This standard specifies the maximum permissible concentration of methyl mercaptan in the atmosphere of residential areas and its monitoring and inspection methods. This standard is applicable to the monitoring and evaluation of the atmospheric environment in residential areas. GB 18056-2000 Hygienic standard for methyl mercaptan in the atmosphere of residential areas GB18056-2000 Standard download decompression password: www.bzxz.net

GB18056—2000
All technical contents of this standard are mandatory. Fore
To implement the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on the Prevention and Control of Air Pollution, prevent and control the environmental pollution of residential areas caused by waste gas generated by industrial enterprises, and protect the health of the general public. This standard is formulated based on the principles of formulating health standards for harmful gases in the atmosphere, with reference to foreign research results, and based on the actual situation in my country. This standard shall be implemented from January 1, 2001. This standard is proposed by the Ministry of Health of the People's Republic of China, and Appendix A of this standard is the appendix of the standard.
Drafting unit of this standard: School of Public Health, Sun Yat-sen University of Medical Sciences. The main drafters of this standard: Chen Chengzhang, Song Hong, Zhong Saixian, Zhao Zhenxin. This standard is entrusted by the Ministry of Health to the Institute of Environmental Health Monitoring of the Chinese Academy of Preventive Medicine for interpretation. 41
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National Standard of the People's Republic of China
Hygienic standard for nethyi mercaptanin air of residentiai area
This standard specifies the maximum allowable concentration of methyl mercaptan in the air of residential areas and its monitoring and inspection methods. This standard is applicable to the measurement and evaluation of the atmospheric environment in residential areas. 2 Standard limit
The second maximum allowable concentration of methyl mercaptan in the air of residential areas is 0.0007 mg/m3. 3 Monitoring and inspection methods
This standard adopts the p-aminodimethylaniline colorimetric method, see Appendix A (Appendix to the standard) for details. Approved by the State Administration of Quality and Technical Supervision on April 10, 2000 42
GB 18056 - 2000
Implementation on January 1, 2001
A1 Principle
GB18056-2000
Appendix A
(Appendix to the standard)
p-Aminodimethylaniline colorimetric method
Absorb mercaptan (R-SH) in an aqueous solution of mercuric acetate-glacial acetic acid. In the presence of strong acidic solution and ferric chloride, mercaptan reacts with p-aminodimethylaniline to form a red complex. The color is quantitatively determined based on the color depth. A2 Reagents
A2.1 Mercuric acetate [(CH,COO), Hg): analytical grade. A2.2 Glacial acetic acid CH;COOH (analytical grade). A2.3 p-Aminodimethylaniline hydrochloride (C,H4·N(CHs)22HCl), analytical grade. A2.4 Ferric chloride (FeCl3·6H20): analytical grade. A2.5 Nitric acid (HNO,): superior grade.
A2.6 Lead methylmercaptan (Pb(CH,SH),). A2.7 Absorption solution: 50g of mercuric acetate, add 400mL of distilled water, 25mL of glacial acetic acid, and dilute to 1L with water. A2.8
Ferric chloride-nitric acid solution: 67.6g of ferric chloride is diluted to 500mL with distilled water, and 72mL of concentrated nitric acid (relative density 1.42) is taken and diluted to 500mL with water.
A3 Sampling
A3.1 Container: brown large porous plate absorption bottle. A3.2 Method: 15mL of absorption solution is placed in the gas sampling bottle, the gas sampling volume is 60~~180L, and parallel samples are collected. A4 Analysis steps
A4.1 Drawing a standard curve: The methyl mercaptan standard solution used in this method is prepared with methyl mercaptan lead, the absorption liquid is 5% mercuric acetate glacial acetic acid solution, 2mL of color developer (a mixture of 6 volumes of 0.5% p-aminodimethylaniline hydrochloric acid solution and 1 volume of ferric chloride-nitric acid solution), add water to 25mL and mix well, let it stand for 30 minutes, use a 3cm colorimetric cup, and measure the absorbance at a wavelength of 500nm. Draw a standard curve based on the absorbance and the mass of methyl mercaptan contained (μg).
A4.2 Sample determination
After sampling, transfer all the absorption liquid into a 23mL colorimetric tube, wash the absorption bottle with 5-6mL distilled water, and pour it into the colorimetric tube. After adding the color developer, measure the optical density according to the standard curve steps, check the standard curve, and obtain the mass of methyl mercaptan contained in the colorimetric tube (ug). A5 Calculation results
Calculation is calculated according to formula (A1).
-Methyl mercaptan concentration, mg/m;
Wherein: c——
-Methyl mercaptan mass, ug;
V——Sampling volume converted to standard conditions, L. A6 Description
The detection limit of this method is 0.04μg/mL.
（A1)
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