Some standard content:
National Standard of the People's Republic of China
Health standard for hydrazine in the air of workplace
Subject content and scope of application
This standard specifies the maximum permissible concentration of hydrazine in the air of workplace and the monitoring and inspection methods. This standard applies to all types of enterprises that produce and use hydrazine. 2 Hygienic requirements
The maximum permissible concentration of hydrazine in the air of workplace is 0.13mg/m3 (skin). 3 Monitoring and inspection methods
For the monitoring and inspection methods of this standard, see Appendix A and B (supplement). Approved by the State Administration of Technical Supervision on April 3, 1996 4.94
GB 16221-1996
Implementation on September 1, 1996
A1 Principle
GB16221--1996
Appendix A
P-dimethylaminobenzaldehyde colorimetric method
(Supplement)
Use a solid adsorbent coated with sulfuric acid to collect hydrazine in the air, desorb it and react with p-dimethylaminobenzaldehyde to generate a yellow azine compound, and quantify it by colorimetry.
A2 Instruments
A2.1 Graduated test tube with stopper, 25mL.
A2.2 Graduated pipette, 10mL, 5mL.
A2.3 Spectrophotometer.
A2.4 Air sampler, 0~2L/min.
A2.5 Sampling tube, made according to the following procedure: weigh 10.0g 40~60 mesh 101 white carrier, boil in 100mL distilled water for 3min, pour out the upper turbid liquid, rinse repeatedly with distilled water until the rinse liquid is clear and transparent. Filter the carrier with a Buchner funnel until dry, then transfer it to surface III, spread it evenly, dry it at 70±1℃ for 40~50min, and transfer it to a dryer to cool. Weigh 4.0g of the washed carrier, spread it evenly on the surface blood, use a pipette to take 11.0mL of sulfuric acid-ethanol solution, evenly drip it on the carrier, air dry in a fume hood, move it into a constant temperature drying oven at 80±1℃, dry it for 40min (until the carrier is loose), transfer it to a dryer 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 tube (90 mm long, 6 mm inner diameter). Fix the two ends of the support with a clean 60-mesh stainless steel mesh. After installation, seal it with a polyethylene cap in time. A3 Reagents
A3.1 Sulfuric acid, high-grade purity.
A3.2 Anhydrous ethanol, high-grade purity.
A3.3 Ethanol, analytical grade.
A3.4 Hydrazine sulfate, analytical grade.
A3.5 p-Dimethylaminobenzaldehyde, analytical grade. A3.6101 White support, 40-60 mesh.
A3.7 Sulfuric acid solution, c(H2SO)=0.15mol/L. A3.8 Sulfuric acid solution, c(H,SO,)-6moi/L. A3.9 p-dimethylaminobenzaldehyde solution, weigh 10.0g p-dimethylaminobenzaldehyde, dissolve in 500mL ethanol, add 20ml 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 aqueous solution (A3.8) to 200ml anhydrous ethanol, and then dilute to 250ml with anhydrous ethanol. A3.11 Standard solution, weigh 0.4066g sulfuric acid and place it in a 1000mL volumetric flask, dissolve it with sulfuric acid solution (A3.7) and dilute to the scale and shake well. Take 5.0ml of this solution, put it in a 500ml volumetric flask, dilute to the scale with sulfuric acid solution (A3.7), and shake well. The concentration in this standard solution is 1.0μg/ml.
A4 Sampling
Remove the polyethylene caps at both ends of the 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 30~501 of air at a speed of 11/min. After sampling, seal both ends of the sampling tube with polyethylene caps, put it in a plastic bag, and send it to the laboratory for analysis. 493
A5 Analysis steps
GB 16221—1996
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 then seal it with polyethylene caps and keep it for control test.
A5.2 Sample treatment: Transfer the carriers of the sample tubes and the control test tubes into graduated test tubes respectively. Rinse the sampling tubes 4-5 times and the graduated test tube walls 3 times with a small amount of sulfuric acid solution (A3.7) to make the solution in the tube about 10mL. Shake intermittently to promote desorption. After 10 minutes, add 10mL of p-dimethylaminobenzaldehyde solution and dilute to the scale with sulfuric acid solution (A3.7). Shake and let stand for 30 minutes. A5.3 Drawing of standard curve: Take 7 stoppered graduated test tubes, add 300 mg of acid-coated support to each tube, use two tubes as blanks, and add 1.0, 2.0, 3.0, 4.0, 5.0 ml of 1.0 μg/mL hydrazine standard solution to the other 5 tubes, wash the tube mouths with sulfuric acid solution (A3.7) 3 times, then add 10 ml of p-dimethylaminobenzaldehyde solution to each tube, dilute to the scale with sulfuric acid solution (A3.7), shake well and let stand for 30 minutes, then use 2 cm colorimetric III, wavelength 460nm, adjust to zero with sulfuric acid solution (A3.7), measure the absorbance of the supernatant in each tube, subtract the average absorbance of the blank to obtain the net absorbance of each solution. Draw the hydrazine content (μg)-absorbance curve. A5.4 Determination: Determine the absorbance of the sample according to the conditions and steps for making the standard curve, and find the hydrazine content (μg) from the standard curve after subtracting the average absorbance of the control test tube.
A6 Calculation
Where: X-concentration of hydrazine in air, mg/m\; C---measured hydrazine content, ug;
V. —sample volume under standard conditions, L. A7 Explanation
(A1)
A7.1The minimum detection concentration of this method is 0.0012mg/m (sampling 60L), the determination range is 0.00714~1.00mg/m, and the average coefficient of variation within this range is 7.4%.
A7.2Ammonia, unsymmetrical dimethylhydrazine, nitrogen dioxide, sulfur dioxide, and hydrogen sulfide in the air do not interfere with the determination of hydrazine, but chlorine (negative), monomethylhydrazine (positive), and unsymmetrical dimethylhydrazine oxidation products have interference. Appendix B
Gas chromatography
(Supplement)
B1 Principle
Hydrazine in the air is collected using a solid adsorbent coated with sulfuric acid. After water desorption, furfural derivatization, and ethyl acetate extraction, it is separated by an OV-7/Supelcoport column and detected by a hydrogen flame ionization detector. The retention time is used for qualitative analysis and the peak height is used for quantitative analysis. B2 Instruments
B2.1 The air sampler and sampling tube are the same as those in Appendix A. However, a 6201 support is used instead of a 101 white support, and the tube is filled with 200 mg of the treated support.
B2.2 A stoppered graduated test tube, 5 mL.
B2.3 A microsyringe, 10 μl.
B2.4 Gas chromatograph, hydrogen flame ionization detector. GB16221—1996
Chromatographic column: 4m long, 3mm inner diameter, glass column, 10% 0V-7/Supelcoport80～100 mesh filling. Column temperature: 205℃.
Vaporization chamber temperature: 315℃.
Detection chamber temperature: 315℃.
Carrier gas: high-purity nitrogen, 50ml./min.
B3 Reagents
B3.1 Furfural, analytical grade, distilled before use. B3.2 Ethyl acetate, analytical grade.
B3.3 Sodium acetate, analytical grade.
B3.46201 Support, 40～60 mesh.
B3.5 Sodium acetate solution, c(CH;COONa)=0.5 mol/L. B3.6 Furfural derivative solution: Pipette 2mL of freshly distilled furfural into a 50mL volumetric flask, dilute to scale with sodium acetate solution, and shake well. B3.7 Hydrazine sulfate, sulfuric acid, anhydrous ethanol, 0.05mol/L sulfuric acid solution, 6mol/L sulfuric acid solution, and sulfuric acid ethanol solution are the same as Appendix A. B4 Sampling
The sampling operation steps and requirements are the same as Appendix A. B5 Analysis steps
B5.1 Control test: the same as Appendix A.
B5.2 Sample treatment
Transfer the support of the sample and control test sampling tubes into a stoppered graduated test tube, add 2mL of distilled water for desorption, and then add 2mL of furfural derivative solution, react at room temperature for 60min, and extract with 1mL of ethyl acetate for 20min. ,
Figure B1 Chromatographic peak diagram under selected conditions
B5.3 Drawing of standard curve: Prepare the standard solution of 497
GB16221—1996
200mg of treated 6021 support and 2ml of distilled water in 5 stoppered test tubes, and then add 0.1, 0.2, 0.3, 0.4, 0.5mL of standard solution of 1.0μg/mL), then add 2mL furfural derivative solution, react at room temperature for 60min, extract with 1mL ethyl acetate for 20min, take 10μL extract solution for injection, and repeat 3 times for each concentration. Qualitative analysis is performed by retention time, and the average peak height is plotted against the content to draw a standard curve. B5.4 Determination: According to the conditions for drawing the standard curve, take 10μL sample extract solution for injection, repeat 3 times, and subtract the control test peak height from the average peak height to obtain the hydrazine content (ug) from the standard curve. B6 Calculation
Where: X is the concentration of hydrazine in the air, mg/m~; the measured hydrazine content, ug;
V. —The sample volume under standard conditions, L. B7 ExplanationbzxZ.net
(B1)
B7.1 The minimum detection concentration of this method is 0.0072mg/m2 when sampling 60L. The determination range is 0.0072～1.00mg/m2. The average relative error of the method is 3.7%.
B7.2 The chromatographic conditions of this method can simultaneously monitor UDMH. B7.3 The collected samples can be stored in the dark at room temperature for one week, but samples mixed with UDMH should be analyzed on the day of sampling. Additional notes:
This standard was proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Seventh Design Institute of the Ministry of Aerospace Industry, and was jointly drafted by the Institute of Toxicology and Pharmacology of the Academy of Military Medical Sciences 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 interpreted by the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine, the technical management unit entrusted by the Ministry of Health. 498
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