Some standard content:
Chemical Industry Standard of the People's Republic of China
HG2462.2—93
Methyl Thiophanate Wettable Powder
Published on 1993—07—05
Ministry of Chemical Industry of the People's Republic of China
Implementation on 1994—01—01
Chemical Industry Standard of the People's Republic of China
Methyl Thiophanate Wettable Powder
Subject Content and Scope of Application
HG2462.2—93
This standard specifies the technical requirements, test methods, inspection rules, and marking, packaging, transportation and storage requirements for methyl thiophanate wettable powder.
This standard applies to wettable powders made from methyl thiophanate technical material, fillers and adjuvants. Active ingredient: methyl thiophanate
Chemical name: 1,2-di-(3-methoxycarbonyl-2-thio)benzeneStructural formula:
CNH-COCHs
Molecular formula: C12H1N,0,S2
Relative molecular mass: 342.40 (1989 international relative atomic mass). 2 Reference standards
GB/T1601 Determination of hydrogen ion concentration of pesticidesGB1605 Sampling method for commercial pesticides
GB3796 General rules for pesticide packaging
GB/T5451 Determination of wettability of pesticide wettable powdersHG/T2-896 Determination of fineness of pesticide powders3 Technical requirements
3.1 Appearance: Loose powder without foreign impurities and lumps. 3.2Methyl thiophanate wettable powder should also meet the following index requirements: Item
Methyl thiophanate content, %
Suspension rate, %
Wetting time, s
pH range
50% wettable powder
Fineness [through 45um (325 mesh) sieve, %Hot storage stability1
Note, 1) Inspect at least once a quarter.
Approved by the Ministry of Chemical Industry of the People's Republic of China on July 5, 1993 50.0
70% wettable powder
Implemented on January 1, 1994
4 Test method
4.1 Determination of methyl thiophanate content
4.1.1 High performance liquid chromatography (arbitration method) 4.1.1.1 Summary of method
HG2462.2-93
The sample was dissolved in methanol, 4-hydroxybenzoic acid propyl ester was used as the internal standard, methanol + water (53 + 47) was used as the mobile phase, and the separation was carried out on a liquid chromatography column filled with Spherisorb C8 (30/127) 10μm, and the components were detected with an ultraviolet detector at a wavelength of 269nm. 4.1.1.2 Reagents and solutions
Methanol (GB683);
Water: freshly made double distilled water;
Mobile phase: methanol + water (53 + 47) (V + V), filtered through a G5 glass sand core filter funnel into a dark bottle, sealed and stored at low temperature. 4-Hydroxybenzoic acid propyl ester: no interferences were found after liquid chromatography analysis; Internal standard solution: 2g/L 4-hydroxybenzoic acid propyl ester methanol solution; Methyl thiophanate standard sample: known content, 98.5% (m/m). 4.1.1.3 Instruments
High performance liquid chromatograph: with variable wavelength UV detector; Chromatographic column: 4.6mm inner diameter, 200mm long stainless steel column, filled with Spherisorb C8 (30/127) 10um, theoretical plate number greater than 30,000,
Filter: filter membrane pore size about 0.5um;
Injector: 50uL.
4.1.1.4 Operation steps
4.1.1.4.1 Chromatographic operation conditions
Column temperature: 40℃
Mobile phase flow rate: 1.5mL/min;
Detector wavelength: 269nm;
Injection volume: 10uL;
Retention time:
Methyl thiophanate 3.0min;
4-hydroxybenzoic acid propyl ester 5.7min.
The above liquid chromatography conditions are typical operating parameters. The operating parameters can be adjusted appropriately according to the characteristics of the instrument to obtain the best results. 4.1.1.4.2 Preparation of standard solution and sample solution Weigh the standard and sample containing 0.10g of methyl thiophanate to an accuracy of 0.0001g, place them in 50mL volumetric flasks, dissolve them with methanol, dilute to the scale, and shake well. Use a pipette to transfer 5.0mL of the above solution into a 10mL stoppered vial, and then use a pipette to transfer 5.0mL of the internal standard solution into each of the above vials, shake well, and filter with a 0.5um pore size filter. Take 0.5mL of the filtrate into a 10mL stoppered vial, dilute to 10mL with mobile phase, and shake well.
4.1.1.4.3 Determination
Under the selected chromatographic conditions, after the instrument is stable, repeat the injection of the standard solution until the relative deviation of the peak area ratio of methyl thiophanate and 4-hydroxybenzoic acid lactone in two consecutive injections is less than 0.5%. Then inject in the following order: a. Standard solution;
b. Sample solution;
c. Sample solution;
Standard solution.
4.1.1.5 Calculation
HG2462.2—93
According to the chromatograms of the four injections a, b, c, and d, calculate the peak areas of methyl thiophanate and 4-hydroxybenzoic acid propyl ester ad, b, and c respectively. High performance liquid chromatogram of methyl thiophanate wettable powder 1—methyl thiophanate; 2—4-hydroxybenzoic acid propyl ester The mass percentage of methyl thiophanate (X1) is calculated according to formula (1): Xr
Wherein: -
-the average value of the peak area ratio of methyl thiophanate to 4-hydroxybenzoic acid propyl ester in the sample solution injected twice in b and c; -the average value of the peak area ratio of methyl thiophanate to 4-hydroxybenzoic acid propyl ester in the standard solution injected twice in a and d; T2
The mass of the sample,;
m2——the mass of the standard sample, g;
The purity of the standard sample, (%, m/m).
4.1.1.6 Allowable difference
The absolute difference between the results of two parallel determinations shall not exceed 1.5%. 4.1.2 Thin-layer-ultraviolet method
4.1.2.1 Summary of method
The sample is first subjected to thin-layer separation to remove impurities and then measured by ultraviolet spectrophotometry at a wavelength of 269 nm. 4.1.2.2 Reagents and solutions
Ethyl acetate (HG3-1226);
n-hexane;
Acetone (GB686);
Methanol (GB683);
Silica gel GF254 (for thin layer chromatography): particle size is 10~40um; Methyl thiophanate standard sample: known content, ≥98.5% (m/m); Developing solvent: ethyl acetate + n-hexane = 1+1 (V/V), mix well 4.1.2.3 Instruments
Ultraviolet spectrophotometer;
Chromatography cylinder;
Thin layer plate, weigh about 8g of silica gel GF254, put it in a glass mortar, add 20mL of water, grind it into a uniform paste, immediately pour it on a clean 150×180×3mm glass plate, shake it gently to make the silica gel evenly distributed on the plate, and place it horizontally to dry. Before use, place the thin layer plate in a 110℃ oven for activation for 1.0h, take it out and place it in a desiccator for later use. 3
Ultraviolet lamp: wavelength range includes 254nm;
Volume flask: 50mL;
Pipette: 1mL;
Glass frit filter funnel: G4, 25mL.
4.1.2.4 Operation stepsbzxZ.net
HG 2462.2—93
Weigh the standard sample and sample containing 0.13g of methyl thiophanate to an accuracy of 0.0001g, place them in a G4 glass frit funnel respectively, dissolve them with acetone, filter them into a 50mL volumetric flask, make up to volume, and shake them well. Pipette 1.0mL of the solution onto the thin layer plate 2cm from the bottom edge and 1cm on both sides, and spot the sample in a straight line along the 15cm edge, and use a small amount of acetone to wash the residue on the tip of the pipette on the spotting line. After the solvent evaporates, place the thin layer plate in a chromatography cylinder saturated with the developing agent, with a developing agent depth of 1 cm in the chromatography cylinder. When the developing agent front rises to 14 cm from the origin, take out the plate, and after the solvent evaporates, under ultraviolet light, draw the main band at Rt-0.35. Quantitatively transfer the main band to a G4 glass sand core filter funnel lined with double-layer quantitative filter paper, wash the silica gel in the funnel with 45 mL of methanol in batches, collect the filtrate in a 50 mL volumetric flask, dilute with methanol, and shake well. Transfer 10 mL to a 50 mL volumetric flask, dilute with methanol, and shake well. At the same time, make a blank measurement. At a wavelength of 269 nm, use the blank solution as a reference and use a 1 cm absorption cell to simultaneously measure the absorbance of the standard and sample solutions. 4.1.2.5 Calculation
The mass percentage of methyl thiophanate (X) is calculated according to formula (2): Am
Wherein, A1——absorbance of methyl thiophanate in the sample solution; A2——absorbance of methyl thiophanate in the standard solution. 4.1.2.6 Allowable difference
The absolute difference between the results of two parallel determinations should not be greater than 1.5%. 4.2 Determination of suspension rate
4.2.1 Summary of method
Weigh a sample containing 0.35g of methyl thiophanate, prepare a suspension in a measuring cylinder with standard hard water, and under specified conditions, determine the mass of methyl thiophanate in the bottom tenth of the suspension and the precipitate, and calculate its suspension rate. 4.2.2 Solution
Standard hard water, 342mg/L, prepared according to the method in GB5451. 4.2.3 Apparatus
Constant temperature water bath: 30±1℃;
Measuring cylinder: with ground stopper, 250mL. The distance between the scale lines of 0~250mL is 20.0~21.5cm, and the distance between the scale line of 250mL and the bottom of the stopper is 4~6cm;
Glass pipette: 40cm long, 5mm inner diameter, with a 2~3mm hole at the tip of one end, and the other end connected to the suction source. 4.2.4 Determination steps
Weigh the sample containing 0.35g of methyl thiophanate to an accuracy of 0.0001g, and put it into a 200mL beaker containing 50mL of standard hard water (30±1℃). Shake the beaker in a circular motion by hand for 2.0min, 120 times per minute. After the beaker is placed in a water bath for 13 minutes, the sample is quantitatively transferred to a measuring cylinder (30°C) with standard hard water at 30 ± 1°C, and diluted to 250 mL. The stopper is inserted. Invert the measuring cylinder 30 times at a speed of once every two seconds. Place the measuring cylinder vertically in a water bath without vibration and direct sunlight for 30 minutes. Then, within 10 to 15 seconds, use a pipette to draw out 9/10 of the suspension in the upper part of the measuring cylinder. When drawing liquid, the tip of the pipette should be kept a few millimeters below the liquid surface to minimize the agitation of the suspension.
Use a long pipette to draw 1/10 of the residue in the measuring cylinder into a 50 mL beaker. Rinse the bottom of the measuring cylinder with 15 mL of acetone three times (avoid washing the sticky materials on the upper part of the measuring cylinder), and transfer them to the beaker. Place the beaker in a 100°C water bath to evaporate to dryness. Use methanol to transfer the residue in the beaker to a 50mL volumetric flask, adjust the volume and shake well. Transfer 5.0mL to a 10mL stoppered vial and proceed according to 4.1.1, or transfer 1.0mL to a thin layer plate and spot it according to 4.1.2. 4
4.2.5 Calculation
HG2462.2—93
First calculate the mass of methyl thiophanate contained in 1/10 of the residue according to formula (3) or formula (4), and then calculate the suspension rate (X2) of methyl thiophanate according to formula (5):
Where: ms——the mass of methyl thiophanate contained in 1/10 of the residue, g; m4—the mass of methyl thiophanate contained in the sample for preparing the suspension, g; 111.1——conversion factor.
4.2.6 Allowable difference
The absolute difference between the results of two parallel determinations should not exceed 5%. 4.3 Determination of wetting time
According to GB/T5451.
4.4 Determination of pH value
According to the pH meter method in GB/T1601.
4.5 Determination of fineness
According to the wet sieving method in HG/T2-896.
4.6 Thermal storage stability
4.6.1 Apparatus
Beaker: 250mL, inner diameter 6~6.5cm;
Metal ball: coated with plastic, with a diameter slightly smaller than the inner diameter of the beaker, and a mass that can produce a pressure of 2450Pa on its bottom surface; Oven: 54±2℃.
4.6.2 Operation steps
(3)
· (4)
..*.*..(5)
Weigh 20g of sample into a beaker and flatten it without using pressure. Place the metal block on the surface of the sample in the beaker and store the beaker in an oven at 54±2℃ for 14 days. Take out the beaker, remove the round block, and cool it to room temperature in a desiccator without desiccant. Within 24 hours, test according to the methods specified in Articles 4.1, 4.2, 4.3, 4.4 and 4.5 of this standard. If the results meet the technical requirements of the standard, the thermal stability of the product is qualified.
5 Inspection rules
5.1 Methyl thiophanate wettable powder should be inspected by the quality supervision and inspection department of the production unit. The production unit should ensure that all methyl thiophanate shipped from the factory meets the requirements of this standard. 5.2 The business unit and the user unit have the right to verify whether the received methyl thiophanate wettable powder meets the requirements of this standard in accordance with the provisions of this standard.
5.3 The sampling method shall be carried out in accordance with GB1605. The sample shall be divided into two bottles, one bottle shall be submitted to the quality supervision and inspection department for inspection, and the other bottle shall be sealed. 5.4 In the inspection results, when there are indicators that do not meet the requirements of this standard, samples shall be taken from twice the amount of packaging for re-inspection. In the results of the re-inspection, if even one indicator does not meet the requirements of this standard, the entire batch of methyl thiophanate wettable powder is an unqualified product. 5.5 When the supply and demand parties have disputes over product quality, they can be resolved through negotiation between the two parties or by the statutory inspection agency, in accordance with the inspection methods specified in this standard, to conduct arbitration analysis. 6 Marking, packaging, transportation and purchase and storage
6.1 The marking and packaging of methyl thiophanate wettable powder shall comply with the relevant provisions of GB3796 and be trademarked. 5
HG 2462.293
6.2 During transportation and storage, it should be strictly protected from moisture and sunlight, and maintained in good ventilation. It should not be mixed with food, seeds, and feed, and should avoid contact with the skin and inhalation through the mouth and nose.
6.3 The warranty period of this product is two years, that is, under the specified packaging and storage conditions, within two years from the date of production, the content of methyl thiophanate shall not be less than 68.8% for 70% wettable powder; not less than 49.0% for 50% wettable powder; and the suspension rate shall not be less than 60%. o
A1 Method Summary
HG2462.2—93
Appendix A
CIPAC Method (reference)
The sample was dissolved in methanol, 4-hydroxybenzoic acid propyl ester was used as the internal standard, ethyl + methanol + water (25+25+50) was used as the mobile phase, and the separation was carried out on a liquid chromatography column filled with Lichrosorb RP-8 (10um) or Zorbox BPC8 (7~8um), and the components were detected with a UV detector at a wavelength of 269nm.
Instruments and reagents
Liquid chromatograph: with variable wavelength UV detector; Chromatographic column: stainless steel column with inner diameter of 4.6mm and length of 250mm, filled with Lichrosorb RP-8 (10um) or Zorbox BPC8 (7~8um), theoretical plate number of more than 5,000;
Filter: with 0.45um filter element;
Ultrasonic bath;
Acetonitrile: HPLC grade;
Methanol: HPLC grade;
Water: distilled water or deionized water,
Mobile phase: acetonitrile + methanol + water (25+25+50), filtered and degassed with a 0.45um filter before use. Methyl thiophanate standard: analytical standard with known purity; 4-hydroxybenzoic acid propyl ester: high grade;
Internal standard solution: 0.5g 4-hydroxybenzoic acid propyl ester methanol solution. Chromatographic operating conditions
Column temperature: 40℃;
Mobile phase flow rate: 1mL/min (about 4MPa);Detector wavelength: 269nm;
Detection sensitivity: make the peak reach 80% to 90% of the full scaleInjection volume: 20uL;
Recording instrument paper speed: 0.5cm/min.
Retention time:
Methyl thiophanate: 6.7min;
4-hydroxybenzoic acid propyl ester: 10.4min.
Preparation of A4 standard solution and sample solution
Weigh the standard and sample containing 0.10g of methyl thiophanate into a 200mL volumetric flask, add 150mL of methanol, place in an ultrasonic bath for 10min, cool and dilute to volume with methanol, and shake well. Transfer 5mL of the upper clear liquid to a 50mL volumetric flask, accurately transfer 5mL of the internal standard solution, adjust the volume with the mobile phase, and shake well. Before injection, filter with a filter with a 0.45um filter element. The standard sample must be prepared daily. A5
Determination steps
Under the specified chromatographic conditions, after the instrument is stable, repeatedly inject the standard solution until the relative deviation of the peak area (or peak height) ratio of methyl thiophanate and 4-hydroxybenzene 7
HG2462.2—-93
propyl formate in two consecutive injections is less than 0.5%. Then inject in the following order: a.Standard solution;
Test solution;
c. Test solution,
Standard solution.
According to the chromatograms of the four injections a, b, c, and d, calculate the peak areas (or peak heights) of methyl thiophanate and 4-hydroxybenzoic acid propyl ester in a, d and b, c respectively.
The mass percentage content of methyl thiophanate (X1) is calculated according to formula (A1): Timw
Wherein: π——the average value of the peak area (or peak height) ratio of methyl thiophanate and 4-hydroxybenzoic acid propyl ester in the sample solution of b and c T2——the average value of the peak area (or peak height) ratio of methyl thiophanate and 4-hydroxybenzoic acid propyl ester in the standard solution of a and d; one mass of the sample,,
the mass of the standard, name,
one purity of the standard, (%, m/m).
Additional Notes:
This standard was proposed by the Department of Science and Technology of the Ministry of Chemical Industry of the People's Republic of China. This standard was drafted by the Shenyang Institute of Chemical Industry of the Ministry of Chemical Industry. The main drafters of this standard are Wu Qi, Xu Laiwei, Xing Hong, Liu Guoxiu, Gu Shaolin, Han Guangyan, and Wang Tongling. 8
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