This standard specifies the maximum permissible concentration of furan in workshop air and its monitoring and testing methods. This standard is applicable to all types of enterprises that produce and use furan. GB 16235-1996 Hygienic Standard for Furan in Workshop Air GB16235-1996 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Health standard for furan in the air of workplace
Health standard for furan in the air of workplace Subject content and scope of application
This standard specifies the maximum allowable concentration of furan in workplace air and its monitoring and inspection methods. This standard applies to all types of enterprises that produce and use furan. 2 Hygiene requirements
The maximum allowable concentration of furan in workplace air is 0.5mg/m3. 3 Monitoring and inspection methods
The monitoring and inspection methods of this standard adopt gas chromatography, see Appendix A (supplement). GB 16235-1996 approved by the State Administration of Technical Supervision on April 3, 1996. Implementation on September 1, 1996. A1 Principle GB 16235-1996 Appendix A Gas Chromatography (Supplement) A1.1 Collect furan in the air with an activated carbon tube, heat and desorb it in a thermal desorber, separate it with an FFAP column, and detect it with a hydrogen flame ionization detector. The retention time is used for qualitative analysis and the peak height is used for quantitative analysis. A1.2 The detection limit of this method is 1.0×10-6μg (direct injection of 1mL air sample). A2 Instruments
A2.1 Activated carbon tube: Use a glass tube with a length of 250mm, an inner diameter of 3.4-4mm, and an outer diameter of 6mm, and load it with 100mg (20-40 mesh) coconut shell activated carbon. Fix the two ends with a small amount of glass wool. Before loading the tube, the activated carbon should be aged at 300-350℃ while passing nitrogen for 3-4h. After loading the tube, put it in the thermal desorption instrument and blow nitrogen at 350℃ for 5-10min. When used in a short time, put plastic caps on both ends for storage. A2.21150mL saline bottle, 100mL, 1mL, 10μL syringe. A2.3 Thermal desorption instrument, thermal desorption temperature: 250C. A2.4 Gas chromatograph, hydrogen flame ionization detector. A2.5 Chromatographic conditions:
Chromatographic column: 2m long, 4mm inner diameter, stainless steel column; FFAP: Chromosorb WHP10:100; Column temperature: 55℃C. at
Vaporization temperature: 150℃.
Detection chamber temperature: 150℃.
Carrier gas (Nz): 30mL/min.
A3 Reagents
A3.1 Furan (chromatographic grade).
A3.2 Stationary liquid: FFAP.
A3.3 Support: Chromosorb WHP (100~12o). A4 Sampling
Open the activated carbon tube at the sampling site and place it vertically, and extract 5L of air at a rate of 0.5L/min. After sampling, put plastic caps on both ends of the tube and bring it back to the laboratory for analysis.
A5 Analysis steps
A5.1 Control test: Treat the activated carbon that has not been sampled in the same way as the sample as a blank control. A5.2 Drawing of the standard curve: First prepare 16μL furan/1mL CS standard solution (at 20℃, the mass of 1μL furan is 0.9514μg). Use a micro syringe to take a certain amount of the above solution and inject it into a 1150mL saline bottle, dilute it with clean air, and then use a 100mL syringe to prepare furan standard gas with concentrations of 0.25, 0.50, and 2.5ng/mL. Take 1mL of sample for analysis respectively. Measure the retention time and peak height. Repeat 3 times for each concentration. Take the average value of the peak height. Use peak height to draw a standard curve against content. Qualitative analysis by retention time. A5.3 Sample analysis: Remove the plastic caps at both ends of the sample tube, place it in the heating part of the thermal desorption instrument, heat it at 250℃ while passing nitrogen (1ml./s), and carry it into the chromatograph for analysis by nitrogen. The retention time is used for qualitative analysis and the peak height is used for quantitative analysis. 544bZxz.net
A6 Calculation
Wherein, X is the concentration of furan in the air, mg/m3; GB16235-1996
(——the furan content in the desorbed gas found on the standard curve, ug, V
the sample volume under standard conditions, L.
A7 Notes
(A1)
A7.1 When the concentration of furan standard gas is 0.25, 0.50, and 2.5 ng/mL, the relative standard deviation of direct injection of 1 mL of standard gas is 1.6%, 1.4%, and 1.2%, and the relative standard deviation of standard gas after desorption by activated carbon is 5.8%, 4.2%, and 1.2%. A7.2 When the furan concentration in the air is 30 mg/m3 and the relative humidity is 88%, 0.5 L of air is collected and the sampling efficiency is 99.8% on average. A7.3 Store at room temperature for 1 week , the furan concentration adsorbed in the activated carbon decreased and changed little. A7.4 When the desorption temperature is 200℃, the furan desorption efficiency reaches 99.5%, so the desorption temperature is selected to be 250℃. A7.5 Methanol, ethanol, propanol, isopropanol and n-butanol that may coexist in the on-site air have no interference with the determination. A7.6 When the air humidity is 89%, the sampling rate is 0.1L/min, and the penetration capacity of furan is 2.64mg. a
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Chromatogram
Additional notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Institute of Occupational Disease Prevention and Control of Zhejiang Academy of Medical Sciences. The main drafters of this standard are Yu Yongdan, Chen Xiufeng and Ni Bo. 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. 545
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