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1 Scope of application
The method is applicable to the determination of the suspension rate of the pesticide wettable powder.
2 Reference standard
GB601 chemical reagents Titration analysis (capacity analysis) preparation of standard solutions
Preparation of preparations and products used in GB603 chemical reagents
3 Determination of levitation rate
3 1 Method 1 (Arbitration Law)
3 1 1 Method summary: Prepare the test sample to a suitable concentration of suspension using standard hard water. Under the specified conditions, the sample was allowed to stand for 30 minutes in a measuring cylinder, and the content of the active ingredient in the bottom one tenth of the suspension was measured, and the suspension rate was calculated.
3 1 2 reagent
The reagents and water used in this standard refer to the analytical reagents and the tertiary water specified in GB6682 when no other requirements are indicated.
3 1 2 1 Magnesium oxide (GB9857): dried at 105 before use for 2 h;
3 1 2 2 calcium carbonate (GH3-1066): baked at 400 for 2 hours before use;
3 1 2 3 hydrochloric acid (GB622) solution: 0 1mol / L, 1mol / L;
3 1 2 4 sodium hydroxide (GB629) solution: 0 1mol / L;
3 1 2 5 ammonia water (GB631): 1 mol / L;
3 1 2 6 methyl red (HG3—958) indicating solution: 1g/L, prepared according to GB6034 5 6;
3 1 2 7 Stocking liquid: The preparation methods of A and B are as follows:
Solution A: c(C 2+) =0 04mol/L
Accurately weigh 4 000g of calcium carbonate in a 800mL beaker, add a small amount of water to wet, slowly add 82mL of 1mol / L hydrochloric acid solution, and stir well. After all the calcium carbonate is dissolved, add 400 mL of water, boil, remove carbon dioxide, cool to room temperature, add 2 drops of methyl red indicator solution, neutralize to orange with ammonia, transfer the solution to a 1000 mL volumetric flask, dilute to the mark with water. Mix well. Store in a polyethylene bottle for later use.
Solution B: c(Mg2+) = 0.04mol/L
Accurately weigh 1 613g of magnesium oxide, put it in 800mL beaker, add a little water to wet, slowly add 82ml of 1mol / L hydrochloric acid solution, stir well and slowly heat. After all the magnesium oxide is dissolved, add 400mL of water, boil, remove carbon dioxide. Cool to room temperature, add 2 drops of methyl red indicator solution, neutralize to orange with ammonia, transfer the solution to a 1000 mL volumetric flask, dilute to the mark with water, and mix. Store in a polyethylene bottle for later use.
3 1 2 8 Standard hard water: 342mg/L based on calcium carbonate, prepared as follows:
Pipette 68 5mLA solution and 17 0mL B solution in a 1000mL beaker, add water 800mL, add 0 1mol / L sodium hydroxide solution or 0 1mol / L hydrochloric acid solution, adjust the pH to 60 ~ 70 (measured by pH meter). Transfer this solution to a 1000 mL volumetric flask, dilute to the mark with water, and mix.
3 1 3 instruments
3 1 3 1 Measuring cylinder: 250mL, with ground glass stopper, 0! 250mL scale spacing is 20 0! 21 5cm, the distance between the 250mL scale line and the bottom of the stopper should be 4! 6cm;
3 1 3 2 glass pipette: about 40cm long, inner diameter is about 5mm, there is a hole of about 2! 3mm at the tip of one end, and the other end of the pipe is connected to the corresponding pumping source;
3 1 3 3 constant temperature water bath: 30 1 ;
3 1 3 4 stopwatch.
3 1 4 Determination step
Weigh an appropriate amount of sample 1), accurate to 0 0001g, placed in a 200mL beaker containing 50mL of standard hard water (30 1 ), shake by hand for circular motion, about 120 times per minute, for 2min, the suspension is in Place in the water bath at the same temperature for 13 min, then wash it into a 250 mL graduated cylinder with 30 1 of standard hard water, dilute to the mark, cover with a stopper, take the bottom of the cylinder as the axis, and invert the cylinder upside down 30 times in 1 min ( Invert the cylinder and return it to its original position for about 2 s). Open the stopper and place it vertically in a vibration-free constant temperature water bath for 30 minutes.
Use a pipette to remove the 9/10 (ie 225 mL) suspension of the contents within 10! 15 s. Do not shake or agitate the sediment in the cylinder, making sure that the tip of the pipette is always a few millimeters below the surface.
The content of the active ingredient in the sample and the 25 mL suspension at the bottom of the measuring cylinder was determined according to the prescribed method 2).
Note: 1) The concentration of the suspension prepared in this amount should be the highest spray concentration recommended for the wettable powder. Its sample weight is in the product standard
2) The determination of the active ingredient content should be specified in the product standard.
3 1 5 Calculation
The suspension rate of the sample X1 [% (m / m)] is calculated according to the formula (1):
m
X 1-m2
1 =10/
9 m 100
1
m
=111.1 1-m2
m ...........................(1)
1
Where: m1———the mass of the active ingredient in the sample taken from the suspension, g;
M2———The mass of the active ingredient in the 25 mL suspension at the bottom of the cylinder, g.
3 2 Method 2
3 2 1 Method summary
The sample to be tested is prepared into a suspension of appropriate concentration with standard hard water, and allowed to stand in a measuring cylinder for 30 minutes under the specified conditions, and the content of the active ingredient in the nine-ninth suspension of the upper part of the measuring cylinder is measured, and the suspension rate of the sample is calculated.
3 2 2 reagent
Same as 3 1 2 .
3 2 3 instruments
Same as 3 1 3 .
3 2 4 Determination step
Weigh the appropriate amount of sample 1), accurate to 0 0001g, directly placed in a measuring cylinder containing 50mL of standard hard water (30 1 ), gently shake the sample to disperse, then dilute to the mark with 30 1 standard hard water, cover plug. With the bottom of the measuring cylinder as the axis, the measuring cylinder is turned upside down 30 times in 1 min (the measuring cylinder is inverted and returned to the original position once, about 2 s). Open the stopper and place it vertically in a non-vibrating thermostatic water bath to avoid direct sunlight for 30 minutes. Transfer the 9/10 (ie 225 mL) suspension of the contents to a clean 500 mL flask with a pipette for 10! 15 s. Do not shake or agitate the sediment in the cylinder to ensure that the top of the straw is always below the surface. A few millimeters. After thoroughly shaking the 225 mL suspension in the flask, quickly remove a certain volume (VmL) of the test solution, determine the content of the active ingredient or determine the content of the active ingredient in the bottom 25 mL suspension and precipitate 2).
Note: 1) The concentration of the suspension prepared in this amount should be the highest spray concentration recommended for the wettable powder. Its sample weight is in the product standard
Provide for it.
2) The determination of the active ingredient content should be specified in the product standard.
3 2 5 Calculation
3 2 5 1 When measuring the upper 225 mL suspension, the sample suspension rate X2 [% (m/m)] is calculated according to formula (2):
m
X 2
2=250
V m 100 ...........................(2)
1
Where: V—the volume of the suspension used for the analysis, mL;
M1—the mass of the active ingredient in the sample taken to prepare the suspension, g;
M2——— the mass of the active ingredient in the VmL suspension, g;
250———To prepare the total volume of the suspension, mL.
3 2 5 2 When the bottom 25mL suspension is measured, the suspension rate of the sample is calculated according to the formula (1) of 3 1 5 .
Appendix A
Hard water determination method
(Supplementary)
A1 reagents and solutions
A1 1 ammonia-ammonium chloride buffer solution A: pH+10, prepared according to GB6034 4 8;
A1 2 chrome black T indicator liquid: 5g / L, according to GB6034 5 24;
A1 3 Ethylenediaminetetraacetic acid disodium standard solution: c (EDTA) =0 01mol / L, prepared and calibrated according to GB6014 15 .
A2 Determination of total hardness
Accurately transfer 25mL water sample to the conical flask, add 10mL ammonia-ammonium chloride buffer solution A (pH +10) and 5 drops of chrome black T indicator solution (5g / L), with ethylenediaminetetraacetic acid disodium standard The titration solution was titrated until the solution changed from purple to pure blue. Also make a blank test.
The total hardness (calculated as calcium carbonate, in mg/L) is calculated according to formula (A1):
Total hardness c( V
= 1-V0) 0 1001
25 00 106 ..................(A1)
Where: c—the actual concentration of the standard titration solution of disodium edetate, mol/L;
V1—the volume of the standard titration solution of disodium edetate disodium in the titration sample solution, mL;
V0———the volume of the standard titration solution of disodium edetate disodium solution consumed by titration blank solution, mL;
25 00———Removing the volume of hard water, mL;
0 1001——— with 100 mL of ethylenediaminetetraacetic acid disodium standard titration solution [ c(EDTA) =1 000mol/
L] is equivalent to the mass of calcium carbonate expressed in grams.
Appendix B
Use instructions
(reference piece)
This standard method is equivalent to the FAO (FAO) standard, ie CIPAC (International Pesticide Analysis)
Collaboration Committee) MT15 1.
The difference is:
The purity of B1 calcium carbonate and magnesium oxide reagents was changed from analytically pure to 99%.
B2 After preparing the suspension, the cylinder was thermostated for 30 minutes with the cylinder stopper open. CIPACMT15 1 method is to play
Open the plug, no specific regulations.
1 Scope of application
The method is applicable to the determination of the suspension rate of the pesticide wettable powder.
2 Reference standard
GB601 chemical reagents Titration analysis (capacity analysis) preparation of standard solutions
Preparation of preparations and products used in GB603 chemical reagents
3 Determination of levitation rate
3 1 Method 1 (Arbitration Law)
3 1 1 Method summary: Prepare the test sample to a suitable concentration of suspension using standard hard water. Under the specified conditions, the sample was allowed to stand for 30 minutes in a measuring cylinder, and the content of the active ingredient in the bottom one tenth of the suspension was measured, and the suspension rate was calculated.
3 1 2 reagent
The reagents and water used in this standard refer to the analytical reagents and the tertiary water specified in GB6682 when no other requirements are indicated.
3 1 2 1 Magnesium oxide (GB9857): dried at 105 before use for 2 h;
3 1 2 2 calcium carbonate (GH3-1066): baked at 400 for 2 hours before use;
3 1 2 3 hydrochloric acid (GB622) solution: 0 1mol / L, 1mol / L;
3 1 2 4 sodium hydroxide (GB629) solution: 0 1mol / L;
3 1 2 5 ammonia water (GB631): 1 mol / L;
3 1 2 6 methyl red (HG3—958) indicating solution: 1g/L, prepared according to GB6034 5 6;
3 1 2 7 Stocking liquid: The preparation methods of A and B are as follows:
Solution A: c(C 2+) =0 04mol/L
Accurately weigh 4 000g of calcium carbonate in a 800mL beaker, add a small amount of water to wet, slowly add 82mL of 1mol / L hydrochloric acid solution, and stir well. After all the calcium carbonate is dissolved, add 400 mL of water, boil, remove carbon dioxide, cool to room temperature, add 2 drops of methyl red indicator solution, neutralize to orange with ammonia, transfer the solution to a 1000 mL volumetric flask, dilute to the mark with water. Mix well. Store in a polyethylene bottle for later use.
Solution B: c(Mg2+) = 0.04mol/L
Accurately weigh 1 613g of magnesium oxide, put it in 800mL beaker, add a little water to wet, slowly add 82ml of 1mol / L hydrochloric acid solution, stir well and slowly heat. After all the magnesium oxide is dissolved, add 400mL of water, boil, remove carbon dioxide. Cool to room temperature, add 2 drops of methyl red indicator solution, neutralize to orange with ammonia, transfer the solution to a 1000 mL volumetric flask, dilute to the mark with water, and mix. Store in a polyethylene bottle for later use.
3 1 2 8 Standard hard water: 342mg/L based on calcium carbonate, prepared as follows:
Pipette 68 5mLA solution and 17 0mL B solution in a 1000mL beaker, add water 800mL, add 0 1mol / L sodium hydroxide solution or 0 1mol / L hydrochloric acid solution, adjust the pH to 60 ~ 70 (measured by pH meter). Transfer this solution to a 1000 mL volumetric flask, dilute to the mark with water, and mix.
3 1 3 instruments
3 1 3 1 Measuring cylinder: 250mL, with ground glass stopper, 0! 250mL scale spacing is 20 0! 21 5cm, the distance between the 250mL scale line and the bottom of the stopper should be 4! 6cm;
3 1 3 2 glass pipette: about 40cm long, inner diameter is about 5mm, there is a hole of about 2! 3mm at the tip of one end, and the other end of the pipe is connected to the corresponding pumping source;
3 1 3 3 constant temperature water bath: 30 1 ;
3 1 3 4 stopwatch.
3 1 4 Determination step
Weigh an appropriate amount of sample 1), accurate to 0 0001g, placed in a 200mL beaker containing 50mL of standard hard water (30 1 ), shake by hand for circular motion, about 120 times per minute, for 2min, the suspension is in Place in the water bath at the same temperature for 13 min, then wash it into a 250 mL graduated cylinder with 30 1 of standard hard water, dilute to the mark, cover with a stopper, take the bottom of the cylinder as the axis, and invert the cylinder upside down 30 times in 1 min ( Invert the cylinder and return it to its original position for about 2 s). Open the stopper and place it vertically in a vibration-free constant temperature water bath for 30 minutes.
Use a pipette to remove the 9/10 (ie 225 mL) suspension of the contents within 10! 15 s. Do not shake or agitate the sediment in the cylinder, making sure that the tip of the pipette is always a few millimeters below the surface.
The content of the active ingredient in the sample and the 25 mL suspension at the bottom of the measuring cylinder was determined according to the prescribed method 2).
Note: 1) The concentration of the suspension prepared in this amount should be the highest spray concentration recommended for the wettable powder. Its sample weight is in the product standard
2) The determination of the active ingredient content should be specified in the product standard.
3 1 5 Calculation
The suspension rate of the sample X1 [% (m / m)] is calculated according to the formula (1):
m
X 1-m2
1 =10/
9 m 100
1
m
=111.1 1-m2
m ...........................(1)
1
Where: m1———the mass of the active ingredient in the sample taken from the suspension, g;
M2———The mass of the active ingredient in the 25 mL suspension at the bottom of the cylinder, g.
3 2 Method 2
3 2 1 Method summary
The sample to be tested is prepared into a suspension of appropriate concentration with standard hard water, and allowed to stand in a measuring cylinder for 30 minutes under the specified conditions, and the content of the active ingredient in the nine-ninth suspension of the upper part of the measuring cylinder is measured, and the suspension rate of the sample is calculated.
3 2 2 reagent
Same as 3 1 2 .
3 2 3 instruments
Same as 3 1 3 .
3 2 4 Determination step
Weigh the appropriate amount of sample 1), accurate to 0 0001g, directly placed in a measuring cylinder containing 50mL of standard hard water (30 1 ), gently shake the sample to disperse, then dilute to the mark with 30 1 standard hard water, cover plug. With the bottom of the measuring cylinder as the axis, the measuring cylinder is turned upside down 30 times in 1 min (the measuring cylinder is inverted and returned to the original position once, about 2 s). Open the stopper and place it vertically in a non-vibrating thermostatic water bath to avoid direct sunlight for 30 minutes. Transfer the 9/10 (ie 225 mL) suspension of the contents to a clean 500 mL flask with a pipette for 10! 15 s. Do not shake or agitate the sediment in the cylinder to ensure that the top of the straw is always below the surface. A few millimeters. After thoroughly shaking the 225 mL suspension in the flask, quickly remove a certain volume (VmL) of the test solution, determine the content of the active ingredient or determine the content of the active ingredient in the bottom 25 mL suspension and precipitate 2).
Note: 1) The concentration of the suspension prepared in this amount should be the highest spray concentration recommended for the wettable powder. Its sample weight is in the product standard
Provide for it.
2) The determination of the active ingredient content should be specified in the product standard.
3 2 5 Calculation
3 2 5 1 When measuring the upper 225 mL suspension, the sample suspension rate X2 [% (m/m)] is calculated according to formula (2):
m
X 2
2=250
V m 100 ...........................(2)
1
Where: V—the volume of the suspension used for the analysis, mL;
M1—the mass of the active ingredient in the sample taken to prepare the suspension, g;
M2——— the mass of the active ingredient in the VmL suspension, g;
250———To prepare the total volume of the suspension, mL.
3 2 5 2 When the bottom 25mL suspension is measured, the suspension rate of the sample is calculated according to the formula (1) of 3 1 5 .
Appendix A
Hard water determination method
(Supplementary)
A1 reagents and solutions
A1 1 ammonia-ammonium chloride buffer solution A: pH+10, prepared according to GB6034 4 8;
A1 2 chrome black T indicator liquid: 5g / L, according to GB6034 5 24;
A1 3 Ethylenediaminetetraacetic acid disodium standard solution: c (EDTA) =0 01mol / L, prepared and calibrated according to GB6014 15 .
A2 Determination of total hardness
Accurately transfer 25mL water sample to the conical flask, add 10mL ammonia-ammonium chloride buffer solution A (pH +10) and 5 drops of chrome black T indicator solution (5g / L), with ethylenediaminetetraacetic acid disodium standard The titration solution was titrated until the solution changed from purple to pure blue. Also make a blank test.
The total hardness (calculated as calcium carbonate, in mg/L) is calculated according to formula (A1):
Total hardness c( V
= 1-V0) 0 1001
25 00 106 ..................(A1)
Where: c—the actual concentration of the standard titration solution of disodium edetate, mol/L;
V1—the volume of the standard titration solution of disodium edetate disodium in the titration sample solution, mL;
V0———the volume of the standard titration solution of disodium edetate disodium solution consumed by titration blank solution, mL;
25 00———Removing the volume of hard water, mL;
0 1001——— with 100 mL of ethylenediaminetetraacetic acid disodium standard titration solution [ c(EDTA) =1 000mol/
L] is equivalent to the mass of calcium carbonate expressed in grams.
Appendix B
Use instructions
(reference piece)
This standard method is equivalent to the FAO (FAO) standard, ie CIPAC (International Pesticide Analysis)
Collaboration Committee) MT15 1.
The difference is:
The purity of B1 calcium carbonate and magnesium oxide reagents was changed from analytically pure to 99%.
B2 After preparing the suspension, the cylinder was thermostated for 30 minutes with the cylinder stopper open. CIPACMT15 1 method is to play
Open the plug, no specific regulations.
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