Some standard content:
HG3628—1999
Cypermethrin is a synthetic pyrethroid insecticide with contact and stomach poisoning effects, a wide insecticide spectrum, and is widely used in agriculture and health.
The technical requirements of this standard refer to the United Nations Food and Agriculture Organization (FAO) pesticide specifications [FAOSpecification332/EC/S/F (1993)], and stipulate the appearance, total content of cypermethrin, moisture, emulsion stability, low temperature stability and thermal storage stability of cypermethrin emulsifiable concentrate, with indicators close to it; at the same time, the acidity specified in the FAO specifications is changed to the pH value range; the warranty period is increased. The arbitration determination method for the total content of cypermethrin in this standard refers to the International Pesticide Analysis Cooperation Council CIPAC332/EC/M/3.2, and the mobile phase is changed from heavy (isooctane * ethyl acetate) = 99.5:0.5 to sub (n-hexane * ethyl acetate) = 99:1. This standard replaces the chemical industry standard HG/T2987-1988 "Analysis Method for Cypermethrin Content" from the date of implementation. Appendix A and Appendix B of this standard are both appendices of the standard. This standard is proposed by the Policy and Regulations Department of the State Administration of Petroleum and Chemical Industry. This standard is technically managed by the Shenyang Chemical Research Institute. The main drafting unit of this standard: Shenyang Chemical Research Institute. Participating drafting units of this standard: Tianjin Longdeng Chemical Co., Ltd., Nanjing No. 1 Pesticide Factory, Jiangsu Yangnong Chemical Group Co., Ltd. The main drafters of this standard: Xu Laiwei, Zhang Xuebing, Lou Shaowei, Zou Lidong, Fan Wenzhong, Wang Quanzhong. 1246
Chemical Industry Standard of the People's Republic of China
Cypermethrin emulsifiable concentratesOther names, structural formulas and basic physicochemical parameters of cypermethrin are as follows:ISO common name: Cypermethrin
CIPAC digital code: 332
HG 3628--1999
Replace HG/T 2987—1988
Chemical name: (RS)-α-cyano-3-phenoxybenzyl (1RS)-cis-trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate
Structural formula:
CI,C—CH—CH—CH-
Empirical formula: C22HigC12NO3
Relative molecular mass: 416.31 (according to the 1993 international relative atomic mass) Biological activity: Insecticidal| |tt||Vapor pressure (20℃): 190nPa
Solubility (g/L, 20℃): 1×10-5～2×10-4 in water; 103 in hexane, 337 in ethanol, and greater than 450 in acetone, chloroform, cyclohexanone, and xylene
Stability: Stable at 220℃, neutral or acidic conditions, best at pH-4, and degraded within 1 range in soil
This standard specifies the requirements, test methods, and marking, labeling, packaging, storage and transportation of cypermethrin emulsifiable concentrate. This standard applies to cypermethrin emulsifiable concentrate prepared by dissolving cypermethrin technical and emulsifier that meet the standards in a suitable solvent.
2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by being referenced in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1600—1979（1989）Determination of moisture content in pesticides GB/T1601—1993 Determination of pH value in pesticides GB/T1603—1979(1989) Determination of stability of pesticide emulsions GB/T1604-1995 Acceptance rules for commercial pesticides GB/T1605---1979（1989）Sampling methods for commercial pesticides GB3796—1983 General rules for pesticide packaging
GB4838--1984 Packaging of emulsifiable pesticides
Approved by the State Administration of Petroleum and Chemical Industry on June 16, 1999, implemented on June 1, 2000
HG 3628—1999
GB/T 9008-1988Terms for Liquid ChromatographyColumn Liquid Chromatography and Planar Chromatography3 Requirements
3.1 Appearance: Stable homogeneous liquid, no visible suspended matter and sediment. 3.2 Cypermethrin emulsifiable concentrate shall meet the requirements of Table 1. Table 1
Cypermethrin emulsifiable concentrateControl ItemsIndicators
Total content of cypermethrin, %
Water content, %
Emulsion stability (diluted 200 times)
Low temperature stability
Hot storage stability
10% emulsifiable concentrate
Note: Low temperature stability and hot storage stability tests shall be conducted at least once every 3 months4 Test methods
4.1 Sampling
5% emulsifiable concentrate
Perform according to the "sampling of emulsions and liquid states" method in GB/T1605-1979 (1989). The sampling packages are determined by the random number table method, and the final sampling volume should be no less than 250mL. 4.2 Identification test
High performance liquid chromatography: This identification test can be carried out simultaneously with the determination of the total content of cypermethrin. Under the same chromatographic operating conditions, the retention time of the four chromatographic peaks of the sample solution and the retention time of the four chromatographic peaks corresponding to cypermethrin in the standard solution should have a relative difference within 1.5%.
Thin layer chromatography: The main spot obtained by developing the sample solution and the spot of the standard solution developed at the same time should have the same R value. Developing solvent: (n-hexane: ethyl acetate) = 99:1 or (petroleum ether: acetonitrile) = 100: 0.25. 4.3 Determination of cypermethrin content (arbitration method) 4.3.1 Method summary
The sample is dissolved in a mixed solvent of ethyl acetate/n-hexane containing methyl benzoate (internal standard). The mixed solvent of ethyl acetate/n-hexane is used as the mobile phase. Normal phase liquid spectrometry separation is performed on a chromatographic column filled with Hypersil SiO2, 5 μm. The cypermethrin content is quantified by the internal standard method. 4.3.2 Instruments and equipment
Liquid chromatograph: with ultraviolet variable wavelength detector. Chromatographic data processor.
Chromatographic column: 4.6mm (id) × 200mm stainless steel column, filled with Hypersil SiO2.5um filler. Filter: The pore size of the filter membrane is about 0.45um.
Micro-injector: 50μL.
4.3.3 Reagents and solutions
N-hexane: Chromatographic grade.
Ethyl acetate: Chromatographic grade.
Mobile phase: sub (n-hexane: ethyl acetate) = 99:1. Use a pipette to transfer 10mL of ethyl acetate into 990mL of n-hexane, shake well, filter through a 0.45μm filter membrane, and sonicate for 15min. 1248
HG 3628—1999
Methyl benzoate: It should not contain impurities that interfere with the analysis. Internal standard solution: Weigh 3.8g of methyl benzoate, dissolve it in a 1000mL volumetric flask with mobile phase and make up to volume, shake well. Cypermethrin standard: known content, greater than or equal to 98.0%. 4.3.4 Liquid chromatography operating conditions
Column temperature: room temperature (temperature difference should not exceed 2℃). Mobile phase flow rate: 1.0mL/min.
Detection wavelength: 278nm.
Injection volume: 10μL.
Retention time: methyl benzoate 4.5min; low efficiency cis E(R)-α, (1R)-cis + (S)-α, (1S)-cis J7.8min; high efficiency cis E(S)-α, (1R)-cis + (R)-α, (1S)-cis J9.2min; low efficiency trans [(R)-α, (1R)-trans + (S)-α, (1S)-trans J10.3min; high efficiency trans [(S)-α, (1R)-trans + (R)-α, (1S)-trans J11.9min (see Figure 1). 1-Internal standard (methyl benzoate);
a-Low efficiency cis [(R)-α(1R)-cis+(S)-α,(1S)-cis};b-High efficiency cis [(S)-α,(1R)-cis+(R)-α,(1S)-cis};c-Low efficiency trans [(R)-α,(1R)-trans+(S)-α,(1S)-trans];d-High efficiency trans [(S)-α,(1R)-trans+(R)-α,(1S)-trans]Figure 1 Liquid chromatogram of cypermethrin emulsifiable concentrate
The above liquid chromatography 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.
4.3.5 Determination steps
a) Preparation of standard solution
Weigh 0.05 g of cypermethrin standard (accurate to 0.0002 g),In a 15mL stoppered glass bottle, add 10mL of internal standard solution with a pipette and shake to mix.
b) Preparation of sample solution
Weigh 0.05g of the sample containing flucythrinate (accurate to 0.0002g), add 10mL of internal standard solution to a 15mL stoppered glass bottle with the same pipette as in a), and shake to mix. Then filter with a 0.45μm filter membrane. c) Determination
Under the above operating conditions, after the instrument is stable, continuously inject several injections of standard solution until the relative change of the ratio of the total area of two adjacent injections of cypermethrin to the peak area of methyl benzoate is less than 1.0%, and then analyze and determine in the order of standard solution, sample solution, sample solution, and standard solution.
4.3.6 Calculation
The total content of flucythrinate expressed as mass percentage (X,) is calculated according to formula (1): X
Wherein: r,--
HG 3628-1999
the average value of the ratio of the total peak area of flucythrinate in the standard solution to the peak area of the internal standard; 2--the average value of the ratio of the total peak area of cypermethrin in the sample solution to the peak area of the internal standard; ni\-the mass of the standard sample, g;
the mass of the sample, g;
P-the content of cypermethrin in the standard sample,%.
4.3.7 Allowable difference
The arithmetic mean is taken as the determination result. The difference between the results of two parallel determinations shall not exceed 0.4% for 10% EC and 0.2% for 5% EC.
4.4 Determination of moisture
4.4.1 Determination method
Carry out according to the Karl Fischer method in GB/T1600. It is allowed to use a moisture meter with equivalent accuracy for determination. 4.4.2 Allowable differencewww.bzxz.net
Take the arithmetic mean as the determination result. The relative difference between two parallel determination results should not exceed 30%. 4.5 Determination of pH value
Carry out according to GB/T1601.
4.6 Determination of emulsion stability
The sample is diluted 200 times with standard hard water and tested according to GB/T1603. It is qualified if there is no floating oil on the top and no precipitation on the bottom. 4.7 Low temperature stability test
4.7.1 Method summary
The sample is kept at 0℃ for 1h, and the precipitation of solid and oily substances is recorded. Continue to store at 0℃ for 7d, centrifuge, settle the solid precipitate, and record its volume.
4.7.2 Instruments and equipment
Refrigerator: Maintain (0±1)℃.
Centrifuge tube: 100mL, with a scale accuracy of 0.05mL at the bottom of the tube. Centrifuge: Matching with centrifuge tube.
4.7.3 Test steps
Take 100mL±1.0mL of sample and add it to the centrifuge tube, cool it to (0±1)℃ in the refrigerator, keep the centrifuge tube and its contents at (0±1)℃ for 1h, stir once every 15min, each time for 15s, check and record whether there is any solid or oily precipitation. Put the centrifuge tube back into the refrigerator and continue to place it at (0±1)℃ for 7d. After 7d, take out the centrifuge tube, let it stand at room temperature (not exceeding 20℃) for 3h, and centrifuge it for 15min (the relative centrifugal force at the top of the tube is 500~600g, g is the acceleration due to gravity). Record the volume of the precipitate at the bottom of the tube (accurate to 0.05mL). The precipitate is qualified if it does not exceed 0.3mL. 4.8 Thermal storage stability test
4.8.1 Instruments and equipment
Thermostatic box (or thermostatic water bath): (54±2)℃. Bottle (or glass bottle with stopper that can still be sealed at 54C). Medical syringe: 50mL.
4.8.2 Test steps
Use a syringe to inject about 30mL of emulsifiable concentrate sample into a clean bottle (avoid the sample from contacting the bottleneck), place the bottle in an ice-salt bath to cool, and quickly seal it with a high-temperature flame (avoid solvent evaporation). Seal at least 3 bottles and weigh them separately. Place the sealed bottles in a metal container, and then place the metal container in a thermostatic box (or thermostatic water bath) for 14 days. Take out and cool to room temperature, wipe the outside of the ampoule and weigh it separately. For the sample with unchanged mass, measure the total content of cypermethrin within 24 hours. The total content of cypermethrin after storage should not be less than 95% of the total content measured before storage.
4.9 Inspection and acceptance of products
HG36281999
Inspection and acceptance of products shall comply with the provisions of GB/T1604. The rounded value comparison method shall be used for the treatment of limit values. 5 Marking, labeling, packaging, transportation
5.1 The marking, labeling and packaging of cypermethrin emulsifiable concentrate shall comply with the relevant provisions of GB3796 and GB4838, and shall have the production license number and trademark.
5.2 Cypermethrin emulsifiable concentrate shall be packaged in clean and dry iron barrels with a net capacity of 200L per barrel. Or use glass bottles with inner plugs and bottle caps to package, no leakage, straw sleeves, corrugated paper or foam plastic pads between bottles, and tightly arranged in calcium plastic boxes or wooden boxes. The net content of each bottle and each box shall not be less than the quality indicated on the label.
5.3 According to user requirements or order agreements, other forms of packaging may be used, but in accordance with the relevant provisions of GB4838. 5.4 Cypermethrin emulsifiable concentrate packages should be stored in ventilated and dry warehouses. 5.5 During storage and transportation, strictly prevent moisture and sunlight, do not mix with food, seeds, and feed, avoid contact with skin and eyes, and prevent inhalation through the mouth and nose. 5.6 Safety: This product is a moderately toxic insecticide of pyrethroids, which can penetrate through the skin. When using this product, you should wear protective gloves, masks, and clean protective clothing. After use, wash with soap and water immediately. If poisoning occurs, go to the hospital for examination and treatment in time. 5.7 Warranty period: Under the specified storage and transportation conditions, the warranty period of cypermethrin emulsifiable concentrate is 2 years from the date of production. 1251
A1 Method Summary
HG 3628—1999
Appendix A
(Appendix to the standard)
Determination of cypermethrin content (liquid chromatography external standard method) The sample is dissolved in n-hexane, and n-hexane-anhydrous ether is used as the mobile phase. A stainless steel column with SiO2 as the filler and an ultraviolet detector (230 nm) are used to separate and determine the flucythrinate in the sample by normal phase high performance liquid chromatography. A2 Reagents and solutions
N-hexane: chromatographic grade.
Anhydrous ether: chromatographic grade.
Mobile phase: sub (n-hexane: anhydrous ether) = 98:2, filtered through a 0.45μm filter membrane, and ultrasonicated in an ultrasonic bath for 10 minutes. Cypermethrin standard: known content, greater than or equal to 98.0%. A3 Instruments and equipment
High performance liquid chromatograph: with variable wavelength UV detector. Chromatographic column: 150mmX3.9mm (id) stainless steel column, filled with Nova-PakSiO2 filler, particle size 5μm. Chromatographic data processor.
Filter: The pore size of the filter membrane is about 0.5um.
Micro-injector: greater than or equal to 50μL.
A4 High performance liquid chromatography operating conditions
Flow rate: 1.0mL/min.
Column temperature: room temperature (temperature difference is not greater than 2℃) Detection wavelength: 230nm.
Injection volume: 10μl.
Retention time:
Low-efficiency cis [(R)-α, (1R)-cis + (S)-α, (1S)-cis] 8.4 min; high-efficiency cis [(S)-α, (1R)-cis + (R)-α, (1S)-cis] 9.6 min; low-efficiency trans [(R)-α, (1R)-trans + (S)-α, (1S)-trans] 10.8 min; high-efficiency trans [(S)-α, (1R)-trans + (R)-α(1S)-trans] 12.3 min (see Figure A1). 1252
HG3628-1999
a—Low efficiency cis [(R)-α, (1R)-cis + (S)-α, (1S)-cis]; b—High efficiency cis [(S)-α, (1R)-cis + (R)-α, (1S)-Gu], c—Low efficiency trans [(R)-α, (1R)-trans + (S)-α, (1S)-trans], d—High efficiency trans [(S)-α, (1R)-trans + (R)-α, (1S)-trans] Figure A1 Liquid chromatogram of cypermethrin emulsifiable concentrate
The above operating parameters are typical. According to the characteristics of different instruments, the given operating parameters can be appropriately adjusted to obtain the best effect. A5 Determination steps
a) Preparation of standard solution
Weigh 0.025g (accurate to 0.0002g) of cypermethrin standard sample, place it in a 25mL volumetric flask, dissolve it with n-hexane and dilute to the mark, shake it.
b) Preparation of sample solution
Weigh 0.025g (accurate to 0.0002g) of the sample, place it in a 25mL volumetric flask, dissolve it with n-hexane and dilute it to the scale, and shake it well.
c) Determination
Under the above operating conditions, after the instrument baseline is stable, continuously inject several needles of standard solution until the change in the peak area of cypermethrin between two adjacent needles is less than 1.5%, and then determine in the order of standard solution, sample solution, sample solution, and standard solution. A6 Calculation
Average the peak areas of cypermethrin in the two needles of sample solution and the peak areas of flucythrin in the two needles of standard solution before and after the sample.
The cypermethrin content (X) expressed as a mass percentage is calculated according to formula (A1): X
the average peak area of cypermethrin in the standard solution; where: A,-
A2——the average peak area of flucythrinate in the sample solution; the mass of the cypermethrin standard, g,
the mass of the sample, g,
A7 allowable difference
the mass percentage of flucythrinate in the standard sample, %. The arithmetic mean is taken as the determination result. The difference between two parallel determination results should not be greater than 1.0%. (Al)
B1 Method Summary
HG 3628--1999
Appendix B
(Standard Appendix)
Determination of Cypermethrin Content (Gas Chromatography) The sample is dissolved in chloroform and analyzed by gas chromatography on a chromatographic column filled with 5% OV-101/Gas ChromQ using di-n-octyl sebacate (or di-isooctyl phthalate) as internal standard. B2 Reagents and Solutions
Cypermethrin Standard: known content, greater than or equal to 98.0%. Internal Standard: di-n-octyl sebacate or di-isooctyl phthalate (without impurities interfering with the analysis). Chromatographic Stationary Phase: Silicone OV-101.
Support: Gas-Chrom Q (150~180 μm). Chloroform: analytical grade.
Internal standard solution: weigh 0.9g of di-n-octyl sebacate (or 1g of di-isooctyl phthalate) in a 100mL volumetric flask, dissolve and adjust to volume with chloroform, and shake well.
B3 Instruments and equipment
Gas chromatograph: with hydrogen flame ionization detector. Chromatographic column: 0.22 mmX2m(id) glass column, filled with 5% OV-101/Gas Chrom Q (150~~180 μm). Chromatographic data processor.
Micro syringe: 10μL.
B4 Operation steps
B4.1 Preparation of chromatographic column
B4.1.1 Application of stationary liquid
Weigh 0.5g of OV-101 in a 100mL beaker, add chloroform in a fume hood to dissolve it (the amount of chloroform should be enough to just cover the support). Weigh 10g of the support, add it to the stationary liquid solution while gently shaking, and shake it from time to time to ensure uniform application. After natural evaporation, put it in a 110℃ oven to dry for 2 to 3 hours. B4.1.2 Filling of chromatographic column
Connect a small 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 1.5cm 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 tap the column wall continuously to make it evenly and tightly filled. After filling, plug a small ball of silanized glass wool at the inlet and press it properly to prevent the column filler from moving. B4.1.3 Aging of chromatographic column
Connect the inlet of the chromatographic column to the vaporization chamber of the gas chromatograph, and do not connect the detector at the outlet for the time being. Pass the carrier gas (N) at a flow rate of about 25mL/min, raise the temperature to 240℃ in stages, and keep it at this temperature for at least 24h. B4.2 Gas chromatography operating conditions
Temperature (℃): column chamber 210; vaporization chamber 270; detection chamber 280. Gas flow rate (mL/min): carrier gas (N2) 30; hydrogen 30; air 300. Relative retention time: cypermethrin 1; di-n-octyl sebacate 1.6; di-isooctyl phthalate 0.5 (see Figure B1). 1254
HG 3628—1999
1-Cypermethrin; 2-di-n-octyl ester of a type 1 diacid; 3-di-isooctyl phthalate Figure B1 Gas chromatogram of flucythrin emulsifiable concentrate
The above operating parameters are typical. According to the characteristics of different instruments, the given operating parameters can be appropriately adjusted to obtain the best effect. B4.3 Determination steps
B4.3.1 Preparation of standard solution
Weigh 0.10g of cypermethrin standard (accurate to 0.0002g) into a 15mL stoppered glass bottle, add 10mL of internal standard solution with a pipette, and shake to mix.
B4.3.2 Preparation of sample solution
Weigh 0.10g of sample containing cypermethrin (concentrated to 0.0002g) into a 15mL stoppered glass bottle, add 10mL of internal standard solution using the same pipette as in B4.3.1, and spread evenly. B4.3.3 Determination
Under the above operating conditions, after the instrument is stable, continuously inject several injections of standard solution until the relative change of the ratio of the area of cypermethrin bead between two adjacent injections to the area of the internal standard bead is less than 1.0%, and then analyze and determine in the order of standard solution, sample solution, sample solution, and standard solution.
B4.3.4 Calculation
The total content of flucythrinate expressed as mass percentage (X,) is calculated according to formula (B1): X,
Wherein: -
-the average value of the ratio of the peak area of cypermethrin to the peak area of the internal standard in the standard solution; (B1)
HG 3628-1999
r2—the average value of the ratio of the peak area of cypermethrin to the peak area of the internal standard in the sample solution; the mass of the standard, g,
m2the mass of the sample·g;
P—the content of cypermethrin in the standard sample, %. 5 Allowable error
Take the arithmetic mean as the determination result. The difference between the results of two parallel determinations shall not exceed 0.4% for 10% emulsifiable concentrate and shall not exceed 0.2% for 5% emulsifiable concentrate.5g of OV-101 is placed in a 100mL beaker, and chloroform is added to dissolve it in a fume hood (the amount of chloroform should be such that it just covers the support). Weigh 10g of the support, add it to the stationary solution while gently shaking, and shake it from time to time to ensure uniform coating. After natural evaporation, place it in a 110℃ oven to dry for 2 to 3 hours. B4.1.2 Filling of the chromatographic column
Connect a small 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 1.5cm 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 filled evenly and tightly. After filling, a small ball of silanized glass wool is also plugged into the inlet end and properly compressed to prevent the column filling from moving. B4.1.3 Aging of the chromatographic column
Connect the inlet end of the chromatographic column to the vaporization chamber of the gas chromatograph, and temporarily do not connect the outlet end to the detector. Pass the carrier gas (N) at a flow rate of about 25mL/min, and heat it to 240℃ in stages, and keep it at this temperature for at least 24h. B4.2 Gas chromatography operating conditions
Temperature (℃): column chamber 210; vaporization chamber 270; detection chamber 280. Gas flow rate (mL/min): carrier gas (N2) 30; hydrogen 30; air 300. Relative retention time: cyanothrin 1; di-n-octyl sebacate 1.6; di-isooctyl phthalate 0.5 (see Figure B1). 1254
HG 3628—1999
1-Cypermethrin;2-Di-n-octyl ester of diacid;3-Di-isooctyl phthalateFigure B1 Gas chromatogram of flucythrin emulsifiable concentrate
The above operating parameters are typical. According to the characteristics of different instruments, the given operating parameters can be appropriately adjusted to obtain the best effect. B4.3 Determination steps
B4.3.1 Preparation of standard solution
Weigh 0.10g of cypermethrin standard (accurate to 0.0002g) into a 15mL stoppered glass bottle, add 10mL of internal standard solution with a pipette, and shake to mix.
B4.3.2 Preparation of sample solution
Weigh 0.10g of sample containing cypermethrin (concentrated to 0.0002g) into a 15mL stoppered glass bottle, add 10mL of internal standard solution using the same pipette as in B4.3.1, and spread evenly. B4.3.3 Determination
Under the above operating conditions, after the instrument is stable, continuously inject several injections of standard solution until the relative change of the ratio of the area of cypermethrin bead between two adjacent injections to the area of the internal standard bead is less than 1.0%, and then analyze and determine in the order of standard solution, sample solution, sample solution, and standard solution.
B4.3.4 Calculation
The total content of flucythrinate expressed as mass percentage (X,) is calculated according to formula (B1): X,
Wherein: -
-the average value of the ratio of the peak area of cypermethrin to the peak area of the internal standard in the standard solution; (B1)
HG 3628-1999
r2—the average value of the ratio of the peak area of cypermethrin to the peak area of the internal standard in the sample solution; the mass of the standard, g,
m2the mass of the sample·g;
P—the content of cypermethrin in the standard sample, %. 5 Allowable error
Take the arithmetic mean as the determination result. The difference between the results of two parallel determinations shall not exceed 0.4% for 10% emulsifiable concentrate and shall not exceed 0.2% for 5% emulsifiable concentrate.5g of OV-101 is placed in a 100mL beaker, and chloroform is added to dissolve it in a fume hood (the amount of chloroform should be such that it just covers the support). Weigh 10g of the support, add it to the stationary solution while gently shaking, and shake it from time to time to ensure uniform coating. After natural evaporation, place it in a 110℃ oven to dry for 2 to 3 hours. B4.1.2 Filling of the chromatographic column
Connect a small 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 1.5cm 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 filled evenly and tightly. After filling, a small ball of silanized glass wool is also plugged into the inlet end and properly compressed to prevent the column filling from moving. B4.1.3 Aging of the chromatographic column
Connect the inlet end of the chromatographic column to the vaporization chamber of the gas chromatograph, and temporarily do not connect the outlet end to the detector. Pass the carrier gas (N) at a flow rate of about 25mL/min, and heat it to 240℃ in stages, and keep it at this temperature for at least 24h. B4.2 Gas chromatography operating conditions
Temperature (℃): column chamber 210; vaporization chamber 270; detection chamber 280. Gas flow rate (mL/min): carrier gas (N2) 30; hydrogen 30; air 300. Relative retention time: cyanothrin 1; di-n-octyl sebacate 1.6; di-isooctyl phthalate 0.5 (see Figure B1). 1254
HG 3628—1999
1-Cypermethrin;2-Di-n-octyl ester of diacid;3-Di-isooctyl phthalateFigure B1 Gas chromatogram of flucythrin emulsifiable concentrate
The above operating parameters are typical. According to the characteristics of different instruments, the given operating parameters can be appropriately adjusted to obtain the best effect. B4.3 Determination steps
B4.3.1 Preparation of standard solution
Weigh 0.10g of cypermethrin standard (accurate to 0.0002g) into a 15mL stoppered glass bottle, add 10mL of internal standard solution with a pipette, and shake to mix.
B4.3.2 Preparation of sample solution
Weigh 0.10g of sample containing cypermethrin (concentrated to 0.0002g), put it into a 15mL stoppered glass bottle, add 10mL of internal standard solution using the same pipette as in B4.3.1, and spread evenly. B4.3.3 Determination
Under the above operating conditions, after the instrument is stable, continuously inject several injections of standard solution until the relative change of the ratio of the area of cypermethrin bead between two adjacent injections to the area of the internal standard bead is less than 1.0%, and then analyze and determine in the order of standard solution, sample solution, sample solution, and standard solution.
B4.3.4 Calculation
The total content of flucythrinate expressed as mass percentage (X,) is calculated according to formula (B1): X,
Wherein: -
-the average value of the ratio of the peak area of cypermethrin to the peak area of the internal standard in the standard solution; (B1)
HG 3628-1999
r2—the average value of the ratio of the peak area of cypermethrin to the peak area of the internal standard in the sample solution; the mass of the standard, g,
m2the mass of the sample·g;
P—the content of cypermethrin in the standard sample, %. 5 Allowable error
Take the arithmetic mean as the determination result. The difference between the results of two parallel determinations shall not exceed 0.4% for 10% emulsifiable concentrate and shall not exceed 0.2% for 5% emulsifiable concentrate.
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