This standard specifies the determination of carbon disulfide concentration in the atmosphere of residential areas by gas chromatography. This standard applies to the determination of carbon disulfide concentration in the atmosphere of residential areas. GB/T 11741-1989 Standard method for hygienic examination of carbon disulfide in the atmosphere of residential areas Gas chromatography GB/T11741-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Gas chromatography for hygienic examination of carbon disulfide in air of residential areas
Standard method
Standard method for hygienic examination of carbon disulfide in air of residential areas-Gas chromatography
Subject content and scope of application
This standard specifies the determination of carbon disulfide concentration in the atmosphere of residential areas by gas chromatography. This standard is applicable to the determination of carbon disulfide concentration in the atmosphere of residential areas. 1.1 Detection limit
When the sample is 5mL, the minimum detection concentration is 0.01mg/㎡. 1.2 Determination range
When the sample is 5mL, the determination concentration range is 0.01～12.6mg/m2. 1.3 Interference and elimination
GB 11741-89
Due to the use of gas chromatography separation technology, under the operating conditions of this method, air, hydrogen sulfide and sulfur dioxide do not interfere with the determination. The interference of dimethyl sulfide can be eliminated by reducing the column temperature to below 75°C. 2 Principle
After carbon disulfide is completely separated from other components of the air in the chromatographic column, it enters the reducing hydrogen-rich flame to generate molecular sulfur and emit characteristic light of 394nm wavelength, which is converted and amplified into a voltage value. In the range of 1 to 103, the logarithm of the carbon disulfide concentration is proportional to the logarithm of the voltage value for determination.
3 Reagents and materials
3.1 Carbon disulfide: chromatographically pure or spectrally pure. 3.2 Indole: analytically pure.
3.3 Trisyl phosphate (TCP): analytically pure or "color-fixed" standard, used as a chromatographic stationary liquid. 3.4 Support: Chromosorb PNAW 60 to 80 mesh, used as a chromatographic support. 3.5 Stationary phase: coated at a 25% liquid-to-support ratio. Weigh 2.5g TCP in a 100mL beaker, add 30mL acetone to dissolve, then pour in 10g Chromosorb PNAW, so that the support is just submerged, shake gently, and let it stand at room temperature to evaporate. 4 Instruments and equipment
4.1 Gas chromatograph: gas chromatograph equipped with flame photometer. 4.2 Syringes: 100μL, 1mL, 5mL, 10mL, 100mL. Volume error ±1%. Chromatographic column: 1.5m long, 4mm inner diameter polytetrafluoroethylene tube, filled with 25% TCP Chromosorb PNAW. New 4.31
chromatographic columns should be aged for 11h at a column temperature of 120℃ and nitrogen flow of 40mL/min before use. Approved by the Ministry of Health of the People's Republic of China on September 21, 1989 528
Implemented on July 1, 1990
5 Sampling
GB 11741-89
After repeatedly pumping and replacing the air with the on-site air for 6 times, fill the 100mL syringe with 100mL and seal the air inlet. Write a label to indicate the sampling location and time. The sample must be analyzed within 24 hours. 6 Analysis steps
6.1 Chromatographic analysis conditions
Since chromatographic analysis conditions often vary depending on experimental conditions, the best chromatographic conditions for analyzing carbon disulfide should be formulated based on the model and performance of the gas chromatograph used. The chromatographic conditions listed in Appendix A (reference) are examples. 6.2 Drawing standard curves and determining correction factors Drawing standard curves or determining correction factors under the same conditions as when analyzing samples. 6.2.1 Preparation of standard gas
6.2.1.1 Preparation of standard gas with saturated steam Place pure carbon disulfide in a constant temperature bath (20-30℃, temperature control accuracy is ±0.1℃) and keep the temperature constant for 40 minutes. Then extract the saturated steam on the liquid surface in the bottle and dilute it with nitrogen to form standard gas with concentration points of 1/108-1/1054. When transferring saturated steam, pay special attention to the loss caused by condensation of saturated steam and adsorption on the wall. The concentration of standard gas is calculated according to formula (1). co
Formula, co-standard gas concentration, ng/mL, n-dilution factor,
dt The concentration of saturated steam at constant temperature, ng/mL, can be obtained by referring to Figure B1. 6.2.1.2 Prepare standard gas by using the large bottle dilution method. (1)
A certain amount of pure carbon disulfide (e.g. 252 mg) is sealed in a glass bottle and placed in a large glass bottle with a volume of 20 L. The large bottle is sealed and then the gas is pumped out until the pressure inside the bottle is less than 7 kPa. The large bottle is shaken to break the bottle. After standing for 10 min, nitrogen (or purified air) is added to make the pressure inside the large bottle equal to the atmospheric pressure. Then, the standard gas is diluted with nitrogen or purified air to form a standard gas with concentration points of 1/103 to 1/1064. The concentration of the standard gas is calculated according to formula (2). Www.bzxZ.net
In the formula: α -
- the amount of carbon disulfide in the glass bottle, mg,
- the volume of the large glass bottle, L
- the dilution factor;
- the concentration of the standard gas, ng! mL.
6.2.2 Draw the standard curve
(2)
Take 5mL of the standard gas at each concentration point and inject it to obtain the chromatographic peak and retention time of each concentration. Perform three times for each concentration, calculate the average peak height, use the logarithm of the average peak height (mm) as the ordinate, and the logarithm of the carbon disulfide concentration (mg/m3) as the abscissa to draw the standard curve. Calculate the slope of the regression line and use the inverse of the slope B as the calculation factor for sample measurement. 6.2.3 Determine the correction factor
Use the single-point correction method to calculate the correction factor. Take a standard gas with a concentration of carbon disulfide close to that in the sample air, operate according to 6.2.2, measure the average peak height (mm) and retention time of the chromatographic peak, and calculate the correction factor f according to formula (3). f=
Where:
Correction factor,
-logarithm of standard gas concentration,
Igh-logarithm of average peak height.
（3）
GB 11741—89
6.3 Sample determination
Take 5mL of air sample and inject it into the chromatograph. According to the operation in 6.2.2, use the retention time for qualitative analysis and measure the peak height of carbon disulfide. Perform three times for each sample and calculate the average peak height. Record the air temperature and atmospheric pressure during the analysis. High-concentration samples should be diluted to less than 12mg/m2 with clean air and then analyzed.
? Result calculation
7.1 Standard curve method Use formula (4) to calculate the carbon disulfide concentration. Igc=Igh×Be
Where: Igc
~The logarithm of the carbon disulfide concentration in the sample air. Then find the antilogarithm to get the concentration value (mg/m2), - the logarithm of the average peak height of carbon disulfide in the sample air, B--the calculation factor obtained in 6.2.2.
7.2 Calculate the concentration using the correction factor according to formula (5). Igc = Igh × f.
Where: Igc
The logarithm of the carbon disulfide concentration in the sample air. The antilogarithm is then used to obtain the concentration value (mg/m3), the logarithm of the average value of the carbon disulfide peak height in the sample air, and the correction factor obtained from 6.2.3.
7.3 Use formula (6) to convert to the concentration under standard conditions. c=cx
Where: co-
The carbon disulfide concentration in the air under standard conditions, mg/m3, ~Absolute temperature under standard conditions, 273K,
The air temperature during analysis,
P. --Atmospheric pressure under standard conditions, 101.3kPa, —The atmospheric pressure during analysis, kPa.
8 Precision and Accuracy
8.1 Reproducibility
The coefficient of variation of repeated determinations of carbon disulfide concentrations in the range of 0.08-0.68 mg/m3 is 9%-4%. 8.2 Recovery
The recovery of carbon disulfide concentrations in the range of 0.06-0.31 mg/m2 is 88%-102%. 530
（4）
（5）
A1 Chromatographic analysis conditions
Column box temperature: 88℃,
Detection chamber temperature: 120℃,
Vaporization chamber temperature: 120℃
GB 11741-89
Appendix A
Example of gas chromatography analysis of carbon disulfide in air (reference)
Photomultiplier tube DC high voltage: 650V,
Injection volume: 5mL,
Carrier gas: , 18mL/min,
Hydrogen: 110ml/min,
Air: 100mL/min
Recorder: full scale 10mV.
A2 The chromatogram obtained according to the chromatographic analysis conditions of A1 is shown in Figure A1. SO? cS.
1'15″2'25
Column temperature 75
Time, min
Chromatogram of each component
Column temperature 88 r
Time, min
GB 11741-89
Appendix B
Temperature and concentration of saturated vapor of carbon disulfide
(Supplement)
B1The relationship between temperature and concentration of saturated vapor of carbon disulfide is shown in Table B1. Table B1
t, ℃
dt, ng/mL
194.84 ×10 3
455.47×103
1621.52×103
The temperature and carbon disulfide saturated vapor concentration curve drawn using the data in Table B1 is shown in Figure B1. t,rl
Temperature and saturated vapor concentration curve
2902.49×103
dt , 10'ng /mL
Additional remarks:
This standard was proposed by the Health Supervision Department of the Ministry of Health. GB 11741-89
This standard was drafted by the Chengdu Municipal Health and Epidemic Prevention Station. The main drafter of this standard is Duan Weiming.
This standard was interpreted by the Environmental Health Monitoring Institute of the Chinese Academy of Preventive Medicine, the technical unit entrusted by the Ministry of Health. 533
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