Some standard content:
National Standard of the People's Republic of China
Health standard for ethylamine in the air of workplace
Health standard for ethylamine in the air of workplace Subject content and scope of application
This standard specifies the maximum allowable concentration of ethylamine in the air of workplace and its monitoring and inspection methods. This standard applies to all types of enterprises that produce and use ethylamine. 2 Hygiene requirements
The maximum allowable concentration of ethylamine in the air of workplace is 18mg/m. 3 Monitoring and inspection methods
The monitoring and inspection methods of this standard adopt gas chromatography and diazonium salt colorimetry. See Appendix A and B (supplement).
GB 16214—1996 approved by the State Administration of Technical Supervision on April 3, 1996
Implementation on September 1, 1996Www.bzxZ.net
A1 Principle
GB 16214—1996
Appendix A
Gas chromatography
(Supplement)
Collect ethylamine in the air in a silicone tube, desorb with dilute sulfuric acid, separate with polyethylene glycol 20M and potassium hydroxide columns, 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. A2 Instruments
A2.1 Silica gel sampling tube: 10 cm long, 4 cm inner diameter, containing two sections of silica gel, 200 mg in the front section and 100 mg in the rear section, separated by glass wool in the middle, fixed at both ends with glass wool, and sealed at both ends of the glass tube with fire. A2.2 Atmospheric sampler.
A2.3 Micro syringe, 100μl.
A2.4 Electric oscillator.
A2.5 Gas chromatograph, hydrogen flame ionization detector, chromatographic conditions
Chromatographic column: column length 3m, inner diameter 3mm, glass column. Polyethylene glycol 20M: potassium hydroxide: Chromosorb103 (60-80 days) = 2:1:100, column temperature: 125℃. b.
Vaporization chamber temperature: 200℃.
Detection chamber temperature: 200℃.
Carrier gas (nitrogen): 40mL/min.
A3 Reagents
A3.1 Anhydrous ethylamine, 99%, analytical grade.
A3.2 Silica gel: crush and sieve the original silica gel, select 20-40 mesh silica gel, wash it several times with deionized water, pour out the washing liquid, dry it at 110℃, and activate it at 340C for 3h.
A3.3 Polyethylene glycol 20M, chromatographic stationary liquid. A3.4 Chromosorb 103, 60-80 months. A3.5 Deionized water or double distilled water.
A3.6 0.1mol/L sulfuric acid solution.
A3.7 0.25mol/L sodium hydroxide solution.
A4 Sampling
Remove the seals at both ends of the silica gel sampling tube at the sampling site, place it vertically, collect 30L of on-site air at a rate of 500mL/min, put on the rubber cap, and bring it back to the laboratory for analysis.
A5 Analysis steps
A5.1 Control test
At the sampling site, use the silica gel sampling tube as the sample, but do not evacuate the air. A5.2 Sample treatment
Pour the two silica gel sections before and after the sampling tube into 10mlL stoppered colorimetric tubes, add 1.0mL 0.1mol/L sulfuric acid to each, plug tightly, and shake with an oscillator at 170
for 60min.
A5.3 Plotting the standard curve
GB 16214---1996
In a 10mL volumetric flask, add a small amount of 0.1mol/1. sulfuric acid, weigh accurately, then drop an appropriate amount of anhydrous ethylamine, and weigh again to make a stock solution of concentration. Before use, take a certain amount of stock solution, dilute it with 0.1mol/L sulfuric acid and 0.25mol/L sodium hydroxide to 0.0, 130.0, 260.0, 650.0 and 1300.0μg/mL ethylamine standard application solution, take 4μL of each sample, measure the retention time and peak height, repeat 3 times for each concentration, take the average of the peak height, plot the ethylamine content against the peak height, draw a standard curve, and use the retention time as a qualitative indicator. A5.4 Determination
Take 0.1ml of the sample solution. Add 0.25mol/L sodium hydroxide 0.1ml and shake well, then take 4μL of the sample immediately, and use the retention time for qualitative analysis and the peak height for quantitative analysis.
A6 Calculation
2(Ci+C2)
Where: X is the concentration of ethylamine in the air, mg/m\; X1000
（).C2—is the content of ethylamine in the desorbed sample solution of the front and rear sections of the silica gel, ug, an injection volume, pμL;
V. —converted to the sampling volume under standard conditions, L. A7 Notes
A7.1 The detection limit of this method is 0.01ug (injection of 4uL sample solution). A7.2 The average penetration capacity of the silicone tube is 3.7mg/100mg, the sampling efficiency is 99.5%, and the elution efficiency is 98.0%. (A1)
A7.3 When the concentration of dimethylamine is 450 times greater than the concentration of ethylamine, the two cannot be separated, and nitrogen, methylamine, ethanol, diethylamine, triethylamine, etc. have no interference with the determination.
A7.4 After sampling with the silicone tube, it can be placed at room temperature for 15 days. Appendix B
Diazonium colorimetric method
(Supplement)
B1 Principle
In a pH 8.5~9.0 buffer solution, the product of the combination of ethylamine and p-nitroaniline diazonium salt appears red, and the depth of the solution color is proportional to the ethylamine concentration within a certain range. B2 Instruments
B2.1 Large bubble absorption tube.
B2.2 Atmospheric sampler.
B2.3 Stoppered colorimetric tube, 10mL.
B2.4 Spectrophotometer.
B3 Reagents
Absorption solution: 0.04mol/L hydrochloric acid solution.
B3.25g/l. Sodium nitrite solution.
GB 16214—1996
B3.3 1g/l. p-nitroaniline hydrochloric acid solution: dissolve 0.1g p-nitroaniline in 100mL 1.0mol/L hydrochloric acid solution. B3.4 200g/l sodium hydroxide solution.
B3.5 p-nitroaniline diazonium salt solution: add 1.0mL sodium nitrite solution pre-cooled to (～5) to 10ml p-nitroaniline hydrochloric acid solution pre-cooled to 05C, mix well. Store in a cool place and prepare before use. B3.6 Buffer solution: dissolve 4.08g potassium dihydrogen phosphate and 1.9g borax in 80mL distilled water, adjust pH to 8.5～9.0 (measured by acidometer) with hydrochloric acid, and then dilute to 100mL with water. B3.7 Ethylamine standard Standard solution: Add 99% anhydrous ethylamine solution drop by drop into a weighing bottle that has been weighed and filled with 0.04mol/L hydrochloric acid solution to prepare a concentrated ethylamine standard solution. Take this concentrated standard solution and dilute it with 0.04mol/L hydrochloric acid solution to a standard application solution containing 10.0μg/mL ethylamine. B4 Sampling
Connect two large bubble absorption tubes, each containing 10.0mL absorption liquid, in series, and collect 2.5L of air sample at a speed of 0.5L/min. B5 Analysis steps|| tt||B5.1 Control test: Connect two large bubble absorption tubes containing 10.0 ml absorption liquid in series, take them to the sampling site, and perform the same operation, but do not draw air samples.
B5.2 Sample treatment: Take 1.0 ml of sample liquid from each of the front and rear tubes, add 4.0 ml of buffer respectively, and the following steps are the same as for the standard tube. B5.3 Preparation of standard curve: Prepare standard tubes according to Table B1. Table B1 Preparation of ethylamine standard tubes
Standard solution, ml.| |tt||Absorption liquid,
Ethylamine content,
Add 4.0mL buffer and 0.5mL diazonium salt solution to each tube at the same time, shake and mix, place for 30 minutes, add 1.0mL 200g/L sodium hydroxide solution, mix, place for 10 minutes, compare color at 510nm, plot the ethylamine content against the absorbance, and draw a standard curve. B5.4 Determination: Determine the treated sample in the same way as the standard tube. B6 Calculate
_10(Cr +C,)
Where: X is the concentration of ethylamine in the air, mg/m; (1, C2—the content of ethylamine in the sample liquid taken from the front and rear sampling tubes, ug; V,——the sampling volume converted to standard conditions, L. B7 Notes
B7.1 The detection limit of this method is 0.37ug/mL. (B1)
B7.2 When the ethylamine content is 3.0μg, 40μg ammonia and 60μg diethylamine have no interference with the determination, but aliphatic primary amines have interference with the determination. B7.3 The pH value of the buffer and the amount of diazonium salt added must be strictly controlled, as they have a great influence on the color development reaction. Additional Notes:
This standard was proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Sichuan Provincial Institute of Labor Hygiene and Occupational Disease Prevention and Control. The main drafters of this standard are Wang Dingguo, Liu Liping, Yu Ying, and Zheng Hua. This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine, the technical unit entrusted by the Ministry of Health. 172
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