GB/T 11735-1989 Standard method for the examination of beryllium in the atmosphere of residential areas - Morin fluorescence spectrophotometry

This standard specifies the determination of beryllium concentration in residential atmosphere by morin fluorescence spectrophotometry. This standard applies to the determination of beryllium concentration in residential atmosphere. GB/T 11735-1989 Standard method for the sanitary examination of beryllium in residential atmosphere Morin fluorescence spectrophotometry GB/T11735-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Standard method for hygienic examination ofberyllium in air of residential areas-Morinfluorescence spectrophotometric method
Standard method for hygienic examination ofberyllium in air of residential areas-Morinfluorescence spectrophotometric method 1 Subject content and scope of application
This standard specifies the determination of beryllium concentration in air of residential areas by morinfluorescence spectrophotometric method. This standard is applicable to the determination of beryllium concentration in air of residential areas. 1.1 Sensitivity
The fluorescence intensity of 0.054±0.002 should be 0.01μg beryllium in a 10mL measurement volume. GB 11735-89
1.2 Lower limit of detection
The lower limit of detection is 0.01μg/10mL. If the sampling volume is 3m3, the minimum detection concentration is 0.003μg/m3. 1.3 Measurement range
The measurement range is 0.01~0.1μg beryllium in 10mL solution. If the sampling volume is 3m3, the measurable concentration range is 0.003~0.033 μg/m2.
1.4 Interference and Elimination
Effective measures have been taken to eliminate various known interferences in this method, among which cations such as A13+, Cd2, and Zn2 are complexed with EDTA. Fe3° and Mn2 are masked with triethanolamine, and sodium sulfite is added to prevent the oxidation of morin itself. 2 Principle
The beryllium and its compounds collected on the filter membrane are dissolved with acid. In an alkaline medium, the complex formed by the reaction of beryllium ions and morin produces yellow-green fluorescence under ultraviolet irradiation. Quantification is carried out according to the fluorescence intensity. 3 Reagents and Materials
Except for the masking agent, which is analytically pure, all other reagents used in this method are of high purity; water is double distilled water. 3.1 Polyvinyl chloride filter membrane: diameter 40mm.
3.2 Mixed acid: 1 part sulfuric acid mixed with 5 parts nitric acid. 3.3 Digestive solution: 1 part perchloric acid mixed with 1 part nitric acid. 3.4 Hydrochloric acid.
3.5 0.1mol/L hydrochloric acid solution: 8.2mL hydrochloric acid diluted to 1L with water. 3.6 0.6mol/L sodium hydroxide solution: 24g sodium hydroxide dissolved in 1L water. 3.7 Masking agent: 5.0g disodium ethylenediaminetetraacetic acid and 1.0g sodium bisulfite dissolved in 100mL water, add 1.0mL 75% triethanolamine solution, mix well.
3.8 Congo red test paper (color change range [pH3.0～5.2]. 3.9 Morin ethyl ketone solution.
3.9.1 0.05% Morin stock solution: weigh 50 mg Morin [purification method see Appendix A (supplement), dissolve in 95% ethanol, approved by the Ministry of Health of the People's Republic of China on September 21, 1989 500
1990-07-01 implementation
GB11735-89
transfer to a 100mL brown volumetric flask, and dilute to the mark with 95% ethanol, put in the refrigerator, stable for ~ months. 3.9.2 0.005% Morin working solution: before use, take the stock solution and dilute it 10 times with 95% ethanol. 3.10 Standard solution.
3.10.1 Standard stock solution: accurately weigh 0.1968g beryllium sulfate (BeSO4·4H2O) , dissolve with water, add 50mL hydrochloric acid and transfer to 1L volumetric flask t1, add water to the mark. This solution contains 10μg beryllium in 1.00mL. 3.10.2 Standard solution: When used, dilute the stock solution with 0.5% hydrochloric acid solution to 1.00mL standard solution containing 0.1μg beryllium. 4 Instruments and equipment
4.1 Filter material sampling clip: Made of inert material (such as polyvinyl chloride or polystyrene), with an effective gas sampling surface diameter of 30mm. 4.2 Inhalable particle sampler: Sampler for collecting particles in the air with a particle size of less than 10μm. Population requirements: D,3=10±1μm, 82=1.5±0.1. The flow rate is stable and can be continuously sampled for more than 24h. The flow error should be less than 5%. Note: 1) Ds 0——median diameter of particles. 2)ag-Www.bzxZ.net
-geometric standard deviation.
Electric constant temperature water bath.
4.4 Stoppered colorimetric tube: 10mL.
4.5 Fluorescence spectrophotometer.
5 Sampling
Place the polyvinyl chloride filter on the sampling clamp, clamp it, and collect 3m3 of air sample according to the flow rate specified by the sampler. At the same time, record the temperature and atmospheric pressure during sampling. After sampling, carefully remove the filter membrane, fold it in half with the dust side facing inward, put it in a clean paper bag, and then put it in the sample box for storage.
6 Analysis steps
6.1 Drawing of standard curve.
6.1.1 Take 6 10mL stoppered colorimetric tubes and prepare standard color column tubes according to the table below. Standard color column tube
Standard solution, mL
Wrinkle containing missing,
6.1.2 Add 1mL of masking agent to each tube, put a small piece of Congo red test paper, adjust with 0.6mol/L sodium hydroxide solution until the test paper turns red, then add 1mL0.6mol/L sodium hydroxide solution, shake well, add 0.50mL of morin 1 as liquid, dilute with water to 10mL, shake well, keep constant temperature in 25±1 (water bath for 15min, on the fluorescence spectrophotometer, use 10mm quartz colorimetric IIIl, at the excitation light wavelength of 430nm, slit width of 8nm, emission light wavelength of 530nm, slit width of 3nm, with water as reference, measure the carbon light intensity of each tube solution. Take the beryllium content (g) as the horizontal axis and the fluorescence intensity as the vertical axis. Use the coordinates to draw the standard curve and calculate the slope of the Huizhou line. The reciprocal of the residual slope is used as the calculation factor B for sample determination: (μg/fluorescence intensity). 6.2 Sample determination
Use bright and rust-free scissors to cut the sampled filter membrane into small pieces and place them in a 100mL conical flask. Add 10mL of mixed acid and place a small glass funnel on the mouth of the flask. Heat on a hand-held hot plate until the filter membrane is completely carbonized. Continue heating for 5 minutes. Remove the flask and cool to room temperature. Add 3-5mL of digestion solution and continue heating until the solution is clear (if the carbon is not completely removed, add appropriate amount of digestion solution). Remove the funnel and evaporate the solution to nearly f, then remove and cool. Add 3mL of 0.1mol/L hydrochloric acid solution along the wall of the bottle, dissolve the residue with slight heat, and transfer to 501
GB 11735—89
Put the sample into a 10mL colorimetric tube, then wash the flask twice with 2mL of water, combine to make the total volume 5mL, and measure the fluorescence intensity of the sample solution according to the operating steps for making the standard curve (6.1.2). While measuring each batch of samples, use the unsampled filter membrane as a reagent blank. 7 Result calculation
71Use formula (1) to convert the sampling volume into the sampling volume under standard conditions. Vo=Vt×
Sampling volume under standard conditions, L,
Formula ti: Vo-
273 +t
-Sampling volume, obtained by multiplying the sampling flow rate by the sampling time, L, Vt
T. ---Absolute temperature under standard conditions, 273 K, the air temperature at the sampling location at the time of sampling, °C, the atmospheric pressure under standard conditions, 101.3 kPapo
the atmospheric pressure at the sampling location at the time of sampling, kPa. 7.2 The concentration of beryllium in air is calculated according to formula (2). C=
the concentration of beryllium in air, mg/m2,
where: c—
A—the fluorescence intensity of the sample solution;
Ao——the fluorescence intensity of the blank solution;
(A-Ao)Bs
B,—the calculation factor obtained from 6.1.2, microgram/fluorescence intensity. 8 Precision and Accuracy
8.1 Reproducibility
0.010, 0.050 and 0.100 μg of standard beryllium are added to the blank filter membrane, and the coefficients of variation of repeated measurements are 10%, 8% and 6% respectively. 8.2 Recovery rate
The beryllium content is 0.010, 0.050 and 0.100μg of the standard was added to the blank filter membrane for recovery experiment, and the recovery rate was 86-114%. 502
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Appendix A
Purification of Morin
(Supplement)
Take 10g of morin and dissolve it in a small amount of anhydrous ethanol, then add an equal volume of water to precipitate the morin crystals again, filter, and purify the precipitated morin again according to the above operation, then dissolve the precipitated morin in 30mL90% acetic acid, heat to boiling, cool slightly, add 20mL hydrobromic acid, filter with a sand core funnel, wash with a small amount of 90% acetic acid, wash with water until neutral, and dry at 105℃ for ten times until constant weight.
Additional remarks:
This standard was proposed by the Health Supervision Department of the Ministry of Health. This standard was drafted by the Hunan Institute of Labor Hygiene and the Guizhou Environmental Hygiene Monitoring Station. The main drafters of this standard are Chen Guiyi, Tang Limin, Dai Minci and Liu Changgeng. The Ministry of Health has entrusted the Institute of Environmental Health Monitoring, Chinese Academy of Preventive Medicine, to be responsible for the interpretation of this standard.
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