GB 18058-2000 Hygienic standard for monomethylhydrazine in the atmosphere of residential areas
Some standard content:
GB18058—2000
All technical contents of this standard are mandatory. Fore
In order to implement the "Environmental Protection Law of the People's Republic of China" and the "Law of the People's Republic of China on the Prevention and Control of Air Pollution", prevent and control the pollution of the residential environment by the waste gas generated by aerospace industrial enterprises, and protect the health of the general public. This standard is formulated based on the principles of formulating residential air hygiene standards, referring to foreign research results, and based on the actual situation in my country. This standard shall be implemented on January 1, 2001. Appendix A and Appendix B of this standard are both appendices to the standard. This standard is proposed by the Ministry of Health of the People's Republic of China. The responsible drafting unit of this standard is: the Seventh Design Institute of the Ministry of Aerospace Industry; participating drafting units: the Institute of Pharmacology of the Academy of Military Medical Sciences of the Chinese People's Liberation Army, and the 101st Institute of the Ministry of Aerospace Industry. The main drafters of this standard are: Wang Xinchao, Xia Yadong, and Zhu Mingsheng. This standard is entrusted by the Ministry of Health to the Environmental Health Monitoring Institute of the Chinese Academy of Preventive Medicine to interpret. 16
1 Scope
National Standard of the People's Republic of China
Monomethyl-hydrazine in air of residential area
Hygienic standard for monomethyl-hydrazine in air of residential areaGB 18058—2000
This standard specifies the maximum permissible concentration of monomethyl-hydrazine in air of residential area and its monitoring and inspection methods. This standard is applicable to the monitoring and evaluation of the atmospheric environment in residential areas. 2 Contents of the standard
2.1 The maximum permissible concentration of monomethyl-hydrazine in air of residential area is stipulated as follows: daily average not more than: 0.006 mg/m2; any one time not more than: 0.015 mg/m2.
2.2 Monitoring and inspection methods
The monitoring and inspection methods of this standard are shown in Appendix A and Appendix B. Approved by the State Administration of Quality and Technical Supervision on April 10, 2000 and implemented on January 1, 2001
A1 Principle
GB18058-2000
Appendix A
(Appendix to the standard)
P-dimethylaminobenzaldehyde colorimetric method
Use a solid adsorbent coated with sulfuric acid to collect monomethylhydrazine in the air, and react with p-dimethylaminobenzaldehyde after desorption to generate a yellow azine compound for colorimetric quantification.
A2 Instruments
A2.1 Stoppered graduated test tube: 25mL.
A2.2 Graduated pipette: 20ml, 10mL, 5mL, 1mL. A2.3 Spectrophotometer.
A2.4 Air sampler: 0~2L/min. bzxz.net
A2.5 Sampling tube, make according to the following procedure: weigh 10.0g 40~60 mesh 101 white carrier, put it into a beaker, add 100mL distilled water, quickly heat and boil for 3min, pour out the upper turbid liquid, add distilled water to wash until the rinse liquid is clear and transparent. Filter the carrier to dryness with a Buchner funnel, then transfer it to a watch glass, spread it evenly, dry it at 70℃±1℃ for 40~50min, and transfer it to a desiccator to cool. Weigh 4.0g of the washed carrier, spread it evenly on the watch glass, use a pipette to take 11.0mL sulfuric acid-ethanol solution, evenly drop it on the carrier, air dry in a fume hood, transfer it to a constant temperature drying oven at 80C±1℃, dry it for 40min (until the carrier is loose), transfer it to a desiccator to cool to room temperature, and bottle it for later use.
Weigh 300 mg of sulfuric acid-coated support and put it into a glass sampling tube (90 mm long, 6 mm inner diameter). Fix the two ends of the support with a clean 60-meter stainless steel mesh. After installation, seal it with a polyethylene cap in time. A3 Reagents
A3.1 Sulfuric acid: high-grade pure.
A3.2 Anhydrous ethanol: high-grade pure.
A3.3 Ethanol: analytical grade.
A3.4 Monomethyl tantalum: propellant grade product with a purity of more than 98.5%. A3.5 p-Dimethylaminobenzaldehyde: analytical grade. A3.6101 White support: 40-60 mesh.
A3.7 Sulfuric acid solution: 0.15 mol/L.
A3.8 Sulfuric acid solution: 6 mol/L.
A3.9 p-dimethylaminobenzaldehyde solution: weigh 15.0g p-dimethylaminobenzaldehyde, dissolve in 500mL ethanol, add 4.2mL sulfuric acid (A3.1), shake well. It can be stored at room temperature for two weeks. A3.10 Sulfuric acid ethanol solution: add 36mL sulfuric acid solution (A3.8) to 200mL anhydrous ethanol, and then dilute to 250mL with anhydrous ethanol. A3.11 Standard solution: add about 70mL sulfuric acid solution (A3.7) to a 100mL volumetric flask, cover with a stopper, and use a syringe to accurately weigh about 0.115mL of methylhydrazine (weighed to 0.1mg) on an analytical balance by the reduction method. When weighing, seal the needle tip with a small piece of rubber. Carefully inject methylhydrazine into the volumetric flask, shake gently, and dilute to the scale with sulfuric acid solution (A3.7) after 20 minutes. Shake well to obtain a 1.0mg/mL standard stock solution, which can be stored for half a year at low temperature.
Take another 100mL volumetric flask, add about 70ml sulfuric acid solution (A3.7), 1mL standard preparation solution, and then dilute to the scale with sulfuric acid solution (A3.7) 48
GB18058—2000
. This is the standard solution, in which the content of monomethylhydrazine is about 10μg/ml. A4 Sampling
Remove the polyethylene caps at both ends of the glass sampling tube at the sampling site, connect one end to the air sampler, place the sampling tube vertically with the tube mouth downward, and collect 30~50I of air at a rate of 1l./min. After sampling, seal the two ends of the sampling tube with polyethylene caps, put it in a plastic bag, and send it to the laboratory for analysis. A5 Analysis steps
A5.1 Control test: Bring the sampling tube to the sampling site, remove the polyethylene caps at both ends but do not collect air, and seal it with polyethylene caps at the end of sampling, and keep it as a control test.
A5.2 Sample treatment: Transfer the sampled and control test supports into graduated test tubes respectively, rinse the sampling tube wall 3-4 times with a small amount of sulfuric acid solution (A3.7), let it stand for 5 minutes, add 10mL of p-dimethylaminobenzaldehyde solution, dilute to the scale with sulfuric acid solution (A3.7), invert 5 times to mix, and color at room temperature for 30 minutes.
A5.3 Drawing of standard curve: Take 7 stoppered graduated tubes, add 300mg of sulfuric acid-coated support to each, two tubes as blank, and add 0.2, 0.4, 0.6, 0.8, 1.0mL of 10μg/ml monomethylhydrazine standard solution to each tube, then add 10ml of p-dimethylaminobenzaldehyde solution to each tube and dilute to the scale with sulfuric acid (A3.7), invert 5 times to mix, color at room temperature for 30min, then use 2cm colorimetric blood, wavelength 470nm, zero with distilled water as reference, measure the absorbance of the upper clear liquid of each tube respectively, subtract the average absorbance of the blank to get the net absorbance of each solution. Draw the curve of --methylhydrazine content (μg)-absorbance on the coordinate paper. A5.4 Determination: Determine the absorbance of the sample according to the conditions and steps for making the standard curve, and find out the mass (μg) of monomethylhydrazine contained in the sample from the standard curve after subtracting the average absorbance of the control test tube. A6 Calculation
See formula (Ai).
Where: c——monomethylhydrazine concentration in air, mg/m2; m-·mass of monomethylhydrazine contained in the measured sample·ug; V. ——sample volume under standard conditions, L. A7 Explanation
(Al)
A7.1 The minimum detection concentration of this method is 0.0031mg/m (sampling volume 100L). The determination range is 0.010~2.5mg/m2. The average coefficient of variation in this range is 3.6%, and the average relative error is 5.5%. A7.2 Ammonia, nitrogen dioxide, sulfur dioxide, and unsymmetrical dimethylhydrazine in the air do not interfere with the determination of monomethylhydrazine. The oxidation products of unsymmetrical dimethylhydrazine show positive interference, and hydrazine seriously interferes with the determination of monomethylhydrazine. A7.3 The ambient temperature has an effect on the color development and color stability time. The absorbance of the sample decreases with the increase of ambient temperature. Therefore, the standard curve should be calibrated while measuring the sample, and the color development time should be controlled according to the room temperature of the day, see Table A1. Table A1
Centerology, C
Color development time, min
20～50
15~~35
B1 Principle
GB18058—2000
Appendix B
(Appendix of the standard)
Gas chromatography
Use a solid adsorbent coated with sulfuric acid to collect monomethylhydrazine in the air, desorb with sodium hydroxide solution, derivatize with 2,4-pentanedione, extract with ethyl acetate, separate with OV-17/Supelcoport column, detect with hydrogen flame ionization detector, qualitatively analyze with retention time, quantitatively analyze with peak height. B2 Apparatus
B2.1 The air sampler and sampling tube are the same as those in Appendix A, but the 6201 carrier is used instead of the 101 white carrier, and the tube is filled with 200 mg of treated carrier.
B2.2 stoppered graduated test tubes: 5 ml.
B2.3 Microsyringe: 10μL, 50μL. B2.4 Gas chromatograph, hydrogen flame ionization detector Chromatographic column: 3m long, 4mm inner diameter, stainless steel column. 15% 0V-17/Supelcoport80-100 mesh filling. Column temperature: 124C~134C;
Vaporization chamber temperature: 264C;
Detection chamber temperature: 264C;
Carrier gas: high-purity nitrogen, 70mL/min.
B3 Reagents
2,4-pentanedione: analytical grade,
Ethyl acetate: analytical grade.
Sodium hydroxide: analytical grade.
6201 carrier: 40~60 mesh.
Supelcoport carrier: 80~100 days. B3.5S
B3.6（)V-17: Chromatographic stationary phase.
Sulfuric acid, anhydrous ethanol, monomethylhydrazine, 6mol/L sulfuric acid solution, sulfuric acid ethanol solution: Same as Appendix A. B3.7
B3.8: Propellant grade product with purity above 98.5%. B3.9
Sulfuric acid solution: 0.4mol/L.
Sodium hydroxide solution: Weigh 6.7329g of sodium hydroxide into a volumetric flask containing 300ml of distilled water, cool to room temperature and dilute to 500ml with distilled water.
4 Sampling
The sampling operation steps and requirements are the same as Appendix A. B5 Analysis steps
B5.1 Control test: Same as Appendix A.
B5.2 Sample treatment: Transfer the sampled support into a stoppered graduated test tube, add 2mL sodium hydroxide solution for desorption, then add 20μg hydrazine and 2ul.2,4-pentanone, adjust the pH to 9.0, react at room temperature for 60min, and extract with 0.5ml ethyl acetate for 30min. The control test support 30
was also treated in the same way.
GB18058—2000
B5.3 Drawing of standard curve: Prepare standard stock solution as in Appendix A3.11. Add 200mg treated 6201 support, 2ml sodium hydroxide solution, 200ug hydrazine, and then add 5, 10, 15, 20, 25μl of methyl hydrazine standard stock solution in 5 stoppered graduated test tubes, and then add 2μl 2,4-pentanedione. After shaking, adjust the pH to 9, react at room temperature for 60min, extract with ethyl acetate for 30min, take 10μl of the extract and inject, repeat 3 times for each concentration. Qualitative analysis is performed by retention time, and the average peak height is plotted against the monomethyl hydrazine content to draw a standard curve, as shown in Figure B1.
B5.4 Determination: According to the conditions for drawing the standard curve, take 10μL of sample extract and inject it, repeat 3 times, subtract the peak height of the control test from the average peak height, and obtain the mass (μg) of monomethylhydrazine contained in the sample solution from the standard curve. 8
Figure B1 Chromatogram of methylhydrazine
B6 Calculation
Calculate according to formula (A1).
B7 Explanation
B7.1 The minimum detection concentration of this method is 0.0042mg/m2 (sampling volume 100L), the determination range is 0.01mg/m~~2.5mg/m, and the average coefficient of variation of the method is 2.6%. B7.2 Adding 200μg hydrazine or 140μg unsymmetrical dimethylhydrazine can eliminate the interference of hydrazine and unsymmetrical dimethylhydrazine and improve the sensitivity of the method. 51
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