HJ 504-2009_English: PDF (HJ504-2009)
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Ambient air. Determination of ozone. Indigo disulphonate spectrophotometry
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HJ 504-2009
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Standards related to: HJ 504-2009
| Standard ID | HJ 504-2009 (HJ504-2009) | | Description (Translated English) | Ambient air. Determination of ozone. Indigo disulphonate spectrophotometry | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z15 | | Classification of International Standard | 13.040 | | Word Count Estimation | 10,143 | | Date of Issue | 2009-10-20 | | Date of Implementation | 2009-12-01 | | Older Standard (superseded by this standard) | GB/T 15437-1995 | | Drafting Organization | Shenyang Municipal Environmental Monitoring Center Station | | Administrative Organization | Ministry of Environment Protection | | Regulation (derived from) | Department of Environmental Protection Notice No. 54 of 2009 | | Summary | This standard specifies the determination of ozone in ambient air indigo carmine spectrophotometry. This standard applies to the determination of ozone in ambient air. Relatively closed environment (such as indoor, interior, etc.) Determination of ozone in the air may also refer to this standard. |
HJ 504-2009
Ambient air.Determination of ozone.Indigo disulphonate spectrophotometry
HJ
National Environmental Protection Standard of the People's Republic
Replace GB/T 15437-1995
Determination of ambient air ozone
Indigo disulphonate spectrophotometry
Ambient air-Determination of ozone
-Indigo disulphonate spectrophotometry
Released on.2009-10-20
2009-12-01 Implementation
Ministry of Environmental Protection released
Ministry of Environmental Protection
announcement
No. 54 of.2009
In order to implement the "Environmental Protection Law of the People's Republic of China", protect the environment, and protect human health, we now approve the measurement of total organic carbon in water quality.
Six standards, such as the combustion oxidation-non-dispersive infrared absorption method, are national environmental protection standards and are released.
The standard name and number are as follows.
I. Determination of total organic carbon in water by combustion oxidation-non-dispersive infrared absorption method (HJ 501-2009);
2. Determination of brominated volume of volatile phenols in water (HJ 502-2009);
3. Determination of volatile phenols in water - 4-aminoantipyrine spectrophotometric method (HJ 503-2009);
V. “Determination of Biochemical Oxygen Demand (BOD5) on the 5th Day of Water Quality Dilution and Inoculation Method” (HJ 505-2009);
6. "Electrochemical Probe Method for Determination of Dissolved Oxygen in Water" (HJ 506-2009).
The above standards have been implemented since December 1,.2009 and published by the China Environmental Science Press. The standard content can be found on the website of the Ministry of Environmental Protection.
The following seven national rings approved and issued by the former National Environmental Protection Agency or the former State Environmental Protection Administration from the date of implementation of the above standards
The environmental protection standards are abolished. The standard names and numbers are as follows.
1. "Measurement of total organic carbon (TOC) for water quality by non-dispersive infrared absorption method" (GB 13193-91);
2. Determination of total organic carbon in water by combustion oxidation-non-dispersive infrared absorption method (HJ/T 71-2001);
3. Determination of volatile phenols in water quality and bromination capacity after distillation (GB 7491-87);
4. Determination of volatile phenols in water - 4-aminoantipyrine spectrophotometric method after distillation (GB 7490-87);
V. Determination of ozone in ambient air - Spectrophotometric method of sodium indigo disulphonate (GB/T 15437-1995);
6. "Determination of the Biochemical Oxygen Demand (BOD5) on the 5th Day of Water Quality Dilution and Inoculation Method" (GB 7488-87);
VII. Determination of Dissolved Oxygen in Water by Electrochemical Probe Method (GB 11913-89).
Special announcement.
October 20,.2009
Content
Foreword..iv
1 Scope..1
2 Method principle..1
3 reagents and materials.1
4 instruments and equipment. 2
5 samples. 2
6 Analysis steps..3
7 results indicate ..3
8 Accuracy and precision..3
9 Notes. 4
Appendix A (Normative) A standard curve is drawn using a known mass concentration of ozone standard gas..5
Foreword
To protect the environment and protect people in order to implement the Environmental Protection Law of the People's Republic of China and the Law of the People's Republic of China on the Prevention and Control of Air Pollution
This standard is formulated for the health of the body and the monitoring method for the regulation of ozone in the ambient air.
This standard specifies the indigo disulphonate spectrophotometric method for the determination of ozone in ambient air.
This standard is a revision of the "Measurement of ambient air ozone by indigo disulfonate spectrophotometry" (GB/T 15437-1995).
This standard was first published in.1995. The original drafting unit was the Shenyang Environmental Monitoring Center Station. This is the first revision.
The main contents of this revision are as follows.
-- Revised the scope of application of the standard, increasing the upper limit of measurement and the lower limit of measurement;
- modified the concentration of indigo disulphonate (IDS) absorption solution;
--Sampling two pairs of porous glass plate absorption tubes sampled into a single porous glass plate absorption tube sampling;
-- Added "field blank" in the sampling section;
-- Added "Precautions" clause;
-- "Draw a working curve with a known mass concentration of ozone standard gas" from the standard text to the appendix.
Since the date of implementation of the standard, the national environmental protection standard “Environmental Empty” approved and issued by the former National Environmental Protection Agency on March 25,.1995
Determination of gas ozone Determination of indigo disulfonate spectrophotometry (GB/T 15437-1995).
Appendix A of this standard is a normative appendix.
This standard is revised by the Science and Technology Standards Department of the Ministry of Environmental Protection.
This standard is mainly drafted by. Shenyang Environmental Monitoring Center Station.
This standard was approved by the Ministry of Environmental Protection on October 20,.2009.
This standard has been implemented since December 1,.2009.
This standard is interpreted by the Ministry of Environmental Protection.
Iv
Determination of ambient air ozone - Indigo disulfonate spectrophotometry
1 Scope of application
This standard specifies the indigo disulphonate spectrophotometric method for the determination of ozone in ambient air.
This standard applies to the determination of ozone in ambient air. Relatively closed environment (such as indoors, cars, etc.) can also be used to determine ozone in the air.
According to this standard.
When the sampling volume is 30 L, the detection limit of ozone in this standard is 0.010 mg/m3, and the lower limit of determination is 0.040 mg/m3.
When the sample volume is 30 L and the mass concentration of the solution is 2.5 μg/ml or 5.0 μg/ml, the upper limit of determination is 0.50 mg/m3 or
1.00 mg/m3. When the mass concentration of ozone in the air exceeds the upper limit, the sampling volume can be appropriately reduced.
2 Principle of the method
The ozone in the air reacts with the blue indigo disulphonate in the presence of a phosphate buffer solution in an equimolar amount to decolorize to form ruthenium.
Sodium red disulfonate, the absorbance is measured at 610 nm, and the concentration of ozone in the air is quantified according to the degree of blue decrease.
3 reagents and materials
Unless otherwise stated, the reagents used in this standard use analytical purification reagents that meet national standards, and experimental waters are newly prepared for removal.
Sub-water or distilled water.
3.1 Potassium bromate standard stock solution, c (1/6 KBrO3) = 0.100 0 mol/L. accurately weigh 1.391 8 g potassium bromide (excellent grade, 180 ° C baked
2 h), in a beaker, add a small amount of water to dissolve, transfer to a 500 ml volumetric flask, and dilute to the mark with water.
3.2 Potassium bromate-potassium bromide standard solution, c(1/6 KBrO5)= 0.010 0 mol/L. Pipette 10.00 ml Potassium bromate standard stock solution (3.1)
In a 100 ml volumetric flask, add 1.0 g of potassium bromide (KBr) and dilute to the mark with water.
3.3 sodium thiosulfate standard stock solution, c (Na2S2O3) = 0.100 0 mol/L.
3.4 sodium thiosulfate standard working solution, c (Na2S2O3) = 0.005 00 mol/L. before use, take sodium thiosulfate standard stock solution (3.3)
Dilute 20 times with water freshly boiled and cooled to room temperature.
3.5 sulfuric acid solution, 16.
3.6 Starch indicator solution, ρ = 2.0 g/L. Weigh 0.20 g of soluble starch, make a paste with a small amount of water, slowly pour into 100 ml of boiling water,
Boil until the solution is clear.
3.7 Phosphate buffer solution, c(KH2PO4-Na2HPO4)=0.050 mol/L. Weigh 6.8 g potassium dihydrogen phosphate (KH2PO4), 7.1 g
Disodium hydrogen phosphate (Na2HPO4), dissolved in water, diluted to 1 000 ml.
3.8 Indigo disulphonate (C16H8O8Na2S2) (IDS for short), analytically pure, chemically pure or biochemical reagents.
3.9 IDS standard stock solution. Weigh 0.25 g of sodium indigo disulphonate (3.8) dissolved in water and transfer to a 500 ml brown volumetric flask.
Dilute to the mark, shake well, and store in the dark at room temperature for 24 h and then calibrate. This solution can be stored in the dark at 20 ° C for 2 weeks.
Calibration method. Accurately absorb 20.00 ml IDS standard stock solution (3.9) in 250 ml iodine flask, add 20.00 ml bromic acid
Potassium-potassium bromide solution (3.2), add 50 ml of water, cover the stopper, and place in a 16 ° C ± 1 ° C biochemical incubator (or water bath) to the solution
When the temperature is balanced with the bath temperature [Note 1], add 5.0 ml of sulfuric acid solution (3.5), immediately cover, mix and start timing, dark at 16 °C ± 1 °C
After placing for 35 min ± 1.0 min, add 1.0 g of potassium iodide, immediately cover it, gently shake until dissolved, and place it in the dark for 5 min.
The sodium solution (3.4) is titrated until the brown color just fades to a pale yellow color. Add 5 ml of starch indicator solution (3.6) and continue titration to blue.
Retreat, the end point is bright yellow. Record the volume of sodium thiosulfate standard working solution (3.4) consumed [Note 2].
Note 1. The time to reach equilibrium is related to the temperature difference. You can replace the solution with the same volume of water in advance, add it to the iodine bottle, and put it into the thermometer to observe the balance.
The time required.
Note 2. The volume of sodium thiosulfate standard solution consumed by parallel titration should not be 0.10 ml larger.
The mass concentration of ρ (μg/ml) equivalent to ozone per milliliter of indigo disulphonate solution is calculated by formula (1).
ρ = 1 1 2 2c V c V
×12.00×103 (1)
Where. ρ - per ml of indigo disulphonate solution equivalent to the mass concentration of ozone, μg/ml;
C1--potassium bromate-potassium bromide standard solution (3.2) concentration, mol/L;
V1--volume of potassium bromate-potassium bromide standard solution, ml;
C2--concentration of sodium thiosulfate standard solution used for titration, mol/L;
V2--the volume of sodium thiosulfate standard solution used for titration, ml;
V--IDS standard stock solution (3.9) volume, ml;
12.00 - molar mass of ozone (1/4 O3), g/mol.
3.10 IDS Standard Working Solution. Dilute the calibrated IDS standard stock solution (3.9) with phosphate buffer solution (3.7) step by step.
ML is equivalent to 1.00 μg ozone of IDS standard working solution, which can be stored in the dark at 20 ° C for 1 week.
3.11 IDS Absorbent. Take appropriate amount of IDS standard stock solution (3.9), dissolve with phosphate buffer according to the concentration of ozone in the air.
Dilute the liquid (3.7) to an equivalent of 2.5 μg (or 5.0 μg) of ozone per ml of ozone. This solution can be stored in the dark below 20 °C.
Months.
4 Instruments and equipment
Unless otherwise stated, this standard uses glass gauges that meet national Class A standards.
4.1 Air sampler. The flow range is 0.0~1.0 L/min, and the flow rate is stable. When using, use a soap membrane flowmeter to calibrate the sampling system before sampling.
And the measured flow rate, the relative error should be less than ± 5%.
4.2 Porous glass plate absorption tube. 10 ml of absorption liquid is contained inside, and gas is collected at a flow rate of 0.50 L/min. The resistance of the glass plate should be 4 to 5 kPa.
Disperse evenly.
4.3 with colorimetric tube. 10 ml.
4.4 Biochemical incubator or constant temperature water bath. temperature control accuracy is ±1 °C.
4.5 Mercury thermometer. Accuracy is ±0.5 °C.
4.6 Spectrophotometer. With a 20 mm cuvette, the absorbance can be measured at a wavelength of 610 nm.
4.7 Glass instruments commonly used in general laboratories.
5 samples
5.1 Sample collection and preservation
Use a porous glass plate absorber tube containing 10.00 ml ± 0.02 ml IDS absorbing solution (3.11), cover with black light shield and flow at 0.5 L/min
The amount of gas is 5 to 30 L. When the absorbing solution fades by about 60% (compared to the blank sample in the field), sampling should be stopped immediately. Samples are transported and stored
It should be strictly protected from light during the release process. When you are sure that the mass concentration of ozone in the air is low and will not penetrate, you can use a brown glass plate to absorb the tube sampling.
Store samples in a dark place at room temperature for at least 3 days.
5.2 Field blank sample
Use the same batch of IDS absorbent (3.11), put it into the absorption tube of the porous glass plate, and bring it to the sampling site. Except for not collecting air samples
Outside the product, the other environmental conditions remain the same as the sampling tube for collecting air.
At least two field blank samples are taken for each batch of samples.
6 Analysis steps
6.1 Drawing a calibration curve
6.1.1 Take 10 ml plugs with 6 colorimetric tubes and prepare standard color columns according to Table 1.
Table 1 standard color column
Pipe number 1 2 3 4 5 6
IDS standard solution (3.10)/ml 10.00 8.00 6.00 4.00 2.00 0.00
Phosphate buffer solution (3.7)/ml 0.00 2.00 4.00 6.00 8.00 10.0
Ozone mass concentration/(μg/ml) 0.00 0.20 0.40 0.60 0.80 1.00
6.1.2 Shake each tube and measure the absorbance at a wavelength of 610 nm using a 20 mm cuvette with water as a reference. To zero concentration in the calibration series
The difference between the absorbance (A0) of the tube and the absorbance (A) of each standard tube is the ordinate, and the ozone concentration is the abscissa.
Multiplication calculates the regression equation of the calibration curve.
y = bx a
Where. y--A0−A, the difference between the absorbance of the blank sample and the absorbance of each standard color tube;
x--Ozone mass concentration, μg/ml;
B--the slope of the regression equation, absorbance·ml/μg;
A--the intercept of the regression equation.
6.2 Drawing a standard working curve with a known mass concentration of ozone standard gas
When using this method as the secondary transfer standard for the UV ozone analyzer, draw the standard work piece with the known mass concentration of ozone standard gas.
For details, see Appendix A of this standard.
6.3 Sample determination
After sampling, a glass tip is connected in series at the inlet end of the absorption tube, and the suction port is pressurized at the outlet end of the absorption tube to be in the absorption tube.
Transfer the sample solution to a 25 ml (or 50 ml) volumetric flask and wash the tube several times with water to a total volume of 25.0 ml (or 50.0 ml).
The absorbance was measured at a wavelength of 610 nm using a 20 mm cuvette with water as a reference.
7 results indicate
The mass concentration of ozone in the air is calculated according to formula (2).
ρ (O3)= 0
( )AA a V
b V
− − ×
× (2)
Where. ρ (O3)--the mass concentration of ozone in the air, mg/m3;
A0--the average value of the absorbance of the blank sample (5.2) in the field;
A--the absorbance of the sample;
B--the slope of the standard curve;
A--the intercept of the standard curve;
V--the total volume of the sample solution, ml;
V0--Sampling volume converted to standard state (101.325 kPa, 273 K), L.
The results are accurate to three decimal places.
8 Accuracy and precision
The slopes of the six laboratory IDS standard curves ranged from 0.863 to 0.935 with an average of 0.899.
Six laboratories measured three quality concentration levels of IDS standard solution from 0.085 to 0.918 mg/L, and repeated measurement at each concentration level.
Set 6 times, the repeatability precision is ≤0.004 mg/L, and the reproducibility precision is ≤0.030 mg/L.
Six laboratories measured ozone standard gas with a mass concentration ranging from 0.088 to 0.946 mg/m3, and the repeatability coefficient of variation was less than
10%, the relative error is less than ± 5%.
9 Precautions
9.1 Interference
Nitrogen dioxide in the air can make the determination of ozone higher, about 6% of the mass concentration of nitrogen dioxide.
The mass concentration of sulfur dioxide, hydrogen sulfide, peroxyacetyl nitrate (PAN) and hydrogen fluoride in the air is higher than 750 μg/m3, respectively.
Interference with ozone at 110 μg/m3, 1 800 μg/m3 and 2.5 μg/m3.
The presence of chlorine and chlorine dioxide in the air makes the measurement of ozone higher. But in general, the concentration of these gases is very low, not
Will cause significant errors.
9.2 IDS standard solution calibration
Commercially available IDS is not pure and must be calibrated when used as a standard solution. Calibrate the IDS reaction with potassium bromate-potassium bromide standard solution,
It needs to be carried out under acidic conditions. The reaction starts after the addition of the sulfuric acid solution, and the reaction is terminated after the addition of potassium iodide. In order to avoid side reactions
Quantitatively, the incubator (or water bath) temperature (16 ° C ± 1 ° C) and reaction time (35 min ± 1.0 min) must be strictly controlled. Be sure to wait
Add the sulfuric acid solution (3.5) when the temperature of the solution reaches equilibrium with the temperature of the incubator (or water bath), and immediately cover the solution after adding the sulfuric acid solution.
And start timing. Sunlight should be avoided during the titration.
9.3 IDS absorption volume
The method is a fading reaction, and the volume of the absorbing liquid directly affects the accuracy of the measurement, so the volume of the absorbing liquid charged into the sampling tube must be accurate.
Indeed, it is best to add with a pipette. After the sample is transferred to the volumetric flask, the absorption liquid should be as complete as possible (small number of rinses). Picking fluid
The sample tube should be prevented from tilting or inverting during transportation, storage and pick-and-place to avoid loss of absorption liquid.
Appendix A
(normative appendix)
Draw a standard curve with a known mass concentration of ozone standard gas
A.1 instrument
A.1.1 Ozone generator
A.1.2 Gas distribution device
A.1.3 Primary UV calibration photometer or UV ozone analyzer
A.2 Drawing of standard curve
Preparing at least four different mass concentrations in a mass concentration range of 0.05 to 1.000 mg/m3 by means of an ozone generator and a gas distribution device
The ozone standard gas, the standard gas concentration is measured by a first-order ultraviolet calibration photometer or by a first-standard calibrated ultraviolet ozone analyzer.
set. At the same time, use IDS absorption liquid to collect ozone standard gas of different mass concentration according to 5.1 of this standard, and absorb the light of the sample according to 6.3 of this standard.
degree. Taking the ozone mass concentration as the abscissa, the absorbance (A0) of the blank sample in the field and the absorbance of the standard gas of different mass concentrations (A)
The difference is the ordinate, and the regression equation of the standard curve is calculated by the least squares method.
y bx a=
Where. y--A0−A, the difference between the absorbance of the blank sample in the field and the absorbance of the standard gas samples of different concentrations;
X--the mass concentration of ozone, μg/ml;
B--the slope of the regression equation;
A--the intercept of the regression equation.
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