum pump with a hose. Turn on the vacuum pump and add the column filler from the funnel in batches while tapping the column wall continuously to fill the column evenly and tightly. Remove the column and plug both ends of the column with an appropriate amount of silanized glass wool. 4.1.4.1.4 Aging of the column: Connect the inlet end of the column to the vaporization chamber, and temporarily do not connect the outlet end to the detector. Raise the temperature to 260°C in stages at a carrier gas flow rate of about 15mL/min, and age at this temperature for at least 24h. After cooling, connect the column outlet end to the detector. 2
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Temperature:
Column chamber 210℃,
Vaporization chamber 270℃;
Gas flow rate:
Carrier gas (N2) 60mL/min;
Hydrogen 45mL/min;
Air 450mL/min,
Attenuation:
16×10° (data processor 4×10°); Paper speed:
HG2200—91
2.5mm/min (data processor 2mm/min); Injection volume:
Retention time:
Methyl isothioate is about 6.9min, internal standard is about 9.7min. Gas chromatogram of methyl isofenphos emulsifiable concentrate
1-methyl isofenphos;2-di-n-butyl sebacate3
HG2200-91
The above chromatographic operating conditions are typical conditions for GC-7A gas chromatograph. Appropriate adjustments can be made for different types of instruments to obtain the best results.
4.1.4.3 Preparation of sample solution
Weigh about 0.2g of methyl isofenphos emulsifiable concentrate sample (accurate to 0.0001g) into a 10mL volumetric flask, accurately add 5mL of internal standard solution with a pipette, dilute to the mark with ethyl acetate, and mix well. 4.1.4.4 Determination
After the instrument is stable, repeatedly inject 0.6uL of methyl isofenphos standard solution until the ratio of the response values of two adjacent needles (the ratio of methyl isofenphos peak area/internal standard peak area) is basically stable (the change is within 2%), and then analyze in the following order: a. Standard solution;
b. Sample solution;
c Sample solution;
d. Standard solution.
4.1.4.5 Calculation:
Average the obtained response values of ad and b, c, and calculate the mass percentage of methyl isofenphos in the sample X1 according to formula (1): T2.mi·
Wherein: i——the average value of the response value ratio of methyl isofenphos to the internal standard in the standard solution; 12——the average value of the response value ratio of methyl isofenphos to the internal standard in the sample solution; mi
the sample weight of methyl isofenphos standard, g;
the mass percentage of methyl isofenphos standard. 4.1.5 Allowable difference
The difference between the results of the second determination should not be greater than 1.0%. 4.2 Determination of moisture
The determination shall be carried out according to the Karl Fischer method in the method for determining moisture in pesticides in GB1600. 4.3 Acidity determination
4.3.1 Reagents and solutions
4.3.1.1 Anhydrous ethanol (GB678);
4.3.1.2 Standard titration solution of sodium hydroxide (GB629): c(NaOH)=0.02mol/L;4.3.1.3 0.1% bromophenol blue indicator solution: weigh 0.100g bromophenol blue, dissolve it in ethanol, and dilute it to 100mL with ethanol. 4.3.2 Operation steps
Weigh 2~3g sample (accurate to 0.001g) was placed in a 150mL conical flask, 20mL of anhydrous ethanol and 3 drops of bromophenol blue indicator were added, and the solution was titrated with sodium hydroxide standard titration solution until the blue color was reached, which was the end point. At the same time, a blank determination was performed. 4.3.3 Calculation
The acidity X2 of methyl isofenphos EC expressed as a mass percentage is calculated according to formula (2): Xz=c(VV)X0. 049
Wherein: c—actual concentration of sodium hydroxide standard titration solution, mol/L, V1—volume of sodium hydroxide standard titration solution consumed when titrating the sample, mL, 4
W.HG2200-91
V2—volume of sodium hydroxide standard titration solution consumed when titrating the blank, mL, m——mass of the sample, g;
0.049——mass of sulfuric acid equivalent to 1.00mL sodium hydroxide standard titration solution (c(NaOH)=1.000mol/L), expressed in grams.
4.4 Determination of emulsion stability
The determination method for stability of pesticide emulsions in GB1603 was followed, with a dilution factor of 500 times. The temperature of the constant temperature water bath is controlled at 30±1℃. 4.5 Hot storage stability test
4.5.1 Instrument
4.5.1.1 Oven or water bath: temperature control accuracy is 54±2℃; 4.5.1.2 Ampoule: capacity is about 50mL, long neck. 4.5.2 Determination
Pour about 30mL of sample into a clean ampoule, seal it with a gas lamp, place it in a 54±2℃ oven or water bath, and store it for 14 days. The relative decomposition rate of the active ingredient of the sample after hot storage is not more than 5% compared with that before hot storage. 4.6 Low temperature stability test
4.6.1 InstrumentbZxz.net
Ice water bath or refrigerator: control the temperature to 0±1℃. 4.6.2 Operation steps
Take about 50mL of sample in a 100mL beaker, put it in a refrigerator or ice water bath, keep the temperature at 0±1℃, and leave it for 1h. Stir once every 15 minutes for 0.5 minutes each time. Then observe whether there is solid or oily matter precipitated in the cup. If not, it is qualified. 5 Inspection rules
5.1 Carry out in accordance with GB1604 pesticide acceptance rules. Within the two-year guarantee period, the mass percentage of methyl isofenphos shall not be less than 95% of the marked content.
5.2 Carry out in accordance with GB1605 commercial pesticide sampling method 5.3 The performance of this product is equivalent to 40% methyl isofenphos EC analyzed by the original chemical method. 6 Marking, packaging, transportation and purchase and storage
6.1 The packaging and marking of methyl isofenphos EC shall be carried out in accordance with the relevant provisions of GB3796 and GB4838. 6.2 During transportation and storage, methyl isofenphos EC must be kept dry, ventilated, strictly prevented from moisture and sunlight, and must not be mixed with food, seeds, feed, etc.
Additional instructions:
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 technical supervision of Shenyang Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Shenyang Chemical Research Institute of the Ministry of Chemical Industry and Qingdao Second Pesticide Factory. The main drafters of this standard are Chen Jianli, Xu Zhenhuan, Sun Siping and Zhang Qizhong. 5
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