GB 16223-1996 Hygienic standard for unsymmetrical dimethylhydrazine in workshop air
Some standard content:
National Standard of the People's Republic of China
Health standard for unsymmetricdinethylhydrazine in the air of workplace Subject content and scope of application
This standard specifies the maximum permissible concentration of unsymmetricdinethylhydrazine in the air of workplace and the monitoring and inspection methods. This standard applies to all types of enterprises that produce and use unsymmetricdinethylhydrazine. Hygienic requirements
The maximum permissible concentration of unsymmetricdinethylhydrazine in the air of workplace is 0.5mg/m3 (skin). 3 Monitoring and inspection methods
For the monitoring and inspection methods of this standard, see Appendix A (supplement) and Appendix B (supplement). GB16223-1996 approved by the State Administration of Technical Supervision on April 3, 1996
Implementation on September 1, 1996
A1 Principle
GB 16223—1996
Appendix A
Sodium amino ferrocyanide colorimetric method
(Supplement)
Use a solid adsorbent coated with sulfuric acid to collect unsymmetrical dimethylhydrazine in the air, desorb it and react with sodium amino ferrocyanide under weak acidic conditions to generate a red complex, and perform colorimetric quantification.
A2 InstrumentsbzxZ.net
A2.1 Cold graduated test tube, 25ml.
A2.2 Graduated pipette, 10, 5, 2, 1ml.
A2.3 Micro syringe, 50, 10zl.
A2.4 Spectrophotometer.
A2.5 Acidity meter.
A2.6 Air sampler, 0～2L/min.
A2.7 Sampling tube, made according to the following procedure: weigh 10.0g 6201 support, boil in 100mL distilled water for 3min, rinse with distilled water 5 times, 100mL of water each time, visually check that the clarity of the upper clear liquid is consistent with that of distilled water, take the upper clear liquid and use distilled water as blank, measure the absorbance at 500nm with 2cm colorimetric III, and it is qualified if it is not greater than 0.02. Drain the washed support with a Buchner funnel, transfer to the surface blood, dry at 70℃ for 40min, move to a dryer, and cool to room temperature. Weigh 4.0g of the clean support and spread it on surface III, add 11.0mL of sulfuric acid-acetic acid solution to make it evenly soaked, place it in a fume hood to air dry, and then dry it at 80±1℃ for 40min until it is loose and not lumpy, cool it to room temperature in a desiccator, and bottle it for later use. Weigh 300mg of the sulfuric acid-coated support and put it into a glass tube (90mm long, 6mm inner diameter), fix the two ends of the support with a clean stainless steel mesh (60 mesh), and seal the two ends of the tube with a polyethylene cap. A3 Reagents
A3.1 Sulfuric acid, high-grade pure.
A3.2 Anhydrous ethanol, high-grade pure.
A3.3 Anhydrous ethanol, analytical grade.
A3.4 Ether, analytical grade.
A3.5 Concentrated ammonia water, analytical grade.
A3.6 Citric acid (C, HO, ·H, O), analytical grade. A3.7 Disodium hydrogen phosphate (NazHPO, ·12H,O), analytical grade. A3.8 Sodium nitrosoferrocyanide.
A3.96201 Support, 40-60 mesh.
Sulfuric acid solution, 6mol/L, c(H,SO).
A3.11 Citric acid solution, 0.1mol/Lc(CHO,). Disodium hydrogen phosphate aqueous solution, o.2mol/L, c(NazHPO). A3.12
A3.13 Sulfuric acid-ethanol solution, add 36mL of sulfuric acid solution (A3.10) to 200mL of anhydrous ethanol (A3.2), and dilute to 250mL with anhydrous ethanol (A3.2).
A3.14 Buffer solution, use citric acid solution and disodium hydrogen phosphate solution to prepare buffer solutions of pH=5.4 and pH=6.2 in proportion, see Table Al:
Solution pH value
GB16223—1996
0.1mol/1.Citric acid, ml,
0.2mol/L Disodium hydrogen phosphate, ml
A3.15 Preparation of sodium aminoferrocyanide: Weigh 10.0g of sodium nitrosoferricyanide, grind it into a conical flask, add 32ml of concentrated ammonia water, shake well and cover it, let it stand at 0℃ for 12h, add 20mL of anhydrous ethanol (A3.3) to obtain a yellow precipitate, filter it with a Buchner funnel, first rinse it three times with 60mL of anhydrous ethanol (A3.3) and then with 60mL of ether, and drain it. Move the yellow solid to the surface blood, place it in a desiccator for more than 2 hours, then transfer it to a brown narrow-necked bottle and store it in a dark place. A3.16 0.2% amino ferrocyanide sodium color developer: weigh 0.10g amino ferrocyanide sodium powder and dissolve it in 25ml. distilled water, transfer it to a 50ml brown container, dilute it to the scale with distilled water, and shake it well. Prepare it on the day of the test. A3.17 Standard solution: In a 100mL volumetric flask, add 50mL of pH=5.4 buffer solution and 5ml of 6mol/L sulfuric acid, and shake it well. Use a syringe to weigh 0.127mL (accurate to 0.0001g) of unsymmetrical dimethylhydrazine by reduction method, and inject it into the above volumetric flask. When weighing, use a small rubber piece to seal the needle tip to prevent unsymmetrical dimethylhydrazine from leaking. Gently shake the volumetric flask to dissolve the unsymmetrical dimethylhydrazine. After 20 minutes, dilute it to the scale with pH5.4 buffer solution. Shake well to obtain a 1.0mg/mL standard solution, which can be stored for two weeks at room temperature. A4 Sampling
Open the sampling tube at the sampling site, connect one end to the air sampler, place the sampling tube vertically with the tube mouth facing downward, and collect air at a rate of 2L/min for 30~1001. After sampling, seal both ends with polyethylene caps, put in a plastic bag, and send 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 then seal it with polyethylene caps and keep it for control test.
A5.2 Sample treatment: Transfer the carriers of the sampled and control test sampling tubes into stoppered graduated test tubes respectively, rinse the sampling tube wall with 20ml of pH=6.2 buffer solution for 3~4 times, let it stand for 20min, add 1mL of nitrogen-based sodium ferrocyanide color developer, dilute to the scale with pH=6.2 buffer solution, invert 5 times, and color in the dark for 50min (20℃). A5.3 Drawing of standard curve: Take 11 test tubes with stoppers and add 15 ml of pH-6.2 buffer solution and 300 mg of sulfuric acid-coated support to each tube. Use 3 tubes as blanks and add 5, 10, 15, 20, 25, 30, 35, and 40 μl of unsymmetrical dimethylhydrazine standard solution to the remaining 8 tubes. Then add 1 ml of amino ferrocyanide sodium colorimetric reagent to each of the 11 test tubes and dilute to the scale with pH-6.2 buffer solution. Invert each tube 5 times and place in the dark to develop color for 50 minutes (20°C). Use distilled water as a reference and 2 cm colorimetric blood to measure the absorbance of the supernatant at 500 nm. Subtract the average absorbance of the blank to obtain the net absorbance value of each solution. Draw the unsymmetrical dimethylhydrazine content (rg)-absorbance curve. A5.4 Determination: Determine the absorbance of the sample according to the conditions and steps for making the standard curve, and after subtracting the average absorbance of the control test tube, obtain the unsymmetrical dimethylhydrazine content (μg) from the standard curve. A6 Calculation
Calculate the unsymmetrical dimethylhydrazine concentration in the air according to the following formula: (Al)
Where: X--unsymmetrical dimethylhydrazine concentration in the air, mg/m\(--measured unsymmetrical dimethyl content, g,
V. Sample volume under standard conditions, L.
A7 Explanation
GB 16223—1996
A7.1 The minimum detection concentration of this method is 0.015mg/m3 (sampling volume 120L). The measurement range is 0.027~5.46mg/m2. When the concentration of unsymmetrical dimethyl hydrazine is lower than 0.134mg/m3, the coefficient of variation is less than or equal to 16%. When the concentration is 0.134~～5.46mg/m2, the coefficient of variation is less than or equal to 5.0%.
A7.2 Ammonia, nitrogen dioxide, sulfur dioxide, hydrogen sulfide and nitrogen in the air do not interfere with the determination of unsymmetrical dimethyl hydrazine. When the concentration of unsymmetrical dimethyl hydrazine is lower than 0.3mg/m2 and the concentration of methyl hydrazine is lower than 0.5mg/m3, there is no interference with the determination of unsymmetrical dimethyl hydrazine. A7.3 Each batch of carriers is The pH value should be adjusted in advance to ensure that the pH of the solution being tested is 5.4±0.2. A7.4 The ambient temperature affects the color development time and color stability. The color development time can be selected according to Table A2. Table A2
Color development time.min
B1 Principle
Appendix B
Gas chromatography
(Supplement)
Use a solid adsorbent coated with sulfuric acid to collect unsymmetrical dimethylhydrazine in the air. After water desorption, furfural derivatization, and ethyl acetate extraction, separate on an (OV-7/Supelcoport column and detect with a hydrogen flame ionization detector. The retention time is used for qualitative analysis and the peak height is used for quantitative analysis. B2 Instrument
B2.1 Air sampler and sampling tube are the same as Appendix A (supplement). The tube contains 200 mg of carrier. B2.2 Stoppered graduated test tube, 5 mL.
B2.3 Micro syringe, 50, 10 μL.
B2.4 Gas chromatograph, hydrogen flame ionization detector. Chromatographic column: 3m long, 4mm inner diameter, glass column: 10% (V-7/Supelcoport80~100 filling; Guizhuyuan: 205C;
vaporization chamber temperature: 315℃;
detection chamber temperature: 315C;
carrier gas: high-purity nitrogen, 50mL/min.
B3 reagents
B3.1 furfural, analytical grade.
B3.2 ethyl acetate, analytical grade.
B3.3 sodium acetate, analytical grade.
B3.4 sulfuric acid solution, 0.5mol/L, c(H,SC),). B3.5 sodium acetate solution, 0.5mol/L, c(CH.COONa). 508
GB16223--1996
B3.6 Furfural derivatization reagent: Pipette 2mL of freshly distilled furfural into a 50mL volumetric flask and dilute to scale with sodium acetate solution. B3.7 Sulfuric acid, ethanol, 6201 support, unsymmetrical dimethylhydrazine, sulfuric acid-ethanol solution, 6mol/L sulfuric acid solution are the same as Appendix A (Supplement). B3.8 (V-7, chromatographic stationary liquid.
B3.9 Supelcoport support, 80-100 mesh. B4 Sampling
The sampling operation steps and requirements are the same as Appendix A (Supplement). B5 Analysis steps
B5.1 Control test: Same as Appendix A (Supplement). 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, then add 2mL of furfural derivatization reagent, react at room temperature for 60min, and extract with 1mL of ethyl acetate for 20min. w9z,
Figure B1 under selected conditions Chromatographic peak diagram
B5.3 Drawing of standard curve: Prepare standard solution as in A3.17 of Appendix A (Supplement), take 2, 4, 8, 12, 16, 20μl of unsymmetrical dimethylhydrazine standard solution (1.0μg/μl.), add them to 6 stoppered graduated test tubes respectively, then add 0.20g of solid adsorbent, 2mL of distilled water, and 2mL of furfural derivatization reagent to each tube, react at room temperature for 60min, extract with 1mL of ethyl acetate for 20min, take 10μL of extract for injection, repeat three times for each concentration, plot the sample content with the average peak height, draw the standard curve, and use the retention time as the qualitative indicator. 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 UDMH content (μug) from the standard curve. B6 Calculation
Where: X--the concentration of UDMH in the air, mg/m3; (the measured UDMH content, u8
(B1)
V. The sample volume under the standard push condition,
87 Note
GB16223-1996
B7.1 The minimum detection concentration of this method is 0.0218mg/m3 (sampling volume 120L), and the measured The determination range is 0.026~6.7mg/m2, and the average relative error of the method is 9.3%.
B7.2 The chromatographic conditions of this method can monitor hydrazine simultaneously. Additional notes:
This standard is 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 participated in 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. 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, is responsible for the interpretation of this standard. 510
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