This standard specifies the maximum permissible concentration of isophorone diisocyanate in the air of a workplace and its monitoring and testing methods. This standard is applicable to all types of enterprises that produce and use isophorone diisocyanate. GB 16234-1996 Hygienic standard for isophorone diisocyanate in the air of a workplace GB16234-1996 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Health standard for isophorone disocyanate (IPDI) in the air of workplace
Subject content and scope of application
GB 16234—1996
This standard specifies the maximum allowable concentration of isophorone diisocyanate in workplace air and its monitoring and inspection methods. This standard is applicable to all types of enterprises that produce and use isophorone diisocyanate. 2 Hygiene requirements
The maximum allowable concentration of isophorone diisocyanate in workplace air is 0.1 mg/m (skin). 3 Monitoring and inspection methods
The monitoring and inspection methods of this standard adopt high performance liquid chromatography, see Appendix A (supplement). Approved by the State Administration of Technical Supervision on April 3, 1996, and implemented on September 1, 1996
A1 Principle
GB16234—1996
Appendix A
High Performance Liquid Chromatography
(Supplement)
Use pyridine piperazine-glass fiber filter paper to collect isophorone diisocyanate (IPDI) in the air. IPDI reacts with pyridine piperazine [1-(2-pyridyl)piperazine, 2PP] to form IPDI-urea, which is extracted with methanol-ammonium acetate solution. The extract is separated by a reverse C18 column of a high performance liquid chromatograph and detected by a UV detector. The retention time is qualitative and the peak height is quantitative. A2 Instruments
A2.1: High performance liquid chromatograph (with UV detector). A2.2 Sampling clamp.
A2.3 Air sampler, flow rate 0.1～3L/min. A2.4 Pyridine piperazine-glass fiber filter paper: Place g37mm glass fiber filter paper in a fume hood, take 0.5mL of pyridine piperazine absorption solution and quickly drop it on each filter paper, and let it stand for 5 minutes to dry slightly. A2.5 Stoppered colorimetric tube, 10mL.
A2.6 Micro syringe, 40μL.
A3 Reagents
A3.1 Methanol: redistilled, analytical grade.
A3.2 Pyridine piperazine absorption solution: Weigh 80mg of pyridine piperazine and dissolve it in 100mL of dichloromethane. A3.3 Ammonium acetate solution, 0.1mol/L.
A3.4 Preparation of IPDI-urea: Take 280μL pyridine piperazine and dissolve it in 3mL dimethyl sulfoxide (DMSO) (solution A), and take another 178uL IPDI and dissolve it in 3mL DMSO (solution B); slowly pour solution B into solution A and stir, place in a 60℃ water bath for 30min, then slowly add 200mL redistilled water, and white precipitate can be seen to precipitate, filter it through qualitative filter paper, vacuum dry it, and then recrystallize it with 3mL dimethylformamide and 200mL redistilled water, filter it, and dry it, which is IPDI-. A3.5 IPDI standard solution: weigh 0.988mg IPDI-urea (A3.4), dissolve it with mobile phase solution, transfer it into a 100mL volumetric flask, add mobile phase solution to the scale, this solution 1mL = 4μg IPDI. Dilute it into 1mL = 0.1, 0.2, 0.4μg IPDI standard solutions before use.
A4 Sampling
Place the pyridine piperazine-glass fiber filter paper in the sampling clip and collect 15L of air at a speed of 1.0L/min. A5 Analysis Steps
A5.1 Chromatographic Conditions
Chromatographic column: column length 200mm, inner diameter 5mm, stainless steel column; column packing: C18:
Column temperature: room temperature;
Mobile phase: methanol: ammonium acetate solution (0.1mol/L) = 78:22; flow rate: 1ml./min;
Detector: UV detector, wavelength 310 or 254nm. 540
A5.2 Drawing of standard curve
GB 16234-1996
Take 250μL of IPDI standard solution of different concentrations, inject into high performance liquid chromatograph, measure retention time and peak height, repeat 6 times for each concentration, take the average value of peak height, plot IPDI concentration against peak height, and draw standard curve. Retention time is a qualitative indicator. A5.3 Control test
Same as A4, but use pyridine piperazine-glass fiber filter paper (A2.4) that has not been sampled and treat it in the same way as the sample treatment operation as a blank control.
A5.4 Sample treatment
Carefully clip out the glass fiber filter paper in the sampling clip, put it into a stoppered colorimetric tube, add 5mL of mobile phase solution, crush the filter paper with a clean glass rod, soak for 30 minutes, filter with qualitative filter paper for use. A5.5 Determination
Take 250μL sample solution for injection, use retention time for qualitative analysis and peak height for quantitative analysis. The IPDI chromatogram is as follows:12PP
IPDI-urea
Figure A1 Typical IPDI-urea HPLC Chart
A5.6 Calculation
Where: X—IPDI concentration in air, mg/m; C—IPDI concentration in sample solution, μg/mL; V. ——Converted to sampling volume under standard conditions, L. 5.C
（A1）
A6 Explanation
GB16234—1996bzxZ.net
A6.1 The detection limit of this method is 0.013mg/mL. When the IPDI concentration is 100, 200, and 400ng/mL, the coefficient of variation is 9.0%, 1.4%, and 1.6%, respectively. The sampling efficiency is 98.85%, and the elution efficiency is 98.3%. A6.2 When adding the absorption liquid to the glass fiber filter paper, it should be fast and completely permeate the entire filter paper. The amount of absorption liquid can be slightly more but not too less. A6.3 The treated filter paper can be sealed in the sampling clamp and placed in the refrigerator for long-term storage. After sampling, store it at room temperature and measure it within one week. A6.4 Do not attach any tube in front of the sampling clamp to reduce the chance of IPDI adhering to the wall, so that it can completely reach the surface of the filter paper and be retained. Additional instructions:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard was drafted by the Industrial Toxicology Laboratory of Tongji Medical University. The main drafters of this standard are Jiang Yun, Zhang Zhaodi and Qin Chunhua. This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases of the Chinese Academy of Preventive Medicine, which is the technical unit entrusted by the Ministry of Health.
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