This standard specifies the determination of aniline in workshop air by the spectrophotometric method using naphthylethylenediamine hydrochloride. This standard is applicable to the determination of aniline concentration in the air of aniline production and use sites. GB/T 16100-1995 Spectrophotometric determination of aniline in workshop air using naphthylethylenediamine hydrochloride GB/T16100-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Workplace air-Determination of anilineNaphthyl ethylenedianine diliydrochloridespectrophotometric method
1 Subject content and scope of application
This standard specifies the determination of aniline in workshop air by the naphthyl ethylenedianine diliydrochloride spectrophotometric method. This standard is applicable to the determination of aniline concentration in the air of amine production and use sites. 2 Principle
GB/T 16100—1995
In an acid solution, aniline reacts with ethylamine hydrochloride after diazotization to form a purple color, which is lower than the colorimetric standard. 3 Instruments
3.1 Large gas pool absorption tube
3.2 Vacuum pump
3.3 Flow meter. 0~-1L/rmin
3.4 ​​H-cold colorimetric tube, 10ml
3.5 Spectrophotometer, 20mm cup.
4 Reagents
4. 1 Absorption liquid: hydrochloric acid: (HC1) = C. 02 mol/L4.2 Sodium nitrate solution. 32mol/L, prepared before use. 4.3 Ammonium sulfonate solution. 20R/L,
4.4 Hydrochloric acid diethylenediamine solution. 10/L, stored in ice, can be used for one week. 4.5 Standard solution: Put 10mL of absorption liquid in a 25ml volumetric flask, weigh it accurately, add 2 drops of fresh aniline, weigh it accurately again. The difference between the two weighings is the mass of aniline, add absorption liquid to the scale, and calculate the content of aniline in the solution. Dilute the absorption liquid to 1ml = 10g of aniline standard solution. Connect two large bubble absorption tubes filled with 10ml absorption liquid, and extract 11% air at a speed of 0.51/min. 6 Analysis steps 6.1 Control test: 1 Take samples, take the absorption tubes with absorption liquid to the site, but do not extract air, and analyze the samples as a reference. 6.2 Sample treatment: Wash the inner tube of the absorption tube with the absorption liquid for 3 times, and take 5.0ml of sample liquid from the two absorption tubes and put them into the colorimetric tubes.
GB/T 16100
6.3 Drawing of standard curve: Prepare the standard tube of aniline according to the table below. 1995
Preparation of aniline standard tube
Standard aniline solution (.), ml.
Absorbent solution (i). ml.
Add 0.1ml of sodium nitrite solution (4.2) to each standard tube, shake, let stand for 10min, then add 0.5ml of ammonium amine solution (4.3), shake thoroughly until bubbles appear, let stand for 5min, add 1mL of naphthylethylamine hydrochloride solution (4.4). Add water Dilute with 10ml probe spoon, cover for 15min, use 20mm colorimetric cup, measure absorbance at 60nm wavelength. Plot absorbance against aniline content (g/5ml). Draw standard curve.
6.4 Sample determination: Sample tube operation [standard tube, measure absorbance and then draw standard curve to find out the content of benzene stock 7 calculation
7.1 According to formula (1), convert the sample volume into the volume under standard state. V=vX
273+ t
Where: V, sample volume under standard conditions. L; sample volume, I
temperature, C:
atmospheric pressure, kPa. www.bzxz.net
7.2 Use formula (2) to calculate the concentration of aniline in air. Where: X is the concentration of aniline in air, mg/m\; Ghc
8 Explanation
X = 2(GC)
is the content of aniline in the sample solution taken from the first---and the second absorption tube, respectively, g is the sample volume under standard conditions, L,
8.1 The detection limit of this method is 0./5ml.; the carbon concentration is when the colorimetric volume is 5ml., 1 aniline should have an absorbance of 0.065, and the determination range of this method is 0.5~8\g/5mL: when the concentration of benzene is 2.0.1.0, 6.0g/5ml, the coefficient of variation is 3. 3%, 4.2% and 1.4%.
8.2 Connect two human-shaped bubble absorption tubes in series, each containing 10ml of absorption liquid. Sampling at a speed of 0.5l/min for 2min. When the concentration of aniline in the air is 1.2~~11.0g/m3, the sampling efficiency of the front tube is 93.6%-~95.0%. 8.3 The sample collection should be completed after the analysis is completed. The color should be completely developed in 15min and the color should be stable for at least 2h. 8.4 The acidity selected in the determination step is suitable for sodium sulfonate and ethylenediamine hydrochloride. After adding ammonium sulfonate, it is necessary to pay attention to shaking to remove excess Use sodium nitrate, avoid excessive sodium nitrite and react with ethylamine hydrochloride to produce bezoar color, which is colorimetric. 8.5 Methylamine and aniline interfere with the determination of benzene, while nitrobenzene has no interference with the determination of aniline. Additional remarks:
GB/T16100—1995
This standard was proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Guangdong Provincial Institute for Occupational Disease Prevention and Treatment and the Sichuan Provincial Health and Epidemic Prevention Station. The main drafters of this standard are Ye Nengquan, Chen Li and Wu Xu. This standard was entrusted by the Ministry of Health to the Institute of Labor Health and Occupational Diseases, Chinese Academy of Preventive Medicine, which is responsible for the interpretation.
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