This standard specifies the determination of sulfate concentration in residential atmosphere by ion chromatography. This standard applies to the determination of sulfate concentration in residential atmosphere. GB/T 11733-1989 Standard method for the determination of sulfate in residential atmosphere Ion chromatography GB/T11733-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Sanitary examination of inorganic sulfate in air of residential areas
Standard method Ion chromatography
Standard method for hygienic examinationof inorganic sulfate in air of residential areas --Ion-chromatography1 Subject content and scope of application
This standard specifies the determination of sulfate concentration in the atmosphere of residential areas by ion chromatography. This standard is applicable to the determination of sulfate concentration in the atmosphere of residential areas. 1.1 Detection limit
GB 11733-89
The detection limit is 0.5μg/mL. When the sampling volume is 600L, the minimum detection concentration is 0.008mg/m3. 1.2 Determination range
The determination range is 0.5～50μg/mL. When the sampling volume is 600L, the determination range is 0.008～0.8mg／m3. 1.3 Interference and elimination
1.3.1 Due to the use of chromatographic separation technology, there is no interference from sulfur dioxide and nitrogen oxides, but the interference with sulfuric acid mist can be eliminated by isopropanol-anhydrous ethanol.
1.3.2 After sampling, put it in a dryer and balance for more than 6 hours to eliminate the influence of humidity on this method. 2 Principle
Sulfate particles in the air are collected by the filter membrane, and sulfuric acid mist is removed by isopropanol-anhydrous ethanol. Then, the sulfate in the sample is dissolved by the eluent and determined by ion chromatography. Retention time is used for qualitative analysis and peak height is used for quantitative analysis. 3 Reagents and materials
3.1 Deionized water: deionized water with a conductivity lower than 1.0μS/cm. 3.2 Synthetic fiber filter membrane: Φ40mm.
3.3 Anhydrous ethanol: analytical grade.
3.4 ​​Iso-lactone: analytical grade.
3.5 Anhydrous sodium carbonate: superior grade.
3.6 Anhydrous sodium bicarbonate: superior grade.
3.7 Potassium chromate: analytical grade.
3.8 Eluent (l): 0.24mol/LNa2CO3-0.3mol/LNaHCO, for eluent reserve solution. Take 10.0mL each in a 1L volumetric flask and add water to the mark before use. This solution is used for the ion chromatograph with conductivity detector. 3.9 Eluent (III): 2×10~2mol/L potassium chromate solution is the eluent reserve solution. Take 10.0mL in a 1L volumetric flask before use and add water to the mark before use. This solution is used for the ion chromatograph with visible spectrophotometer detector. 3.10 Standard solution: accurately weigh 1.4786g of anhydrous sodium sulfate or 1.8141g of anhydrous potassium sulfate that has been dried at 105℃ for 2h and dissolve in a small amount of water, transfer to a 1L container, and dilute to the mark with water. This solution is 1.00mL of standard solution containing 1mg of sulfate. Approved by the Ministry of Health of the People's Republic of China on September 21, 1989 492bzxZ.net
Implementation on July 1, 1990
4 Instruments and equipment
4.1G4 glass sand core funnel: inner diameter 40mm. 4.2 Stoppered colorimetric tube: 25mL.
4.3 Syringe: 1.0mL.
4.4 Beaker: 50mL.
4.5 Electric aspirator: with suction bottle and suction rubber pad. 4.6 Constant temperature water bath: temperature control accuracy ±0.5℃. GB 11733-89
4.7 Ion chromatograph: with conductivity detector or visible light spectrophotometer. 4.8 Sampler: flow range is 5~30L/min, flow is stable, when in use, use soap film flowmeter to calibrate the flow of the sampling series before and after sampling. The flow error should be less than 5%. 5 Sampling
Put the dried synthetic fiber filter membrane with a diameter of 40mm flat on the sampling clamp and clamp it. Sampling 600L at a flow rate of 20~28L/min. After sampling, carefully remove the sampling filter membrane, fold it inward, and still put it in the box of the original sampling filter membrane, store it in a desiccator, and record the air temperature and atmospheric pressure at the time of sampling.
6 Analysis steps
6.1 Chromatographic analysis conditions
Since the chromatographic analysis conditions are different, the best ion chromatography analysis conditions for analyzing sulfate should be formulated according to the model of the ion chromatograph used and the performance of the detector. The ion chromatography analysis conditions listed in Appendix A (reference) are an example. 6.2 Drawing the standard curve and determining the correction factor Under the same conditions as the sample analysis, draw the standard curve or determine the correction factor. 6.2.1 Drawing the standard curve
Use the eluent to dilute the sulfate standard solution into 0, 2.5, 5.0, 10, 20, 30, 40, 50μg/mL standard solutions, respectively. Use a 1.0mL syringe to take the standard solution of each concentration and inject it into the ion chromatograph to obtain the chromatographic peak and retention time of each concentration. Each concentration is measured three times, and the average value of the peak height (mm) is measured. Draw the standard curve with the sulfate concentration (μg/mL) as the horizontal axis and the peak height (mm) as the vertical axis. And calculate the residual slope of the regression line, and use the reciprocal of the slope (Bsμg/(mL·mm)) as the calculation factor for sample determination.
6.2.2 Determination of the correction factor
When the stability of the instrument is poor, the correction factor can be obtained by the single-point calibration method. While the sample is being measured, use a 1.0 mL syringe to take a zero concentration and a standard solution with a concentration close to that of sulfate in the sample solution, respectively. According to the operation in 6.2.1, measure the average chromatographic peak height (mm) and retention time of the zero concentration and the standard solution. Use formula (1) to calculate the correction factor. f
Formula t: f—correction factor f, μg/(mL·mm), Co—concentration of the standard solution, μg/mL; co
h. and hs—average peak height of the zero concentration and the standard solution, mm. 6.3 Sample determination
...(1)
6.3.1 Sample treatment
Use tweezers to take the sample and the blank filter membrane, dust side up, half-flatten them in a 50 mL beaker, add 10 mL of isopropanol and soak for 2 to 3 hours, take out the flat sand core funnel, pour all the isopropanol into the funnel, filter by suction, discard the filtrate, and wash with 10 mL of anhydrous ethanol three times to remove the sulfuric acid mist on the sample. Then cut the filter membrane radially. Place it in a 25mL colorimetric tube, add 10mL of eluent, cover and shake, place in a 65C constant temperature water bath for elution for 30min, and take the supernatant for determination. 493
GB 11733--89
Take two unsampled filter membranes and prepare two blank solutions in the same way as the sample filter membranes. 6.3.2 Sample analysis
While drawing the standard curve or determining the correction factor, use a 1.0mL syringe to draw the blank and sample solutions respectively, and inject them into the ion chromatograph in sequence under the same working conditions to obtain the chromatographic peaks. Qualitative analysis based on retention time. Do it three times each, and measure the average value (mm) of the blank and sample peak heights.
7 Result calculation
7.1 Convert the sampling volume into the sampling volume under standard conditions using formula (2). Vo=Vtx
Where: V.
Converted to the sampling volume under standard conditions, L, - obtained by multiplying the sampling flow rate by the sampling time, L absolute temperature under standard conditions, 273K, temperature at the sampling point during sampling, ℃,
Atmospheric pressure under standard conditions, 101.3kPa, po -
The maximum pressure at the sampling point during sampling, kPa.
1+ 273
7.2 Standard curve method Use formula (3) to calculate the mass concentration of sulfate in the air. C
Where: ℃ -
~Mass concentration of sulfate in the air, mg/m3, Average peak height of the sample solution, mm,
h. -Average peak height of the blank solution, mm, × Bs×10
BsCalculation factor obtained from 6.2.1, μg/(mL·mm) -Elution efficiency determined by experiment,
-Total volume of sample solution, mL,
- Sampling volume under standard conditions, L
7.3 Use the correction factor to calculate the mass concentration of sulfate in the air according to formula (4): c
(h-ho)f
V. ·E
Where: f—correction factor obtained from 6.2.2, μg! (mL·mm); other symbols are shown in 7.2.
Precision and accuracy
8.1 Reproducibility
Add 50ug of sulfate solution to the filter membrane and repeat the measurement 17 times. The coefficient of variation is 4.6%. 8.2 Recovery rate
Add 50μg of sulfate solution to the filter membrane, and the average recovery rate is 98%. 194
(2)
(3)
GB11733-89
Appendix A
Example of analytical conditions for analyzing sulfate in air by ion chromatography (reference)
Use ion chromatography conductivity identification device, select YSA-2 type anion separation column and pre-column. Column pressure drop <40kg/cm2, YS2 type cation suppression column, column pressure drop <4kg/cm2. Instrument setting temperature 30±0.5℃, sensitivity 5, attenuation 16, eluent flow 3.0mL／min, recorder full scale 1.0mV, paper speed 0.05mm/s, separation column inner diameter 4×330mm. Additional remarks:
This standard is proposed by the Health Supervision Department of the Ministry of Health. This standard was drafted by the Hebei Provincial Health and Epidemic Prevention Station, the Environmental Health Monitoring Institute of the Chinese Academy of Preventive Medicine, and the Yangzhou Health and Epidemic Prevention Station. The main drafters of this standard are Pang Lianque and He Jianwei. This standard is interpreted by the Environmental Health Monitoring Institute of the Chinese Academy of Preventive Medicine, the technical unit entrusted by the Ministry of Health.
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