This standard specifies the maximum permissible concentration of trifluoromethyl hypofluorite in workshop air and its monitoring and inspection methods. This standard is applicable to all types of workplaces where trifluoromethyl hypofluorite is produced and used. GB 16191-1996 Hygienic Standard for Trifluoromethyl Hypofluorite in Workshop Air GB16191-1996 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Health standard for trifluoromethylhypofluorite in the air of workplaceHealth standard for trifluoromethylhypofluorite in the air of workplace1 Subject content and scope of application
GB16191-1996
This standard specifies the maximum allowable concentration of trifluoromethylhypofluorite in the air of workplace and its monitoring and inspection methods. This standard applies to all types of workplaces where trifluoromethylhypofluorite is produced and used. 2 Hygiene requirements
The maximum allowable concentration of trifluoromethylhypofluorite in the air of workplace is 0.2mg/m3. 3 Monitoring and inspection methods
The monitoring and inspection methods of this standard adopt the stationary phase freeze concentration-gas chromatography method, see Appendix A. Monitoring implementation
Health administrative departments at all levels are responsible for supervising the implementation of this standard. Approved by the State Administration of Technical Supervision on April 3, 1996 406
Implemented on September 1, 1996
A1 Principle
GB16191—1996
Appendix A
Stationary phase freeze concentration-gas chromatography
(Supplement)
Trifluoromethyl hypofluorite in air is freeze concentrated with perfluoroether oil-silica gel chromatography stationary phase, separated by the column after thermal desorption, detected by electron capture detector, qualitative by retention time, quantitative by peak area. The detection limit of this method is 6×10-3mg/m2.
A2 Instruments
A2.1 Gas chromatograph, electron capture detector. A2.2 Super thermostat.
A2.3 Wide-mouth thermos bottle.
A2.4 10L polyvinyl chloride film (0.2mm) sampling bag. A2.5 Concentrator: stainless steel spiral tube, 1m long, 4mm inner diameter. A2.6 Syringes: 100mL, 2mL, 100μL. A3 Reagents
A3.1 Trifluoromethyl hypofluorite standard gas (purity>98%). A3.2 Perfluoroether oil, chromatographic stationary liquid.
A3.3 Chromatographic silica gel, 60-80 mesh.
A3.4 Liquid nitrogen.
A3.5 Alcohol. www.bzxz.net
A4 Sampling
Use a purified sampling bag connected to a two-way three-way piston and a 100mL syringe, and use a 100mL syringe to measure and extract samples from the on-site air and store them in an air bag for later use.
A5 Analysis steps
A5.1 Freeze concentration method
A5.1.1 Place the concentrator tube in a 116℃ cold trap for precooling for 25 minutes, then connect a nitrogen bag to the injection end of the tube, turn on the water pump and adjust to the required flow rate. After 5 minutes, replace the sample bag at the injection end to control a certain flow rate for sample concentration. A5.1.2 After concentrating to a certain volume, close the injection end and the sample bag outlet, remove the sample bag, and continue to pump for 2 minutes to reduce residual oxygen. Close the suction end of the concentrator tube, remove the concentrator tube, and connect a 100mL syringe at the suction end to collect the concentrated sample. A5.1.3 After the concentration tube has heated up naturally for 10 minutes, place the tube in a 40℃ constant temperature water bath. After thermal desorption for 40 minutes, use a 100mL syringe to add 80mL of nitrogen gas evenly at the injection end of the tube within 8 minutes. Replace all the samples in the concentration tube into the sample collector, immediately clamp the rubber tube on the collector, remove the collector, accurately record the volume of concentrated gas collected, mix well and perform chromatographic analysis. A5.2 Chromatographic conditions
a. Chromatographic column: 10% perfluoroether oil-silica gel, 375mm×4mm (inner diameter) stainless steel tube. The freezing concentration and pyrolysis absorption device is shown in Figure A1. 407
Water pump
GB16191—1996
a. Sample freezing concentration device
1 Spiral water stop clamp (the rest are spring water stop clamps); 2—3I. Safety bottle; 3, 5—gas-water separator; 4—soap film flow meter; 6—stationary phase sample concentration tube; 7 Wide-mouth thermos bottle 8-stirring rod: 9--thermometer: 10—sample bag Column temperature: 40℃.
Vaporization chamber temperature: 60℃.
Detection chamber temperature: 240℃.
Detector: ECD3Ni, pulse period, 100μs, amplifier input high impedance, 10°α. b. Pyrolysis absorption collection device
1-Super thermostat; 2-Sample concentrator; 3-Sample collector: 4-Spring water stop clamp Carrier gas: Nitrogen, 15mL/min (purified by activated carbon, 5A molecular sieve dehydration silica gel). A5.3 Preparation of standard samples
After evacuating a 100mL syringe to vacuum, seal the air inlet, inject 20mL of nitrogen, accurately extract a certain amount of trifluoromethyl hypofluorite pure gas with a micro syringe, inject it into the syringe, and then dilute it with nitrogen to 100mL scale, mix it as a standby standard gas, and then dilute it with nitrogen to prepare the required standard gas samples of various concentrations. Measure the retention time and peak area, and draw a standard curve. A5.4 Chromatogram
Figure A2 Sample separation diagram
Time, min
1—Air; 2—CF4; 3—CF:OF; 4--COz; 5—CF,OOCFs408
A5.5 Sample analysis
GB 16191—1996
Figure A3 Concentrated sample analysis diagram
1(;2 --CF,(F;3 CO2
Time. min
Use the same analytical conditions as the standard sample to analyze the concentrated sample, use retention time for qualitative analysis, and peak area and recovery concentration multiple for quantitative analysis. A6 Calculation
Where:
A·T,·R
Concentration of trifluoromethyl hypofluorite in air, mg/m3; Peak area of ​​concentrated sample, cm2;
Standard concentration of C-trifluoromethyl hypofluorite, mg/m3; A.
Peak area of ​​a standard, c m\;
Volume concentration multiple,
R-recovery rate.
Zhongye Electric Power
Note: After use, the concentrator tube should be checked and treated with nitrogen in a 40℃ water bath, and then checked again for the next concentration. Additional Note:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard is drafted by the Sichuan Provincial Institute of Labor Hygiene and Occupational Disease Prevention and Control. The main drafters of this standard are Wang Zefu, Kang Zhongyu, Ding Shouxian, Zhang Wanyou, and Xiang Weijun. ++..-.(Al )
This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases, Chinese Academy of Preventive Medicine, which is the technical management unit entrusted by the Ministry of Health. 109
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