This standard specifies the determination of chloropicrin in workshop air by the spectrophotometric method using naphthylethylenediamine hydrochloride. This standard is applicable to the determination of chloropicrin concentration in the air of workplaces where chloropicrin is manufactured, processed, or used as a disinfectant. GB/T 16101-1995 Spectrophotometric determination of chloropicrin in workshop air using naphthylethylenediamine hydrochloride GB/T16101-1995 Standard download decompression password: www.bzxz.net

ICS13.040.30
National Standard of the People's Republic of China
GB/T16101—1995
Workplace air--Determination of chloropicrinNaphthyl ethylenediamine dihydrochloridespectrophotometric method
Published on January 23, 1996
State Bureau of Technical Supervision
Ministry of Health of the People's Republic of China
Implemented on July 1, 1996
National Standard of the People's Republic of China
Workplace air-Determination of chloropicrin-Naphthyl ethylenediamine dihydrochloridespectrophotometric method method
1 Subject content and scope of application
This standard specifies the determination of chloropicrin in workshop air by the spectrophotometric method with naphthalene ethylenediamine hydrochloride. GB/T16101-1995
This standard applies to the determination of chloropicrin concentration in the air of the workplace where nitropicrin is manufactured and processed and chloropicrin is used as a disinfectant and insecticide. 2 Principle
Ammoniated picrin is decomposed by sodium ethoxide to generate sodium nitrite, which reacts with p-aminobenzenesulfonic acid and naphthalene ethylenediamine hydrochloride in an acidic solution to generate a red compound for colorimetric quantification.
3 Instruments
3.1 Porous glass plate absorption tube. wwW.bzxz.Net
3.2 Vacuum pump.
3.3 Flowmeter, 0~2L/min.
3.4 ​​Stoppered colorimetric tube, 10mL.
3.5 Spectrophotometer, 20mm colorimetric cup.
4 Reagents
4.1 Absorption solution: Measure 500mL of anhydrous ethanol into a 1000mL beaker, add 2.5g of metallic sodium fragments (after taking the metallic sodium out of the bottle, first use filter paper to absorb the kerosene on the surface, cut off the oxidized part with a knife, and then rinse with anhydrous ethanol 2-3 times). When the reaction is completed and no more bubbles appear in the cup, store the ethanol solution in a brown bottle and seal it. 4.2 Hydrochloric acid solution, c(HCI)=3mol/L. 4.3 Color developer: Weigh 5g of p-nitrobenzenesulfonic acid and dissolve it in 800-900mL of water containing 50mL of glacial acetic acid, then add 0.05g of naphthylethylenediamine hydrochloride, dilute to 1L after dissolution, and store in a brown bottle. 4.4 Chloropicrin standard solution: Add 10mL of anhydrous ethanol to a 25mL volumetric flask, weigh accurately, add 2 drops of pure chloropicrin, and weigh accurately again; the difference between the two weighings is the mass of chloropicrin. Dilute to scale with anhydrous ethanol, calculate the content of chloropicrin in 1mL of this solution (stock solution), and store in a refrigerator. Before use, absorb a certain amount of stock solution and dilute it with absorption liquid to a standard solution of 1mL=10μg nitride picrin. Leave it for at least 3h and use it after the nitride picrin is completely decomposed. 5 Sampling
Use a porous glass plate absorption tube containing 5mL of absorption liquid to extract 2.5L of air at a rate of 0.25L/min. Approved by the State Administration of Technical Supervision on December 15, 1995, and implemented on July 1, 1996
6 Analysis steps
6.1 Control test
GB/T16101—1995
Use 5mL of absorption liquid in the absorption tube brought to the site but not sampled, and treat it in the same way as the sample determination operation as a blank control.
6.2 Sample treatment
Wash the air inlet pipe 2 to 3 times with the absorption liquid in the absorption tube, and draw 2mL of the sample solution into the colorimetric tube for determination. 6.3 Standard curve drawing
Prepare standard tubes according to the table below, and add 0.2mL of hydrochloric acid (4.2) to each tube, spread it, and then add 8mL of color developer (4.3), shake it well: let it stand for 30 minutes, and use a 20mm colorimetric cup to measure the absorbance of each tube at a wavelength of 540nm. Draw a standard curve or perform regression processing. Preparation of chloropicrin standard tube
Chloropicrin standard solution, mL
Absorbent solution, mL
Chloropicrin content, ug
6.4 Determination
Add hydrochloric acid and color developer in the same way as the standard tube and determine the absorbance. Detect the chloropicrin content in 2mL sample solution according to the standard curve (or regression equation).
7 Calculation
7.1 Calculate the sample volume under standard conditions according to formula (1): 273
273+#
Where: V. Sample volume under standard conditions, L, V
Sample volume, L;
tTemperature, ℃,
Atmospheric pressure, kPa.
7.2 Calculate the concentration of chloropicrin in the air according to formula (2): 2.5C
Wherein, X is the concentration of chloropicrin in the air, mg/mC is the content of chloropicrin in 2mL sample solution, \g1V. ——The volume of the sample under standard conditions, L. 8 Notes
(1)
· (2)
8.1 The detection limit of this method is 0.25μg/2mL, the linear range is 1~12μg/2mL, and the coefficient of variation at 1, 6, and 10μg/2mL are 7.9%, 2.0% and 0.52% respectively.
8.2 When the concentration of nitrified bittern in the air is 12.6~32.7mg/m3, the sampling efficiency is 93.7%~99.8%, and the average is 96.5%. Therefore, 2
GB/T16101-1995
It is not necessary to connect two absorption tubes in series for sampling. When the temperature is high, the absorption tube should be placed in an ice bath for sampling. 8.3 The decomposition reaction of nitrified bittern by sodium ethoxide is slow, and it takes more than 2 hours. It must be placed for 3 hours before the next determination and treatment. In addition, the efficiency of this decomposition reaction is generally only 85%~95%. Therefore, it is not appropriate to use sodium nitrite to replace nitrified bittern to prepare the standard solution. 8.4 Hydrochloric acid is added to neutralize the alkalinity of sodium ethoxide. Adding acetic acid cannot reach the pH value for color development. Experiments show that adding 0.2mL3mol/L hydrochloric acid has the best effect.
Additional instructions:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Hunan Provincial Institute of Labor Hygiene and Occupational Disease Prevention and Control and the Sichuan Provincial Health and Epidemic Prevention Station. The main drafters of this standard are Zhang Zhaoping, Wu Gaoxu, Yan Jiaqing and Zhao Chengli. 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. National Standard of the People's Republic of China
Spectrophotometric Determination of Fluoropicrin in Workplace Air by Ethylene Diamine Hydrochloride
GB/T16101—1995
Published by China Standards Press
No. 16, Sanlihe North Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 68522112
Published by China Standards Press Printed by Qinhuangdao Printing House, Xinhua Bookstore, Beijing Distribution Office, Xinhua Bookstores in all regions, copyright reserved, no reproduction allowed
Format: 880×12301/16 Printing sheet: 1/2
Word count: 5,000
First edition: October 1996, first printing: October 1996, print run: 1-3000
Book number: 155066·1-12990
Heading: 295-48
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