This standard specifies the maximum permissible concentration of acetone cyanohydrin in the workplace and its monitoring method. This standard is applicable to all types of industrial enterprises that produce and use acetone cyanohydrin. GB 18551-2001 Occupational exposure limit of acetone cyanohydrin in workplace air GB18551-2001 Standard download decompression password: www.bzxz.net

GB18551—2001
This standard is formulated for the first time based on toxicological experiments, on-site labor hygiene surveys, epidemiological survey data and reference to foreign occupational exposure limits. It is a health standard used for workplace environmental monitoring and health supervision. Appendix A of this standard is the appendix to the standard. This standard is proposed by the Ministry of Health of the People's Republic of China. Drafting unit of this standard: Labor Hygiene Teaching and Research Section of Sun Yat-sen University of Medical Sciences: The main drafter of this standard is Xu Famo.
This standard is entrusted to the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine for interpretation. 693
1 Scope
National Standard of the People's Republic of China
Occupational exposure limit for acetone cyanohydrin in the air of workplace
This standard specifies the maximum allowable concentration of acetone cyanohydrin in the air of workplace and its monitoring method. This standard is applicable to various industrial enterprises that produce and use acetone cyanohydrin. 2 Hygiene requirements
The maximum permissible concentration of acetone cyanohydrin in the air of the workshop is 3mg/m3 (skin). 3 Monitoring and inspection methods
GB 18551--2001
The monitoring and inspection methods of this standard adopt the sodium isonicotinate-sodium barbiturate spectrophotometric method, see Appendix A (Appendix to the standard). Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on December 4, 2001694
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Implementation on May 1, 2002
A1 Principle
GB18551-2001
Appendix A
[Appendix to the standard]
Sodium isonicotinate-sodium barbiturate spectrophotometric method for acetone cyanohydrin in the air of the workshop The acetone cyanohydrin in the air is absorbed by sodium hydroxide solution and decomposed into acetone and hydrogen sulfide under alkaline conditions. The generated hydrogen xenon is quantified by the sodium isonicotinate-sodium barbiturate colorimetric method.
A2. Apparatus
A2.1 Large bubble absorption tube. www.bzxz.net
A2.2 Air sampler: flow rate α~1 L/min. A2.3 Stoppered colorimetric tube: 10 mL.
A2.4 Constant temperature water bath.
A2.5 Spectrophotometer.
A3 Reagents
Absorption: sodium hydroxide solution, 0.1 mol/L. A3.2 Phenolic acid solution, 2 g/I
A3.3 Acetic acid solution, 1+20.
A3.4 Phosphate buffer solution (pH=5.8) Dissolve 8.0 g potassium dihydrogen phosphate (KH2PO4) and 7.6 g sodium dihydrogen phosphate (Na2HPO4,12H2O) in 1 L of water.
A3.5 Chloramine T solution (1) g/I.): Prepare before use. A3.6 Sodium isonicotinate-barbituric acid colorimetric agent: Dissolve 1g isonicotinate and 1g barbituric acid in 100mL absorption solution, filter, place the filtrate in a brown bottle, and store in the refrigerator for later use.
A3.7 Standard solution: Add 10mL of water to a 50mL volumetric flask, weigh it, add 3 drops of acetone cyanohydrin, weigh it again, and add water to the scale. Calculate the content of acetone cyanohydrin in 1ml of solution. Then dilute with absorption liquid to prepare (.1mg/mL acetone cyanohydrin stock solution, which can be stored for ten days at room temperature and months in the refrigerator. Dilute with absorption liquid to 10.01g/mL acetone cyanohydrin standard solution before use. A4 Sampling
Connect two large bubble absorption tubes each containing 5.0mL absorption liquid, and collect 2L of air at a flow rate of 0.2L/min. A5 Analysis steps
A5.1 Control test: Take the absorption tubes filled with absorption liquid to the site, except that no air is extracted, and the rest of the operation As a companion sample, as a blank control of the sample,
45.2 Sample treatment: Wash the inner wall of the absorption tube with the absorption liquid of the absorption tube 3 times, then measure 1.0ml of sample solution from each absorption tube and put it into a 10mL colorimetric tube. Add absorption liquid to 5.0mL. A5.3 Drawing of standard curve: Prepare standard tubes according to Table A1. 693
Standard solution, ml.
Absorption liquid.mL
Acetone cyanohydrin concentration-pg/mL
GB 185512001
Preparation of acetone cyanohydrin standard tube
Add 1 drop of phenolic acid solution to each standard tube, neutralize with acetic acid solution until phenolic acid fades, add 1.5mL phosphate buffer and 0.2mL chloramine T solution to each tube, mix well, cover and plug tightly, and place for 5 minutes. Add 2.5mL sodium isonicotinate-sodium barbiturate colorimetric agent to each tube, add water to 10mL, mix well, place at 25~40C for 10 minutes, measure the absorbance at a wavelength of 599nm, and draw a standard curve based on the measured absorbance value and the concentration of acetone cyanohydrin.
A5.4 Sample determination: Measure the absorbance of the sample tube and the blank control tube in the same way as the standard tube, and calculate the concentration of acetone cyanohydrin in the sample tube from the standard curve.
A6 Calculation
A6. 1Convert the sampling volume into the sample volume under standard conditions according to formula (A1). 273
In the formula, V. —Converted into the sampling volume under standard conditions, I.: 101.3
V--the incoming sample volume when the atmospheric pressure is pkPa and the air temperature is tC, L; the air temperature at the incoming sample point, C:
pThe atmospheric pressure at the sampling point, kPa.
A6.2Calculate the concentration of acetone fluoride alcohol in the air according to formula (A2). 5(ci + cs)
wherein.c-
concentration of acetone cyanohydrin in the air, ng/mn; ci\~concentration of acetone cyanohydrin in the sample solution taken from the front absorption tube, μug/mL; c-concentration of acetone cyanohydrin in the sample solution taken from the rear absorption tube, g/tmLIVo
converted to sample volume under standard conditions, L. A7 Notes
(A2)
A7. 1 The detection limit of this method is 0, 020 g/mL. When 2 L of air is collected, the minimum detection concentration is 0. 05 mg/m, which meets the requirements of on-site sampling.
A7.2 The sampling efficiency of this method is above 95%. A7. 3 The best choice of absorption liquid is 0. 10 mol/L sodium hydroxide. A7.4 Selection of color development time: After adding 0.10mol/L sodium hydroxide to the absorption liquid, the absorbance value of the hydrolysis color development time of 30~～100min is basically the same.
A7.5 Selection of water temperature: the water temperature between 25 and 40°C has no significant effect on the hydrolysis reaction of acetone cyanohydrin. A7.6 Sample storage stability: the deviation of the sample after 7 days of storage is less than 10%. A7.7 Acetone, hydrocyanic acid and hydrazine hydrate interfere with the determination and must be excluded. 696
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