GB 28157-2011Acephate emulsifiable concentrates (English PDF)

1.0 O, O, S- trimethyl phosphorothioate mass fraction a /% <= 0.1

0.2 Table 1 (continued) project index 30% EC 40% EC Moisture content /% <=

0.6 Acidity content (in terms H2SO4) /% <=

0.5 Emulsion stability (200 times) Qualified Low temperature stability a qualified Thermal storage stability of a qualified When a normal production, O, O, S- trimethyl phosphorothioate content, low temperature storage stability and thermal stability test was measured at least once every three months. Test Method

4 Safety Tips. Use of this standard shall have practical experience of laboratory personnel work. This standard does not point out all of the safety issues. Make With those who have the responsibility to take appropriate safety and health practices and to ensure compliance with the relevant national regulations.

4.1 General provisions This standard reagents and water in the absence of other requirements specified, refers to three analytical reagent and GB/T 6682-2008 specified in water. The test standard titration solution, did not indicate when the other requirements, according to GB/T 601 requirements preparation and calibration. test result Determination of GB/T 8170-2008

4.3.3 Rounding the value comparison method.

4.2 Sampling According to GB/T 1605-2001 in "liquid formulations sampling" approach. Determining sample package using a random number table method; the final sample size Not less than 250mL.

2.0 Acetamide mass fraction /% <= 0.3

0.4 Methamidophos mass fraction /% <= 0.8

4.3 Identification Test Liquid chromatography

--- The identification test can be carried out simultaneously with the determination of the mass fraction of acephate. In the same chromatographic operating conditions , The sample solution to a chromatographic retention time and acephate standard solution peak retention time, the relative difference should 1.5% or less.

4.4 Determination of acephate, methamidophos acetamide and mass fraction

4.4.1 Method summary Sample dissolved in mobile phase, acetonitrile and water (pH = 3) as the mobile phase, use as filler to C18 stainless steel column and UV detector (210nm), the sample of acephate, methamidophos acetamide and reverse phase high performance liquid chromatography, external standard.

4.4.2 Reagents and solutions Acetonitrile. HPLC grade; Water. The new secondary steam distilled water; Phosphoric acid; Acephate standard. a known mass fraction w>=99.0%; Acetamide standard. a known mass fraction w>=98.0%; Methamidophos standard. a known mass fraction w>=98.0%; Sample preparation and methamidophos acetamide standard solution. Weigh acetamide standard 0.06g, methamidophos standard 0.1g (accurate to 0.0002g) placed in 50mL volumetric flask, add the mobile phase dissolved and diluted to the mark.

4.4.3 Instruments High performance liquid chromatography. a variable wavelength UV detector; Chromatographic data processor or workstation; Column. 250mm × 4.6mm (id) stainless steel column, built C18,5µm filler (or with equivalent effect column); Filter. filter pore size of about 0.45µm; Micro injector. 250µL; Ultrasonic cleaner.

4.4.4 HPLC operating conditions Mobile phase. Psi. after (acetonitrile, water) =

10.90 adjusted to pH with phosphoric acid to water is 3, mixed, filtered through a filter membrane, and Degassing; Flow rate. 1.0mL/min; Column temperature. room temperature (temperature change should not exceed 2 °C); Detection wavelength. 210nm; Injection volume. 20µL; Retention time. acetamide 3.6min, methamidophos 5.0min, acephate 5.7min. It said operating parameters are typical, according to the characteristics of different instruments, given operating parameters adjusted as appropriate, in order to obtain the best results. Typical acephate EC HPLC is shown in Figure 1. 1

--- acetamide; 2

--- methamidophos; 3

--- acephate. Figure 1 acephate EC HPLC diagram

4.4.5 Measuring step

4.4.5.1 Preparation of standard solution Weigh acephate standard 0.06g (accurate to 0.0002g) placed in 50mL volumetric flask, with a pipette Pipette 2.0mL acetyl Amine standards and methamidophos standard solution in the same volumetric flask, dissolved in mobile phase and dilute to the mark.

4.4.5.2 Preparation of sample solution Weigh containing acephate 0.06g (accurate to 0.0002g) sample, placed in 50mL volumetric flask, dissolved in mobile phase and diluted To the mark.

4.4.5.3 Determination Under these operating conditions, after the instrument is stable, continuous injection of several doses of the standard solution until the two adjacent needles acephate relative peak area After the change is less than 1.2%, according to the solution, the sample solution, the sample solution and standard sequence of the standard solution was measured.

4.4.5.4 Calculation The two front and rear needle sample solution measured sample and two doses of the standard solution of acephate (acetamide, methamidophos) peak area, respectively Averaged. Sample acephate (acetamide, methamidophos) mass fraction according to equation (1). w1 = A2 · M1 · w A1 · m2 × f (1) Where. w1

--- sample acephate (acetamide, methamidophos) mass fraction, expressed as a percentage; A2

--- sample solution, the average acephate (acetamide, methamidophos) peak area; m1

--- standard mass in grams (g); w

--- Sample acephate (acetamide, methamidophos) mass fraction, expressed as a percentage; f

--- dilution factor of acephate f = 1, acetamide and methamidophos f = 0.04; A1

--- the standard solution, the average acephate (acetamide, methamidophos) peak area; m2

--- sample mass, in grams (g).

4.4.5.5 allowable difference Acephate poor quality score of two parallel determination results shall be not more than 0.8% acetamide and methamidophos should be less than the relative difference 20%, respectively, the arithmetic mean value as a measurement result. Determination

4.5 O, O, S- trimethyl phosphorothioate mass fraction

4.5.1 Method summary Sample dissolved in mobile phase, acetonitrile and water (pH = 3) as the mobile phase, use as filler to C18 stainless steel column and UV detector (210nm), the sample of O, O, S- trimethyl phosphorothioate reverse phase high performance liquid chromatography, external standard.

4.5.2 Reagents and solutions With 4.4.2. O, O, S- trimethyl phosphorothioate Sample. A known mass fraction w>=95.0%.

4.5.3 Instruments With 4.4.3.

4.5.4 HPLC operating conditions With 4.4.4; Retention time. O, O, S- trimethyl phosphorothioate 15min. It said operating parameters are typical, according to the characteristics of different instruments, given operating parameters adjusted as appropriate, in order to obtain the best results. Typical acephate EC HPLC is shown in Figure 2. 1

--- O, O, S- trimethyl phosphorothioate. Figure 2 acephate EC HPLC diagram

4.5.5 measuring step

4.5.5.1 Preparation of standard solution Weigh O, O, S- trimethyl phosphorothioate standard 0.05g (accurate to 0.0002g) placed in 50mL volumetric flask with mobile compatibility Solution and diluted to the mark.

4.5.5.2 Preparation of sample solution Weigh containing O, O, S- trimethyl phosphorothioate 0.05g (accurate to 0.0002g) sample, placed in a 50mL volumetric flask, with the mobile Phase dissolved and diluted to the mark.

4.5.5.3 Determination Under these operating conditions, after the instrument is stable, continuous injection of several doses of the standard solution until the two adjacent needles acephate relative peak area After the change is less than 1.2%, according to the solution, the sample solution, the sample solution and standard sequence of the standard solution was measured.

4.5.5.4 Calculation The measured before and after the two-needle sample solution and sample two doses of the standard solution of O, O, S- trimethyl phosphorothioate peak area, respectively, into the Line averaging. Sample O, O, S- trimethyl phosphorothioate mass fraction according to formula (2). w2 = A2 · M1 · w A1 · m2 (2) Where.

--- w2 of the sample O, O, S- trimethyl phosphorothioate mass fraction in%;

--- The A2 in the sample solution, the average of O, O, S- trimethyl phosphorothioate peak area; m1

--- standard mass in grams (g); w

--- standard samples O, O, S- trimethyl phosphorothioate mass fraction, expressed as a percentage; The A1

4.7 Determination of the mass fraction of acidity

4.7.1 Reagents and solutions Ethanol. phi (C2H5OH) = 95%; Sodium hydroxide standard titration solution c (NaOH) = 0.02mol/L; Indicator solution. methyl red ethanol solution, rho (methyl red) = 2g/L.

4.7.2 measuring step Weigh the sample 2g (accurate to 0.0002g), placed in a 250mL Erlenmeyer flask, add ethanol 50mL, shake the sample solution solution. Add 5 drops of indicator solution, titration with sodium hydroxide standard titration solution, the solution changed from red to orange is the end. Meanwhile blank Determination.

4.7.3 Calculation The acidity of the sample according to equation (3) Calculated. w3 = c (V1-V0) · M m × 1000 × 100 (3) Where. W3

--- acidity of the sample, expressed in%; C

--- the actual concentration of sodium hydroxide standard titration solution, expressed in moles per liter (mol/L); V1

--- titration of the sample solution, the volume of consumption of sodium hydroxide standard titration solution, in milliliters (mL); V0

--- titrate blank solution, the volume of consumption of sodium hydroxide standard titration solution, in milliliters (mL); Numerical

--- the M sulfuric (H2SO4) molar mass of the units of grams per mole (g/mol), M 12H2SO ÷ 4 êê úú = 49; M

--- the quality of the sample, in grams (g).

4.8 emulsion stability test Standard hard water sample was diluted 200-fold, according to GB/T 1603 test, no oil slick measuring cylinder (cream), and precipitation of heavy oil qualified.

4.9 cryogenic stability According to GB/T 19137 in "homogeneous emulsion and liquid preparations" to. The bottom of the centrifuge tube educt volume of less than 0.3mL qualified.

4.10 Thermal storage stability test According to GB/T 19136 in "liquid formulation" to. After the thermal storage, 30%, 40% acephate EC acephate content should Not less than 90% before storage, acetamide mass fraction, mass fraction of methamidophos, emulsion stability should remain the standard requirements is qualified.

4.11 Product inspection and acceptance Shall comply with GB/T 1604's. 5 marking, labeling, packaging, storage, security, guarantee

5.1 marking, labeling, packaging Acephate EC marking, labeling and packaging should comply with the provisions of GB 4838. Acephate application with the EC within the plug and the outer cover of glass bottles, bottle net content of 250g, 500g, etc; overpack Gaisu Box or corrugated boxes, each box of net weight shall not exceed 15kg. According to user requirements or ordering agreement, you can use other forms of packaging, but Subject to the provisions of GB 4838.