Some standard content:
National Standard of the People's Republic of China
Health standard for ethylene glycol in the air of workplace
Health standard for ethylene glycol in the air of workplace1 Subject content and scope of application
This standard specifies the maximum allowable concentration of ethylene glycol in the air of workplace and its monitoring and inspection methods. This standard applies to all types of enterprises that produce and use ethylene glycol. Hygienic requirements
The maximum allowable concentration of ethylene glycol in the air of workplace is 20mg/m3. 3 Monitoring and inspection methods
The monitoring and inspection methods of this standard adopt gas chromatography, see Appendix A. 4 Supervision and implementation
Health administrative departments at all levels are responsible for supervising the implementation of this standard. Approved by the State Administration of Technical Supervision on April 3, 1996 102
GB16190—1996bzxZ.net
Implementation on September 1, 1996
A1 Principle
GB16190—1996
Appendix A
Gas chromatography
(Supplement)
Use a silicone tube to collect ethylene glycol in the air, desorb it with a 2% isopropanol aqueous solution, inject it, separate it on a SE-30 column, and detect it with a hydrogen flame ionization detector. The retention time is used for qualitative analysis and the peak height is used for quantitative analysis. A2 Instrument
Silicone sampling tube, a glass tube with a length of 10 cm, an inner diameter of 4 mm, and an outer diameter of about 6 mm, is filled with two sections of 20-40 mesh silica gel, the front section is filled with 500 mg, and the rear section is filled with 250 mg. The middle and both ends are separated and fixed with glass wool, and sealed for use. Sampling pump, 0~～1L/min.
Micro syringe, 5μL, 1μul.
Test tube with stopper, 5ml.
Oscillator, multi-purpose oscillator.
Gas chromatograph, hydrogen flame ionization detector, 0.2μg ethylene glycol gives a signal-to-noise ratio of not less than 3:1. A3 Reagents
A3.1 Silica gel: crush the primary silica gel, sieve, select 20-40 mesh silica gel and put it in a beaker, add 1:1 sulfuric acid and nitric acid mixture to 1-2cm above its surface, soak overnight, discard the acid solution, wash with distilled water several times until there is no sulfate ion. Then, dry at 110℃, activate at 360 for 3h, take out and put into a desiccator for use. A3.2 Ethylene glycol, analytical grade.
A3.32% isopropanol aqueous solution.
A3.4SE-30 chromatographic stationary liquid.
A3.5 Red diatomaceous earth chromatographic support Chromosorb101, 60-80 mesh. A4 Sampling
Open both ends of the sampling tube at the sampling site, connect the 250mg end to the sampling pump and place it vertically, extract 10-301 air at a speed of 0.5L/min, and immediately put plastic caps on both ends of the tube after sampling. A5 Analysis steps
A5.1 Chromatographic conditions
Chromatographic column: column length 2m, inner diameter 4mm, stainless steel column, SE-30?Chromosorb101 support = 5:100. Column temperature: 170℃. a. Food
Vaporization chamber temperature: 250℃.
c Detection chamber temperature: 200℃.
d. Carrier gas (nitrogen): 35mL/min.
A5.2 Drawing of standard curve
In a 10mL volumetric flask, first add a small amount of distilled water, accurately weigh it, use a graduated pipette to measure a certain amount of ethylene glycol (specific gravity 1.1135) and add it to the volumetric flask, then accurately weigh it, add water to the scale to prepare a certain concentration of stock solution. Before use, take a certain amount of stock solution and dilute it with 2% isopropanol aqueous solution to 0.4, 1.0, 2.0, 3.0, 4.0 mg/mL ethylene glycol standard solution, take 1μL of each sample, measure the retention time and peak height, repeat three times for each concentration, and take the average value of the peak height. Plot the ethylene glycol content against the peak height to draw a standard curve. Retention time is a qualitative indicator. 403
A5.3 Sample analysis
GB16190—1996
Put the two sections of silica gel in the front and back of the silica gel tube after sampling into 5mL stoppered test tubes, add 2mL of 2% isopropanol aqueous solution, plug the tubes tightly, and oscillate on an oscillator for 15min (or place for 1h for desorption). Take 1μl. Inject, use retention time for qualitative analysis and peak height for quantitative analysis. See Figure A1 for the ethylene glycol chromatogram.
Time. min
Ethylene glycol chromatogram
A6 Calculation
X 2 000
Concentration of ethylene glycol in the air, mg/m;
Wherein: X-
C, (2—Ethylene glycol content in the isopropanol water desorption liquid taken from the front and rear silica gel, ug, V.——Sampling volume under standard conditions, I.. A7 Description
(Al)
A7.1 The detection limit of this method is 0.2μg (liquid injection 1μL), which can meet the monitoring requirements of health standards. When the ethylene glycol concentration is 0.4, 1.0, 2.0, 3.0 and 4.0μg/mL When the relative humidity of air is greater than 84%, the coefficient of variation is 3.8%, 4.9%, 3.6%, 4.9% and 2.6% respectively, and the precision of the method meets the requirements. A7.2 When the relative humidity of air is greater than 84%, the penetration capacity of the 500mg silicone tube test is greater than 18mg at a rate of 0.5L/min using 260mg/m2 ethylene glycol standard gas, indicating that the silica gel has a good adsorption effect on ethylene glycol. The results of the silicone tube in the field sampling also show that the sampling efficiency of the front section silica gel (500mg) can generally reach 100%. 10
GB 16190—1996
A7.3 The desorption efficiency of a compound may vary from laboratory to laboratory and from different batches of silica gel to different batches. Therefore, the desorption efficiency must be re-calculated for different laboratories and when changing the batch of silica gel. Under the conditions of this experiment, the desorption efficiency of ethylene glycol is between 95.4% and 98.8%, and its coefficient of variation is below 5.9%. A7.4 When sampling, the front end of the sampling tube should not be connected to other tubes. Let the sample enter the sampling tube directly. After sampling, both ends should be immediately sealed with plastic caps to prevent contamination. The recovery rate is above 91% after being stored at room temperature for 14 days. A7.5 If there are substances with a retention time close to that of ethylene glycol at the sampling site, it will interfere with the determination. In this case, it can be eliminated by changing the chromatographic separation conditions.
Additional Notes:
This standard is proposed by the Ministry of Health of the People's Republic of China. This standard is drafted by the Shenyang Institute of Labor Hygiene and Occupational Diseases. The main drafters of this standard are Yin Longzan and Lin Shulian. This standard is interpreted by the Institute of Labor Hygiene and Occupational Diseases, Chinese Academy of Preventive Medicine, which is entrusted by the Ministry of Health. 405
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