Some standard content:
GB18172.1--2000
Chapter 3 and Chapter 5 of this standard are mandatory, and the rest are recommended. This standard is formulated on the basis of domestic enterprise standards and relevant materials in accordance with the requirements of GB/T1.1--1993 "Guidelines for Standardization Work Unit 1: Drafting and Expression Rules of Standards Basic Provisions for Standardization". Appendix A of this standard is the appendix of the standard. bzxZ.net
This standard is proposed by the State Administration of Petroleum and Chemical Industry of the People's Republic of China. This standard is technically managed by Shenyang Chemical Industry Research Institute. This standard is interpreted by the Secretariat of the National Pesticide Standardization Technical Committee. The responsible drafting units of this standard: Shenyang Chemical Industry Research Institute, Hunan Nantian Industrial Co., Ltd. The participating drafting units of this standard: Beijing Chenyang Plant Protection Preparation Factory The main drafters of this standard: Wang Yufan, Liu Yong, Xing Hong, Liu Yaoqiu, Wang Yinzhong, Xiao Dongliang, Jiang Zhiguo. 672
Part 1:
National Standard of the People's Republic of China
Chlorothalonil smoke powder-GranualarsOther names, structural formulas and basic physicochemical parameters of the active ingredient chlorothalonil in this product are as follows:ISO common name: Chlorothalonil
CIPAC digital code: 288
Chemical name: 2,4,5,6-tetrachloro-1,3-dicyanobenzeneStructural formula:
Empirical formula: CN,Cl4
Relative molecular mass: 265.91 (according to the 1997 international relative atomic mass)Biological activity: Bactericidal
Melting point: 250℃～251℃
Boiling point: 350℃
GB18172.1— 2000
Vapor pressure (40℃): 1.3Pa
Solubility (g/L, 25℃): 6×10-* in water, 80 in xylene, 2 in acetone, 30 in cyclohexanone and dimethylformamide, ≤10 in kerosene. Stability: Stable under normal temperature storage conditions, stable to weak alkali or weak acidic media and to light, decomposes 1 in strong alkali media. Scope
This standard specifies the requirements, test methods, and marking, labeling, packaging and storage of 45% and 30% chlorothalonil smoke powder granules. This standard applies to 45% and 30% chlorothalonil smoke powder granules made from chlorothalonil technical materials that meet the national standard GB9551 and suitable combustion aids, fuels and fillers.
2 Referenced standards
The provisions contained in the following standards are constituted as the provisions of this standard through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. GB/T1601—1993 Method for determination of pH value of pesticides GB/T1604—1995 Acceptance rules for commercial pesticides GB/T1605--1979 (1989) Sampling methods for commercial pesticides GB3796--1999 General rules for pesticide packaging
GB9551—1999 Chlorothalonil technical
GB/T16150--19952
Method for determination of fineness of pesticide powders and wettable powders Approved by the State Administration of Quality and Technical Supervision on July 31, 2000 and implemented on March 1, 2001
3 Requirements
3.1 Appearance: uniform loose powder, without lumps. 3.2 Chlorothalonil smoke powder granules should meet the requirements of Table 1. GB18172.1—2000
Table 1 Control items of chlorothalonil smoke powder granules Items
Chlorothalonil content, %
Hexachlorobenzene content, %
Heating loss, %
pH range
Fineness (through 351 μm standard push sieve), %
Ignition test
Burning and smoking time, min
Autoignition temperature, ℃
Smoke formation rate, %
Accelerated storage test
1 Hexachlorobenzene, autoignition temperature and smoke formation rate are only tested once for the same batch of raw materials. 2 Accelerated storage test Under normal production conditions, the test should be carried out at least once every three months 4 Test method
4.1 Sampling
2. 0~~10. 0
According to the "Sampling of powders and miscible powders" 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 300g. 4.2 Identification test
4.2.1 Gas chromatography: This identification test can be carried out simultaneously with the determination of the content of thiophanate-methyl. Under the same gas chromatography operating conditions, the relative difference between the retention time of a chromatographic peak in the sample solution and the retention time of the chromatographic peak of thiophanate-methyl in the standard solution should be within 1.5%. When there is doubt about the identification of the active ingredient using the above method, other effective methods can be used for identification. 4.3 Determination of chlorothalonil content
4.3.1 Summary of method
The sample is dissolved in xylene, and o-diphenylbenzene is used as the internal standard. A glass column (or stainless steel column) filled with 5% OV-17 + 1.1% OV-225/chromosorbWAW-DMCS and a hydrogen flame ionization detector are used to separate and determine the chlorothalonil in the sample by gas chromatography.
4.3.2 Reagents and solutions
a) Xylene: no interferences found by gas chromatography analysis; b) Chlorothalonil standard sample: known content, ≥99.0%; c) Internal standard: o-diphenylbenzene, should not contain impurities that may interfere with the analysis; d) Stationary phase: OV-17, OV-225;
e) Carrier: Chromasorb WAW-DMCS, 150μm～180μm (or other carriers with equivalent performance); f) Internal standard solution: weigh 1.65g o-diphenylbenzene into a 1000ml volumetric flask, dissolve and dilute to the mark with xylene, and shake to hook. 674
4.3.3 Instruments
GB 18172.1—2000
a) Gas chromatograph: with hydrogen flame ionization detector; b) Chromatographic data processor;
c) Chromatographic column: 4 mm (id) X 2 m glass column (or stainless steel column); d) Column packing: OV-17 + OV-225 coated on Chromosorb WAW-DMCS, OV-17 + OV-225 + carrier = 5.0 + 1.1 + 93.9 (m/m);
e) Micro-injector: 10μl.
4.3.4 Preparation of chromatographic column
4.3.4.1 Coating of stationary liquid
Weigh 1.25g OV-17 and 0.275g OV-225 stationary liquid into a 250mL beaker, add an appropriate amount of acetone (slightly larger than the volume of the carrier) to completely dissolve it, slowly pour in 23.5g of the carrier, gently shake to mix evenly and evaporate the solvent, place in an oven at 110℃ for 1h, take out and place in a desiccator to cool to room temperature. 4.3.4.2 Filling of chromatographic column
Connect a small funnel to the outlet of the washed and dried chromatographic column, fill the prepared filling material into the column in batches, and tap the column wall continuously 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 glass wool at the inlet and press it properly to prevent the column filler from moving. 4.3.4.3 Aging of the chromatographic column
Connect the inlet of the chromatographic column to the vaporization chamber, do not connect the outlet to the detector for the time being, pass the carrier gas (N2) at a flow rate of 20mL/min, raise the temperature to 240℃ in stages, and keep it at this temperature for 48h. After aging, connect the outlet of the column to the detector. 4.3.5 Gas chromatography operating conditions
a) Temperature (°C): column chamber 195, vaporization chamber 280, detector chamber 280; b) Gas flow (mL/min): carrier gas (N2) 50, hydrogen 50, air 600; c) Relative retention value: thiocarbamide 1.30, o-diphenylbenzene 1.00. The above gas chromatography operating conditions are typical, and the given operating parameters can be appropriately adjusted according to the characteristics of different instruments in order to obtain the best effect. A typical gas chromatogram of thiophanate-methyl smoke powder granules is shown in Figure 1. 2
1-o-diphenylbenzene; 2-tetrachloroterephthalonitrile; 3-tetrachlorothiocarbamide Figure 1 Gas chromatogram of thiophanate-methyl smoke powder granules
4.3.6 Determination steps
4.3.6.1 Preparation of standard solution
Weigh 0.1 g of thiophanate-methyl standard sample (accurate to 0.0002 g), place it in a 25 mL volumetric flask, pipette in 20 mL of internal standard solution, and shake it.
4.3.6.2 Preparation of sample solution
GB 18172. 1-2000
Weigh 0.1g (accurate to 0.0002g) of the sample is placed in a 25mL volumetric flask, and 20mL of the internal standard solution is added using the same pipette as in 4.3.6.1. Ultrasonicate in an ultrasonic bath for 10 minutes, and filter for later use. 4.3.6.3 Determination
Under the above operating conditions, after the instrument is stable, continuously inject several needles of the standard solution, calculate the repeatability of the relative response value of each needle, until the relative response value of two adjacent needles changes by less than 1.0%, and determine in the order of standard solution, sample solution, sample solution, and standard solution. 4.3.7 Calculation
Average the ratio of the peak area of thiophanate-methyl to the internal standard in the two needles of the sample solution and the two needles of the standard solution before and after the sample. The mass fraction X(%) of chlorothalonil in the sample is calculated according to formula (1): X
wherein: ---—the average value of the ratio of the peak area of chlorothalonil to the internal standard in the standard solution; 2—the average value of the ratio of the peak area of chlorothalonil to the internal standard in the sample solution; mj—the mass of the standard sample, g;
m2—the mass of the sample, g;
P—the mass fraction of chlorothalonil in the standard sample, %. 4.3.8 Allowable difference
. (1)
The difference between the results of two parallel determinations shall not be greater than 0.9% for 45% chlorothalonil smoke powder granules and not greater than 0.6% for 30%. The arithmetic mean shall be taken as the determination result.
4.4 Determination of hexachlorobenzene content
4.4.1 High performance liquid chromatography (arbitration method) 4.4.1.1 Summary of the method
The sample was dissolved in acetonitrile, and methanol was used as the mobile phase. A liquid chromatography column with 5umODS (C1s) as the filler and a UV detector (254 nm) were used to separate and determine the hexachlorobenzene in the sample by reverse phase high performance liquid chromatography, and the external standard method was used for quantification. 4.4.1.2 Reagents and solutions
a) Methanol: chromatographically pure;
b) B: chromatographically pure;
c) Mobile phase: Methanol was filtered through a filter membrane with a pore size of 0.45μm and degassed; d) Hexafluorobenzene standard: known content, ≥99.0%. 4.4.1.3 Instruments
a) High performance liquid chromatograph: UV detector with variable wavelength; b) Chromatographic column: 4.6mm (id) × 150mm stainless steel column, filled with ODS (C1g), particle size 5μm; c) Chromatographic data processor;
d) Injector: 50μL,
e) Filter: The pore size of the filter membrane is about 0.45μm. 4.4.1.4 High performance liquid chromatography operating conditions
a) Mobile phase: methanol;
b) Column temperature: 20℃～35℃ (temperature change should be less than 2℃); c) Detection wavelength: 254nm;
d) Injection volume: 10 μL;
e) Retention time: 7.4min for hexachlorobenzene.
The above operating conditions are typical. According to the characteristics of different instruments, the given operating conditions can be appropriately adjusted to obtain the best results. A typical HPLC chromatogram of hexachlorobenzene in chlorothalonil smoke powder granules is shown in Figure 2.676
4.4.1.5 Determination steps
a) Preparation of standard solution
GB 18172. 1—2000
1chlorothalonil; 2hexachlorobenzene
Figure 2 HPLC chromatogram of hexachlorobenzene in chlorothalonil smoke powder granules Weigh 0.05g (accurate to 0.0002g) of hexachlorobenzene standard sample, place it in a 250mL volumetric flask, dissolve it with acetonitrile and dilute it to the scale, and shake it well. Use a pipette to accurately transfer 2mL of the above solution into a 50mL volumetric flask, dilute it to the scale with acetonitrile, shake it well, filter it with a 0.45μm pore size filter membrane, and store it in a sealed container.
b) Preparation of sample solution
Weigh a sample containing 0.10g (accurate to 0.0002g) of thiophanate-methyl, place it in a 10mL clean volumetric flask, dissolve it with acetonitrile and dilute it to the mark, shake it in an ultrasonic bath for 10 minutes, and filter it with a 0.45μm pore size filter membrane. c) Determination
Under the above operating conditions, after the instrument is stable, continuously inject several needles of standard solution until the peak area change between two adjacent needles is less than 10%, and then determine it in the order of standard solution, sample solution, sample solution, and standard solution. d) Calculation
Average the peak areas of hexazobenzene in the two sample solutions and the two standard solutions before and after the sample. The mass fraction of hexachlorobenzene in the sample, X, (%), is calculated according to formula (2): AzmP
X2= Armz × 625
Wherein: A,
The average value of the peak area of hexachlorobenzene in the standard solution; A2—the average value of the peak area of hexachlorobenzene in the sample solution; the mass of the hexachlorobenzene standard, g;
m2———the mass of the sample, g;
P-the mass fraction of hexachlorobenzene in the standard sample, %; 625—the ratio of the dilution volume of the standard solution to the sample solution. e) Allowable difference
The relative deviation of the results of two parallel determinations shall not exceed ±20%. . (2)
4.4.2 Capillary gas chromatography
GB 18172. 1--2000
For capillary gas chromatography, see Appendix A (Appendix to the standard). 4.5 Determination of Heating Loss
4.5.1 Apparatus
a) Weighing bottle: 30mm high, 50mm in diameter; b) Oven: 100℃±2C;
c) Desiccator.
4.5.2 Operating Procedures
Weigh 5.0g of the sample (accurate to 0.001g), place it in a weighing bottle that has been dried to constant weight, and lay it flat. Separate the weighing bottle and the bottle cap and place them in an oven. After drying for 2h, cover it, take it out and place it in a desiccator. Cool it to room temperature and weigh it. 4.5.3 Calculation
The heating loss X3(%) expressed as mass fraction shall be calculated according to formula (3): X(%) = m=\2 × 100
Wherein: m1-the mass of the sample and weighing bottle before drying, g; m2-the mass of the sample and weighing bottle after drying, g; m3-the mass of the weighed sample, g,
4.6pH value determination
shall be carried out in accordance with GB/T1601.
4.7 Fineness determination
According to the "dry sieving method" in GB/T16150-1995. 4.8 Ignition test and determination of burning and smoking time (3)
Weigh 50.0g of the sample, put it into a square lens paper bag of suitable size, wrap it, place it in a sheltered place and ignite it. If there is no flame and it does not go out during the combustion process, it burns evenly and there is no residual flame after combustion, the ignition test is qualified. The time from the time the sample is ignited and smokes to the time when it stops smoking is measured by a stopwatch as the burning and smoking time.
4.9 Spontaneous combustion Temperature determination
4.9.1 Method summary
The sample is placed on an asbestos net (test bench) suspended in a beaker, and a thermometer is inserted into the asbestos net through the socket of the beaker cover. The lower part of the beaker is an electric furnace, and the self-ignition temperature of the sample is measured while the electric furnace is continuously heating. 4.9.2 Instruments and equipment
a) Relay;
b) Contact thermometer: 0℃～300℃;
c) Mercury thermometer: 0℃~300℃;
d) Beaker: 600mL (diameter about 10cm, height about 12cm) e) Beaker cover and asbestos net (test bench): Use 0.5cm thick bakelite as the beaker cover. Use three 2mm (id) × 9cm iron wires to connect equilaterally with a 7cm diameter iron wire ring, and place an asbestos net with a diameter of 7cm on the iron wire ring, which is the test bench. Set two holes on the beaker cover, with the center of the two holes .4cm apart, insert the contact thermometer and mercury thermometer respectively. The device connection is shown in Figure 3. 4.9.3 Determination
Weigh 1.0g of sample and place it in the center of the asbestos net, then place the contact thermometer and Insert the mercury thermometer into the beaker through the two holes in the beaker cover, contact the asbestos mesh, and keep the mercury balls of the two thermometers about 0.5 cm away from the edge of the asbestos mesh. Adjust the contact thermometer knob to 100℃±5℃. After the temperature stabilizes, adjust the contact thermometer knob at a rate of 5℃~10℃ per minute. When it is close to fuming, adjust the contact thermometer knob at a rate of 1℃~2℃ per minute. Observe the sample and the mercury thermometer at the same time. When the sample is fuming, the temperature indicated by the mercury thermometer is the auto-ignition temperature.
4.9.4 Allowable deviation
GB 18172. 12000
Relay
1—Electric furnace; 2—Beaker; 3~-Asbestos mesh test bench; 4—Asbestos mesh; 5—Contact thermometer; 6—Mercury thermometer; 7~-Relay; 8—Sample; 9—Beaker cover; 10, 11, 12—Wire diagram 3 Autoignition temperature measuring instrument
The difference between the results of two parallel measurements is not greater than 5°C, and the arithmetic mean is taken as the measurement result. 4.10 Determination of smoke generation rate
4.10.1 Method Summary
Weigh a certain amount of sample, dry it in an oven, place it in a combustion bottle, ignite the sample, absorb the active ingredients in the smoke with absorption liquid, evaporate the excess solvent, add internal standard solution, take out part of the solution and determine the content of the active ingredients on gas chromatography. 4.10.2 Reagents and solutions
a) Xylene;
b) Acetone;
c) Absorption liquid: (xylene: acetone) = 1:4; d) Internal standard solution: weigh 8.5g of o-diphenylbenzene in a 1000mL volumetric flask, dissolve it in xylene and dilute to the scale, shake well; e) Standard sample solution: weigh 0.25g (accurate to 0.0002g) of thiophanate-methyl standard sample in a 50mL volumetric flask, use a pipette to transfer 10mL of internal standard solution, and add 20mL of xylene, shake well. 4.10.3 Apparatus
a) Combustion bottle: 2000mL (burner port diameter of about 6cm, burner port plug with vent valve, bottle bottom diameter of 13cm, bottle height of 20cm, vent hole diameter of 1cm);
b) Combustion table: Use 1mm thick iron wire to make a tripod with a height of 3cm and a diameter of 2cm, and place a wire mesh on the tripod;c) Absorption tube: 4 100mL tubes (inner diameter of about 2.5cm); 1 200mL tube (inner diameter of about 3.5cm); 1 500mL tube (inner diameter of about 5cm). as a buffer;
d) Constant temperature water bath;
e) Vacuum pump;
f) Evaporator: Use a contact thermometer and relay to control the water bath temperature of 95℃±5℃. The 500mL ground-mouth flask in the water bath is connected to the 500mL receiving bottle through a 30cm spherical condenser. The smoke generation and collection device is shown in Figure 4.
4.10.4 Collection of effective components in smoke
Use the prepared 2cm×3cm lens paper bag to weigh a powder sample containing about 0.30g (accurate to 0.0002g) of thiophanate-methyl, compress the sample in the bag appropriately, wrap it and place it in a constant temperature oven at 100℃±5℃ for 1h and then place it in a dryer. Place the dried sample on the combustion table in the combustion bottle. Add 100mL of absorption liquid to the first-level absorption tube, and add 50mL of absorption liquid to the second, third, fourth and fifth-level absorption tubes. Turn on the air pump to maintain 2 to 3 bubbles per second in the first-level absorption tube. After igniting the 679
GB 18172. 1--2000
sample with a match, immediately plug it with the ignition door. When it is confirmed that the sample has been burned and the combustion bottle is under negative pressure, open the vent valve to draw the smoke in the combustion bottle and the buffer bottle to the absorption tube for absorption (when the sample burns violently, resulting in the absorption liquid reflux, the vent valve of the combustion bottle plug adopts a negative pressure vent valve.), until there is no visible smoke, then evacuate for 5 minutes. Turn off the suction pump, take out the residue of the combustion sample, transfer the absorption liquid of each absorption tube to a 500mL flask, and then use 150ml. acetone to clean the inner circuit of the smoke generating device 3 times, and pour the washing liquid into the same 500ml. flask. Place the flask on the F evaporator. Evaporate until the solution is about 40mL, remove the flask to restore it to room temperature, add 10ml of internal standard solution with the same pipette as the standard sample, and shake well.
1-combustion bottle; 2-combustion table: 3-combustion bottle plug (with vent valve or negative pressure vent valve); 4-buffer bottle; 1-2, 3, 4, 5-stage absorption tube (all 100 mL) 5--1st stage absorption tube (200 mL); 6-Figure 4 Smoke generation and collection device diagram
4.10.5 Determination
4.10.5.1 Determination of active ingredient content in smoke According to the gas chromatography operating conditions in 4.3.5, after the instrument baseline is stable, continuously inject several needles of standard solution, calculate the repeatability of the relative response value of each needle, and when the relative response value of two adjacent needles changes less than 1.0%, proceed in the order of standard solution, sample solution, sample solution, standard solution. Calculate the peak area ratio of thiophanate-methyl and o-diphenylbenzene for each injection. 4.10.5.2 Calculation
The mass fraction of the effective component in the collected smoke to the original sample X, (%) is calculated according to formula (4): X
The smoke formation rate of thiophanate-methyl expressed as mass fraction X, (%) is calculated according to formula (5): X, (%) =
Wherein: mi -
The mass of the standard sample, g;
The mass of the sample, g;
, - the average value of the ratio of the peak area of thiophanate-methyl to the internal standard in the standard solution; 2 - the average value of the ratio of the peak area of thiophanate-methyl to the internal standard in the sample solution; X, - the mass fraction of thiophanate-methyl in the sample, %. 4.10.6 Allowable difference
The difference between the results of two parallel determinations should not be greater than 5%. The arithmetic mean is taken as the determination result. 4.11 Accelerated storage test
4.11.1 Method summary
Through the pressurized hot storage test, the product is aged rapidly and the performance change of the product stored at room temperature is predicted. 4.11.2 Test steps
(4)
GB18172.1-2000
Put 20g of the sample in a sealed plastic bag, place it in an oven, and store it at 54°C±2°C for 14 days. Take out the sample, put it in a desiccator, and let the sample cool to room temperature. Within 24 hours, complete the determination of the active ingredient content and smoke formation rate according to 4.3 and 4.10. The active ingredient content and smoke formation rate meet the requirements of this standard and are qualified.
4.12 Inspection and acceptance of products
Should comply with the provisions of GB/T1604. For the processing of limit values, the rounded value comparison method is adopted. 5.1 The marking, labeling and packaging of chlorothalonil smoke powder granules shall comply with the relevant provisions of GB3796-1999. 5.2 This product is packaged in plastic bags, with a net weight of 50g or 100g per bag (or box), and the outer packaging is a calcium plastic box or corrugated paper box, with a net weight of no more than 10kg per box.
5.3 Other forms of packaging may be used according to user requirements or order agreements, but they must comply with the provisions of GB3796. 5.4 The packages should be stored in a ventilated and dry warehouse. 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 low-toxic preparation. When using this product, you should wear protective gloves, masks (or gas masks), and clean protective clothing. After applying the pesticide, stay away from the place where it is set off. If poisoning occurs, ask a doctor to take emergency measures or provide treatment. 5.7 Warranty period: Under the specified storage and transportation conditions, the warranty period of chlorothalonil smoke powder granules is 2 years from the date of production. 681
A1 Method Summary
GB 18172. 1-2000
Appendix A
(Standard Appendix)
Determination of hexafluorobenzene content in chlorothalonil by capillary gas chromatography The sample is dissolved in xylene, and the hexachlorobenzene in the sample is separated and determined using a 30m×0.53mm (id) capillary column coated with 1.2μm SE-54 and a hydrogen flame ionization detector. A2 Reagents and solutions
Toluene: does not contain impurities that interfere with analysis; Hexachlorobenzene standard: known content, ≥99%, stationary liquid: SE-54.
A2.1 Instruments
a) Gas chromatograph: can use capillary chromatographic column, with splitter, hydrogen flame ionization detector and data processor; b) Capillary chromatographic column: 30mX0.53mm (id) wall coated with SE-54, liquid film thickness 1.2μm; c) Micro syringe: 5 μL.
A2.2 Gas chromatograph operating conditions
a) Temperature (C): detection chamber: 300; vaporization chamber: 300; column chamber: 200. b) Gas (kPa): carrier gas (high purity fluorine): 40; air: 50; hydrogen: 60. c) Split ratio: 70:1.
d) Range: 102.
e) Injection volume: lμl.
f) Retention time (min): hexachlorobenzene: 8.98; thiophanate-methyl: 12.58. The typical chromatogram of the sample under the above gas chromatography operating conditions is shown in Figure A1. 1-Hexachlorobenzene; 2-Chlorothalonil
Gas chromatogram of hexachlorobenzene in chlororothalonil sample GB18172.1-2000
The above gas chromatography operating conditions are typical. The given operating parameters can be appropriately adjusted according to the characteristics of different instruments and the requirements of their own conditions in order to obtain the best results. A3 Determination steps
A3.1 Solution preparation
A3.1.1 Hexachlorobenzene standard solution
Accurately weigh 0.05g (accurate to 0.0002g) of hexachlorobenzene standard in a 250ml, clean and dry volumetric flask, dissolve and dilute to the scale with toluene, and shake well. Take 5mL of the solution in a 100mL volumetric flask, dilute to the scale with toluene, and shake well. A3.1.2 Sample solution
Accurately weigh 0.45g of sample (accurate to 0.0002g) into a 10mL volumetric flask, dissolve it in toluene and dilute to the mark, and shake well. A3.2 Determination
Under the above gas chromatography operating conditions, after the instrument baseline is stable, continuously inject several needles of standard solution until the peak area change 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. A3.3 Calculation
Average the peak areas of hexachlorobenzene in the two sample solutions and the two standard solutions before and after the sample. The mass fraction of hexachlorobenzene X (%) is calculated according to formula (A1):
X = A,mz × 500
Where: A, the average value of the peak area of hexachlorobenzene in the standard solution; A2——the average value of the peak area of hexachlorobenzene in the sample solution; ml——the mass of hexachlorobenzene standard, g;
the mass of the sample,,
the mass fraction of hexachlorobenzene in the standard sample, %;
the ratio of the dilution volume of the standard solution to the sample solution. A3.4 Allowable difference
The relative deviation of two parallel determination results should not exceed ±20%. (Al)
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