HJ 604-2017_English: PDF (HJ604-2017)
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivered in | Standard Title (Description) | Status | PDF |
| HJ 604-2017 | English | 249 |
Add to Cart
|
3 days [Need to translate]
|
Ambient air - Determination of total hydrocarbons, total methane and non-methane hydrocarbons - Direct injection / gas chromatography
| Valid |
HJ 604-2017
|
| HJ 604-2011 | English | 439 |
Add to Cart
|
3 days [Need to translate]
|
Ambient air. Determination of total hydrocarbons. Gas chromatographic method
| Obsolete |
HJ 604-2011
|
| Standard ID | HJ 604-2017 (HJ604-2017) | | Description (Translated English) | Ambient air - Determination of total hydrocarbons, total methane and non-methane hydrocarbons - Direct injection / gas chromatography | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z15 | | Classification of International Standard | 13.040.20 | | Word Count Estimation | 10,184 | | Date of Issue | 2017-12-14 | | Date of Implementation | 2018-03-01 | | Older Standard (superseded by this standard) | HJ 604-2011 | | Quoted Standard | HJ 194; HJ 664; HJ 732; HJ/T 55 | | Drafting Organization | Changzhou Environmental Monitoring Center | | Administrative Organization | Ministry of Environmental Protection | | Regulation (derived from) | Ministry of Environmental Protection Bulletin 2017 No. 71 | | Summary | This standard specifies direct gas chromatography for the determination of total hydrocarbons, methane, and non-methane total hydrocarbons in ambient air. This standard applies to the determination of total hydrocarbons, methane, and non-methane hydrocarbons in the ambient air, and also applies to the determination of total hydrocarbons, methane, and non-methane hydrocarbons in the air at the monitoring points of fugitive sources of pollution sources. When the injection volume is 1.0 ml, the detection limit of total hydrocarbons and methane measured in this standard is 0.06 mg/m^(3) (based on methane), and the lower limit of determination is 0.24 mg/m^(3) ( Methane); The detection limit of non-methane total hydrocarbons was 0.07 mg/m^(3) (in terms of carbon) and the lower limit of determination was 0.28 mg/m^(3) (in terms of carbon). |
HJ 604-2017
(Ambient air - Determination of total hydrocarbons, total methane and non - methane hydrocarbons - Direct injection - gas chromatography)
People's Republic of China national environmental protection standards
Total ambient air hydrocarbons, total methane and non-methane hydrocarbons
Determination of direct injection - gas chromatography
Ambient air-Determination of total hydrocarbons, methane and
nonmethane hydrocarbons-Direct injection/Gas chromatography
2017-12-14 Published
2018-03-01 implementation
Ministry of Environmental Protection released
Replacing HJ 604-2011
i directory
Foreword ..i
1 scope of application .1
2 Normative references .1
3 Terms and definitions .1
4 method principle .1
5 Reagents and materials .2
6 instruments and equipment .2
7 samples .2
8 Analysis steps .3
9 results calculated and said .5
10 precision and accuracy 5
11 Quality Assurance and Quality Control .6
12 Matters needing attention 6
i Foreword
In order to implement the Law of the People's Republic of China on Environmental Protection and the Law of the People's Republic of China on Prevention and Control of Atmospheric Pollution,
Habitat to protect human health, regulate the total ambient air hydrocarbons, methane and non-methane total hydrocarbon determination, the development of this standard.
This standard specifies the direct injection of gas, methane and non-methane hydrocarbon determination of ambient air - gas chromatography.
This standard is the "total ambient air hydrocarbons Determination of gas chromatography" (HJ 604-2011) revision.
This standard was first published in.1994, the original standard (GB/T 15263-1994) drafting unit for environmental monitoring in Gansu Province
Heart station, first revised in.2011. This is the second revision, the main contents of the revision are as follows.
- Expanded the determination of indicators, an increase of methane and non-methane total hydrocarbons, the corresponding revision of the standard name;
- Scope of application Increased measurement of total hydrocarbons, total methane and non-methane hydrocarbons in the air at monitoring points without organized discharges;
- revised the definition of total hydrocarbons and added the definition of non-methane total hydrocarbons;
- Increase the air bag as a sampling container, provides for sample collection, preservation methods and shelf life;
- Added quality assurance and quality control requirements;
- The appendix was deleted.
From the date of the implementation of this standard, "Determination of total hydrocarbons in ambient air by gas chromatography" (HJ 604-2011) abolished.
This standard by the Environmental Protection Department of Environmental Monitoring Division and Science and Technology Standards Division to develop.
This standard was drafted. Changzhou City Environmental Monitoring Center.
This standard verification unit. Jiangsu Province Environmental Monitoring Center, Suzhou City Environmental Monitoring Center Station, Suzhou Industrial Park Environmental Supervision
Center Station, Taizhou City Environmental Monitoring Center Station, Nantong City Environmental Monitoring Center Station, Zhenjiang City Environmental Monitoring Center Station and Changzhou
Wujin District Environmental Monitoring Station.
This standard MEP approved on December 14,.2017.
This standard since March 1,.2018 into effect.
This standard is interpreted by the MEP.
1 Ambient air Determination of total hydrocarbons, methane and non-methane hydrocarbons
Direct injection - gas chromatography
1 scope of application
This standard specifies the direct injection of gas, methane and non-methane hydrocarbon determination of ambient air - gas chromatography.
This standard applies to the determination of total hydrocarbons, methane and non-methane total hydrocarbons in ambient air, also applies to unorganized emission sources
Air and air - Determination of total hydrocarbons, methane and non - methane hydrocarbons in monitoring air.
When the injection volume is 1.0 ml, the total hydrocarbons measured in this standard, the detection limit of methane are 0.06 mg/m3 (in terms of methane),
The lower limit of determination was 0.24 mg/m3 (in terms of methane). The detection limit of total non-methane hydrocarbons was 0.07 mg/m3 (measured by carbon)
The lower limit is 0.28 mg/m3 (based on carbon).
2 Normative references
This standard references the following documents or the terms. For undated references, the effective version applies to this book
standard.
HJ 194 Manual Air Quality Monitoring Technical Specifications
HJ 664 Technical Specifications for Ambient Air Quality Monitoring Sites (Trial Implementation)
HJ 732 Fixed polluting sources - Volatile organic compounds - Sampling airbag method
HJ/T 55 Guidelines for Unorganized Emissions Monitoring of Air Pollutants
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Total hydrocarbons total hydrocarbons (THC)
Refers to the determination of the standard conditions, the gas chromatograph flame ionization detector has a response to the gas
The sum of machine compounds.
3.2
Non-methane total hydrocarbons nonmethane hydrocarbons (NMHC)
Refers to the total mercury content of other gaseous organic compounds after the methane is deducted from the total hydrocarbons
Unless otherwise stated, the result is in terms of carbon).
4 method principle
Gas samples were injected directly into a gas chromatograph with a hydrogen flame ionization detector, respectively on a total hydrocarbon column and a methane column
2 set total hydrocarbons and methane content, the difference between the two non-methane total hydrocarbon content. In the meantime, the sample was replaced with hydrocarbon air to measure oxygen
Response on Total Hydrocarbon Column to Deduce the interference of oxygen in the sample to total hydrocarbon determination.
5 Reagents and materials
Unless otherwise specified, analytical grade analytical reagents and distilled water in accordance with national standards were used.
5.1 In addition to hydrocarbon air. total hydrocarbon content (oxygen peak) ≤ 0.40 mg/m3 (in terms of methane); or methane column determination, deoxygenation
No other peak outside the peak.
5.2 Methane standard gas. 10.0 μmol/mol, equilibrium gas is nitrogen. Can also be based on actual work needs to qualified production
Commercially agreed to the appropriate concentration of standard gas.
5.3 Nitrogen. Purity ≥99.999%.
5.4 Hydrogen. Purity ≥99.99%.
5.5 Air. purification tube purification.
5.6 standard gas diluent gas. high purity nitrogen or nitrogen in addition to hydrocarbons, purity ≥ 99.999%, according to the sample determination (8.3) step test
Test, total hydrocarbon determination results should be lower than the detection limit of this standard method.
6 instruments and equipment
6.1 Sampling containers. all-glass syringe, the volume of not less than 100 ml, after cleaning and drying spare; airbag material in line with
HJ 732 of the relevant provisions of the volume of not less than 1 L, before use with hydrocarbon air (5.1) cleaning at least 3 times.
6.2 vacuum gas sampling box. the intake pipe, vacuum box, valves and suction pump and other components, the sample through the pipe material
The quality should not react with the tested components.
6.3 Gas Chromatograph. Hydrogen flame ionization detector.
6.4 Injector. Injection valve with 1 ml dosing tube or 1 ml airtight glass syringe.
6.5 column
6.5.1 packed column. methane column, stainless steel or hard glass, 2 m × 4 mm, filled with particle size 180 ~ 250 μm
(80-60 mesh) GDX-502 or GDX-104 support; total hydrocarbon column, stainless steel or hard glass, 2 m × 4 mm,
Filled with silanized glass beads with particle size of 180-250 μm (80-60 mesh).
6.5.2 Capillary column. methane column, 30 m × 0.53 mm × 25 μm porous layer Open tube Molecular sieve column or other equivalent capillary
Column; total hydrocarbon column, 30 m × 0.53 mm deactivated capillary air column.
6.6 General laboratory equipment and equipment.
7 samples
7.1 Sample Collection
Ambient air Dispensing and sampling in accordance with the relevant provisions of HJ 194 and HJ 664; Source of pollution Unorganized discharge Monitoring point Air
Place and sample according to HJ/T 55 or other relevant standards. Sampling vessels were sampled at least 3 times after air cleaning on site. To
Glass syringes were used to collect air samples on full scale and sealed with inert sealing heads. Samples were taken with an air bag and sampled with a vacuum gas
Tank (6.2) Introduce the air sample into the air bag to about 80% of the maximum volume and seal it immediately.
37.2 Transport blank
The sample container filled with hydrocarbon air (5.1) was taken to the sampling site and returned to the experiment together with the samples collected in the same batch
Room analysis.
7.3 Sample Storage
Glass syringes that collect samples should be handled with care to prevent damage and keep the needle tip down into the sample container
And shipping.
Samples at room temperature dark preservation, sampling completed as soon as possible after the analysis. Glass syringe preserved samples, place the time does not exceed 8 h;
The samples stored in the airbag should not be stored for more than 48 h. If methane is only measured, it should be completed in 7 days.
8 Analysis steps
8.1 Reference chromatographic conditions
Inlet temperature. 100 ° C.
Column temperature. 80 ° C.
Detector temperature..200 ° C.
Carrier gas. nitrogen (5.3), packed column flow 15 ~ 25 ml/min, capillary column flow 8 ~ 10 ml/min.
Burning gas. hydrogen (5.4), flow rate of about 30 ml/min.
Auxiliary gas. air (5.5), flow rate of about 300 ml/min.
Capillary gas makeup. nitrogen (5.3), flow 15 ~ 25 ml/min, splitless injection.
Injection volume. 1.0 ml.
8.2 Calibration
8.2.1 Preparation of calibration series
Take a 100 ml syringe (pre-placed in a thin piece of rigid Teflon) or 1 L air bag as a container, press 1.1
Volume ratio, standard gas diluent gas (5.6) methane standard gas (5.2) step by step diluted to prepare five concentration gradient
Calibration series, the calibration series concentrations were 0.625,1.25,2.50,5.00,10.0 mol/mol.
Note. The calibration series can be based on the actual situation to determine the appropriate concentration range, can also choose to use dynamic gas dilution instrument preparation, or to qualified production
Commercial custom.
8.2.2 Draw a calibration curve
From low concentration to high concentration in order to extract 1.0 ml calibration series (8.2.1), into the gas chromatograph (6.3) were measured
Total hydrocarbons, methane. Taking total hydrocarbon and methane concentration (μmol/mol) as the abscissa and its corresponding peak area as the ordinate,
Draw the total hydrocarbon, methane calibration curve.
Note. When the sample concentration and calibration gas concentration similar to the single-point calibration can be used, single-point calibration gas should be injected at least 2 times, the chromatographic response relative
Deviations should be ≤ 10%, calculated using the average.
48.2.3 standard chromatogram
Under the chromatographic analysis reference conditions (8.1) given in this standard, the standard chromatogram on the capillary column is shown in Figure 1. The packed column
The standard chromatogram shown in Figure 2.
(A) (b) (c)
a- Total hydrocarbon peak on total hydrocarbon column, b- Oxygen peak on total hydrocarbon column, c-Methane column on oxygen peak and methane peak
Fig.1 Standard chromatogram of total hydrocarbons, methane and oxygen on a capillary column
(A) (b) (c)
a- Total hydrocarbon peak on total hydrocarbon column, b- Oxygen peak on total hydrocarbon column, c-Methane column on oxygen peak and methane peak
Figure 2 Standard chromatograms of total hydrocarbons, methane and oxygen on packed columns
8.3 Sample Determination
8.3.1 Determination of total hydrocarbons and methane
The total hydrocarbon and methane peak area of the sample was determined following the same procedure and analytical conditions as for the calibration curve,
Peak area should be deducted oxygen peak area involved in the calculation.
NOTE Other peaks that appear after the total hydrocarbon peak should be taken into account in the total hydrocarbon peak area.
8.3.2 Determination of oxygen peak area
The same procedure and analytical conditions as for the calibration curve were used to determine the amount of hydrocarbon air (5.1) on the total hydrocarbon column
Oxygen peak area.
58.4 Blank test
Transport Blank Samples (7.2) Determine the same procedure and analytical conditions as for the calibration curve.
9 results calculated and expressed
9.1 Calculation Results
The total mass of hydrocarbons and methane in the sample is calculated according to formula (1).
22.4
1 (1)
Where. ρ-- total mass of hydrocarbons or methane in the sample (in terms of methane), mg/m3;
φ - the total hydrocarbon or methane concentration in the sample obtained from a calibration curve or a comparative single-point calibration point
Deduction of oxygen peak area), μmol/mol;
16 - the molar mass of methane, g/mol;
22.4 - Molar volume of gas at standard state (273.15 K, 101.325 kPa), L/mol.
Total mass concentration of non-methane hydrocarbons in the sample shall be calculated according to formula (2).
()
16NMHC THC M
2 (2)
Where. ρNMHC - sample mass concentration of non-methane total hydrocarbons (in terms of carbon), mg/m3;
ρTHC - mass concentration of total hydrocarbons in the sample (in methane), mg/m3;
ρM - mass concentration of methane in the sample (in terms of methane), mg/m3;
12 - the molar mass of carbon, g/mol;
16 - the molar mass of methane, g/mol.
Note 1. Total non-methane hydrocarbons may also need to be based on methane, and indicate.
Note 2. When methane is detected separately, the result can be converted into the expression of volume percentage.
9.2 results indicated
When the determination result is less than 1 mg/m3, keep to two decimal places; when the determination result is equal to or greater than 1 mg/m3,
Keep three significant figures.
10 precision and accuracy
10.1 Precision
Six laboratories had a total concentration of hydrocarbons (in terms of methane) of 1.47 mg/m3, 7.14 mg/m3 and 36.4 mg/m3
The samples were subjected to 6 replicate assays. The relative standard deviations in the laboratory were 1.0% -9.8%, 0.1% -6.0%, 0.6%
6.0%; relative standard deviations (RSDs) were 9.9%, 2.2% and 1.6% respectively; the repeatability limit was 0.27 mg/m3,
0.21 mg/m3, 1.8 mg/m3; reproducibility limit. 0.46 mg/m3, 0.49 mg/m3, 2.3 mg/m3. Each laboratory test
The relative standard deviation of actual ambient air samples with total hydrocarbon concentration (measured by methane) ranging from 0.85 mg/m3 to 4.71 mg/m3 was
0.7% ~ 6.0%.
66 laboratories for methane concentration (methane) of 1.47 mg/m3, 7.14 mg/m3 and 36.4 mg/m3 of unification
The samples were subjected to 6 replicate assays. The relative standard deviations in the laboratory were 2.6% -7.1%, 0.4% -2.5%, 1.0%
2.0%. The relative standard deviations of laboratory were 2.2%, 1.8% and 1.4% respectively. The reproducibility limit was 0.23 mg/m3,
0.37 mg/m3, 1.6 mg/m3; Reproducibility limit. 0.24 mg/m3, 0.50 mg/m3, 2.1 mg/m3. Each laboratory test
The relative standard deviation of actual ambient air samples with methane concentrations (measured by methane) ranging from 1.21 mg/m3 to 2.14 mg/m3 was
2.3% ~ 5.2%.
10.2 Accuracy
Six laboratories had a total concentration of hydrocarbons (in terms of methane) of 1.47 mg/m3, 7.14 mg/m3 and 36.4 mg/m3
The samples were subjected to 6 replicate measurements with relative errors of -9.7% -7.0%, -0.8% -5.1%, -1.7% -2.4%, respectively.
Final relative error. -0.8% ± 11.8%, 1.1% ± 4.6%, 0.1% ± 3.2%.
Six laboratories had a uniform concentration of methane (methane) of 1.47 mg/m3, 7.14 mg/m3 and 36.4 mg/m3
The samples were subjected to 6 replicate measurements with relative errors of -3.9% -4.8%, 0.5% -4.1%, -0.6% -0.3%, respectively.
Final relative error. 2.3% ± 6.4%, 1.8% ± 3.2%, -0.3% ± 0.6%.
11 Quality Assurance and Quality Control
11.1 Sampling containers should be cleaned before removal of hydrocarbon air (5.1) and then inspected. Every 20 or every batch (less
At 20) should be at least one injection of hydrocarbon air (5.1), placed at room temperature not less than the actual sample storage time, press
Sample analysis (8.3) Analysis of steps, total hydrocarbon determination results should be lower than the detection limit of this standard method.
Note. Reusable airbags, must be checked before sampling, total hydrocarbon determination results should be lower than the detection limit of this standard method.
11.2 Correlation coefficient of calibration curve should be greater than or equal to 0.995.
11.3 Transport Blank sample total hydrocarbon determination results should be lower than the detection limit of this standard method.
11.4 Each batch of samples should be analyzed at least 10% of the parallel samples in the laboratory, the relative deviation of the measurement results should not exceed 20%.
11.5 Before and after each sample analysis of the sample, the standard curve of the calibration curve should be measured within the standard gas, the results of the relative error should not be large
At 10%.
12 Precautions
12.1 Sampling containers should be thoroughly washed before use, air tightness test qualified, placed in a sealed sampling box to avoid contamination.
12.2 Samples returned to the laboratory should be balanced to ambient temperature after the determination.
12.3 Determination of complex samples, such as found in the analysis system residual, by increasing the column temperature and other ways to remove for analysis
Dehumidification of hydrocarbon air (5.1).
......
HJ 604-2011
Ambient air.Determination of total hydrocarbons.Gas chromatographic method
National Environmental Protection Standard of the People's Republic
Replace GB/T 15263-94
Ambient air - Determination of total hydrocarbons - Gas chromatography
Ambient air-Determination of total hydrocarbons
-Gas chromatographic method
Published on.2011-02-10
2011-06-01 Implementation
Ministry of Environmental Protection released
Content
Foreword..iv
1 Scope..1
2 Terms and definitions.1
3 method principle..1
4 Reagents and materials.1
5 instruments and equipment.1
6 samples. 2
7 Analysis steps..2
8 Results calculation and representation..3
9 precision and accuracy..4
10 Quality Assurance and Quality Control.4
11 Notes 4
Appendix A (informative appendix) Method for preparation of hydrocarbon removal air.5
Ministry of Environmental Protection
announcement
No. 9 of.2011
In order to implement the "Environmental Protection Law of the People's Republic of China", protect the environment, protect human health, and standardize environmental monitoring, the water is now approved.
The determination of total mercury is determined by the Cold Atomic Absorption Spectrophotometry and other nine standards for national environmental protection standards.
The standard name and number are as follows.
I. Determination of total mercury in water - Cold atomic absorption spectrophotometric method (HJ 597-2011);
2. Determination of water quality ladders by sodium sulfite spectrophotometry (HJ 598-2011);
3. Determination of water quality ladders N-chlorohexadecylpyridine-sodium sulfite spectrophotometry (HJ 599-2011);
4. Gas chromatographic method (HJ 600-2011) for the determination of water quality ladders, black ropes, and dien ladders;
5. Determination of water quality of formaldehyde - Acetylacetone spectrophotometry (HJ 601-2011);
6. Determination of water quality 石墨 Graphite furnace atomic absorption spectrophotometry (HJ 602-2011);
VII. Determination of water quality 火焰 Flame atomic absorption spectrophotometry (HJ 603-2011);
IX. Determination of Volatile Organic Compounds in Soils and Sediments Purge and Trap/Gas Chromatography-Mass Spectrometry (HJ 605-2011).
The above standards have been implemented since June 1,.2011 and published by the China Environmental Science Press. The standard content can be found on the website of the Ministry of Environmental Protection.
From the date of implementation of the above standards, the following seven national environmental protection standards approved and issued by the former National Environmental Protection Agency shall be abolished.
The name and number are as follows.
1. Determination of total mercury in water quality by cold atomic absorption spectrophotometry (GB 7468-87);
2. Determination of water quality ladders by sodium sulfite spectrophotometry (GB/T 13905-92);
3. Determination of water quality ladders by spectrophotometry (GB/T 13903-92);
4. Determination of water quality TNT, Hessian and Dien, gas chromatography (GB/T 13904-92);
V. Determination of water quality formaldehyde acetylacetone spectrophotometry (GB 13197-91);
6. Determination of water quality 原子 Atomic absorption spectrophotometry (GB/T 15506-1995);
VII. Determination of total hydrocarbons in ambient air Gas chromatography (GB/T 15263-94).
Special announcement.
February 10,.2011
Iv
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 established for the determination of the total hydrocarbons in the ambient air.
This standard specifies gas chromatography for the determination of total hydrocarbons in ambient air.
This standard is a revision of the "Gas Chromatography for Determination of Total Air in Ambient Air" (GB/T 15263-94).
This standard was first published in.1995. The original standard drafting unit was the Gansu Environmental Monitoring Center Station. This is the first revision. Revision
The main contents are as follows.
- modified the definition of total hydrocarbons;
- increased the principle of the method;
- Added a method for determining total hydrocarbons by capillary empty columns;
-- Added standard calculation method for standard curve;
-- Added quality assurance and quality control provisions.
From the date of implementation of this standard, the national environmental protection standard approved by the former National Environmental Protection Agency on October 26,.1994
Determination of total hydrocarbons in the air by gas chromatography (GB/T 15263-94) is abolished.
Appendix A of this standard is an informative annex.
This standard was formulated by the Science and Technology Standards Department of the Ministry of Environmental Protection.
This standard is mainly drafted by. Changzhou Environmental Monitoring Center Station.
This standard is verified by. Jiangsu Environmental Monitoring Center, Suzhou Environmental Monitoring Center Station, Jiangsu Province, Nantong City Environmental Monitoring
Xinzhe, Environmental Monitoring Center Station of Zhenjiang City, Jiangsu Province, Environmental Monitoring Center Station of Suzhou Industrial Park, Jiangsu Province and Wujin District, Changzhou City, Jiangsu Province
Monitoring station.
This standard was approved by the Ministry of Environmental Protection on February 10,.2011.
This standard has been implemented since June 1,.2011.
This standard is explained by the Ministry of Environmental Protection.
Ambient air - Determination of total hydrocarbons - Gas chromatography
1 Scope of application
This standard specifies gas chromatography for the determination of total hydrocarbons in ambient air.
This standard applies to the determination of total hydrocarbons in ambient air.
When the injection volume is 1.0 ml, the detection limit of this method is 0.04 mg/m3, and the lower limit of determination is 0.16 mg/m3.
2 Terms and definitions
The following definitions apply to this standard.
Total hydrocarbons
Refers to the total amount of gaseous hydrocarbons and their derivatives measured by a hydrogen flame detector under the conditions specified in this standard, in terms of methane.
3 Principle of the method
The sample is directly injected into the gas chromatograph, and the total amount of total hydrocarbons and oxygen (in methane) in the sample is determined by a hydrogen flame ionization detector.
At the same time, the content of oxygen (calculated as methane) can be measured by using the dehydrogenated air instead of the sample, and the total hydrocarbon is deducted from the total amount of the two.
The content.
4 reagents and materials
Analytical purification reagents conforming to national standards were used for analysis, unless otherwise stated, and the experimental water was distilled water.
4.1 Phosphoric acid. ρ = 1.75 g/ml.
4.2 Phosphoric acid solution. c (H3PO4) = 3.3 mol/L.
Measure 38 ml of phosphoric acid (4.1) in a 100 ml volumetric flask, dilute to the mark with water, and mix.
4.3 Hydrocarbon removal air. Total hydrocarbon content (oxygen peak) ≤ 0.4 mg/m3 (calculated as methane), purchased directly or prepared by yourself, see Appendix A.
4.4 Methane standard gas. 10.0 μmol/mol, using nitrogen as the base gas.
4.5 Combustion gas. hydrogen, purity (volume fraction) ≥ 99.99%.
4.6 Carrier gas. nitrogen, purity (volume fraction) ≥ 99.99%.
4.7 Gas. Air, cleaned with a clean tube.
4.8 Dilution gas. high purity nitrogen, purity (volume fraction) ≥ 99.999%.
5 Instruments and equipment
5.1 Gas Chromatograph. Hydrogen flame ionization detector.
5.2 Injector. 1 ml airtight glass syringe or six-way valve with 1 ml dosing tube.
5.3 Column
5.3.1 Packed column. made of stainless steel or hard glass, 1~2 m long, 5 mm inner diameter, filled with silanized glass beads (60-80)
(mesh), or other equivalent packed column. Preparation method of packed column. one end of the stainless steel column is plugged with glass wool and connected to a vacuum pump; the other end of the column is connected
Pass the hose to the funnel and slowly load the carrier into the column through the funnel. While loading the body, turn on the vacuum pump and gently tap the color.
The column allows the support to be packed tightly and evenly in the column, and is filled with glass wool after filling. In order to prevent the glass wool and the support from being drawn into the vacuum pump,
A capillary tube and buffer bottle are connected between the vacuum pump and the column.
5.3.2 Capillary empty column. 15 m × 0.53 mm, or other equivalent capillary empty column.
5.3.3 Column aging. Connect one end of the column to the instrument inlet and the other end to the detector, with a low flow rate (filled column approximately
10 ml/min, capillary empty column about 4 ml/min), and the column temperature was raised to.200 ° C for about 24 h, then the column was connected to the chromatogram.
System, until the baseline is straight.
5.4 Syringes. 1, 5, 20, 50, 100 ml, all glass.
5.5 Common instruments and equipment used in general laboratories.
6 samples
6.1 Washing of sampling containers
The syringe is washed with a phosphoric acid solution (4.2) before use, then washed with water, dried and ready for use.
6.2 Sample Collection and Storage
At the height of the person's breathing zone, a sample of ambient air is drawn using a 100 ml syringe. Repeatedly pumping the sample 3 times before sampling, and then picking
Set 100 ml sample, seal with rubber cap, keep away from light, and analyze it in days.
7 Analysis steps
7.1 Reference chromatographic conditions
Inlet temperature. 70 ~ 100 ° C
Column temperature. 70 ° C
Detector temperature. 150 ° C
Carrier gas. nitrogen (4.6) flow through the packed column 40 ~ 50 ml/min, nitrogen (4.6) flow through the capillary empty column 8 ~
10 ml/min.
Combustion gas. hydrogen (4.5) flow rate of about 30 ml/min.
Helping gas. Air (4.7) flow rate is about 300 ml/min.
Blowing gas. nitrogen (4.6), nitrogen (4.6) flow through the capillary empty column was 25 ml/min.
Injection volume. 1.0 ml.
7.2 Calibration
7.2.1 Preparation of the standard series
Using a 100 ml syringe (previously placed in a piece of hard Teflon), in a volume ratio of 1.1, with a high purity nitrogen (4.8)
Alkaline standard gas (4.4) is diluted step by step to prepare five concentration gradient standard gases. The standard series has a mole fraction of 0.625 and 1.25, respectively.
2.50, 5.00, 10.0 μmol/mol.
7.2.2 Drawing a standard curve
The 1.0 ml standard series (7.2.1) is sequentially extracted from the low concentration to the high concentration, and is injected into the gas chromatograph to determine the peak area as the ordinate.
A standard curve is drawn with the total hydrocarbon content (μmol/mol) as the abscissa.
7.2.3 Standard chromatogram
Figure 1 and Figure 2 are standard chromatograms of total hydrocarbons and hydrocarbon-depleted air (oxygen peaks) under the chromatographic conditions specified in this standard.
1.
1.
Figure 1 Total hydrocarbon chromatogram (0.184 min) Figure 2 Hydrocarbon air (oxygen peak) chromatogram (0.185 min)
7.3 Determination
Take 1.0 ml of the sample to be tested (when the sample concentration is higher than the highest point of the standard curve, apply the demineralized air (4.3) for proper dilution),
The peak conditions were determined by the same chromatographic conditions as the standard curve.
Note. When the sample concentration is close to the standard gas concentration, a single point quantitative determination can be performed.
7.4 Determination of oxygen peak
Take 1.0 ml of the hydrocarbon-depleted air (4.3) and measure the peak area according to the same procedure as in the measurement (7.3).
8 Calculation and representation of results
8.1 Calculation of results
8.1.1 Standard curve method
The mass concentration ρ of the total hydrocarbon in the sample is calculated according to the formula (1).
16( )
22.4
Kρ φ φ= − × (1)
Where. ρ--the mass concentration of total hydrocarbons in the sample (in methane), mg/m3;
1φ - the mole fraction of total hydrocarbons (in methane) in the sample as found on the standard curve, μmol/mol;
0φ - the mole fraction of oxygen (in methane) in the sample as found on the standard curve, μmol/mol;
K--the dilution factor of the sample;
16--molar mass of methane, g/mol;
22.4-- Standard state (273.15 K, 101.325 kPa), the molar volume of gas, L/mol.
8.1.2 Single point method
The mass concentration ρ of the total hydrocarbon in the sample is calculated according to the formula (2).
ρ φ= × 16
22.4
× (2)
Where. ρ--the mass concentration of total hydrocarbons in the sample (in methane), mg/m3;
Φ--molar fraction of methane in methane standard gas, μmol/mol;
S--the peak area of the sample after subtracting the oxygen peak;
1S - Peak area of methane standard gas.
8.2 Results representation
When the measurement result is less than 1 mg/m3, it is retained to two decimal places; when the result is greater than 1 mg/m3, three significant figures are retained.
9 Precision and accuracy
9.1 precision
Packed column. 5 laboratories tested the 1.42 mg/m3 and 3.55 mg/m3 methane standard samples, respectively.
The deviations were 3.3% and 2.2%, respectively, and the relative standard deviations of reproducibility were 3.6% and 2.3%, respectively.
Capillary empty column. Six laboratories measured the uniform samples containing methane mass concentrations of 1.47, 7.14 and 36.4 mg/m3, respectively.
The relative standard deviations in the laboratory were 1.0%-8.3%, 0.0%~2.9%, and 0.6%~3.7%, respectively. The relative standard deviations between laboratories were
4.8%, 2.2%, 1.6%; repeatability limits were 0.25, 0.31, 2.1 mg/m3; reproducibility limits were 0.30, 0.53, 2.48 mg/m3.
9.2 Accuracy
Packed columns. 5 laboratories tested the 1.42 mg/m3 and 3.55 mg/m3 methane standard samples, respectively. The relative errors were
3.5% and −3.8%, the recovery rate of ambient air samples was 81.7%~111%.
Capillary empty column. Six laboratories measured the uniform samples with methane concentrations of 1.47, 7.14 and 36.4 mg/m3, respectively.
The error is −5.4%～6.8%, −0.8%～5.0%, −1.1%～2.5%, and the relative error final value −0.1%±4.8%, 1.0%±2.4%,
0.0% ± 1.6%. Six laboratories carried out spiked recovery tests on ambient air samples with a total hydrocarbon concentration ranging from 1.36 to 4.71 mg/m3.
The spiked recovery ranged from 84.6% to 118%.
10 Quality Assurance and Quality Control
10.1 The correlation coefficient of the standard curve is ≥0.995, otherwise the standard curve is redrawn.
10.2 For each sample analyzed, the intermediate curve checkpoint of the standard curve shall be determined, and the relative deviation between the measured value and the corresponding value of the calibration curve shall be
≤10%, otherwise the standard curve should be redrawn.
10.3 At least 10% of parallel samples should be collected for each batch of samples, and the relative deviation of the measured results is ≤10%.
11 Precautions
11.1 Sampling syringes should be thoroughly washed before use. Strict air tightness checks are applied to the syringe. The sampling syringe should be placed in a closed sampling box
To avoid pollution.
11.2 After the sample is collected, it should be stored away from light and the sampling syringe should be placed vertically.
11.3 The sample should be returned to room temperature before measurement.
Appendix A
(informative appendix)
Method for preparing hydrocarbon removal air
A.1 Preparation of hydrocarbon removal air by a hydrocarbon removal unit
A.1.1 Reagents and materials
A.1.1.1 Palladium catalyst. palladium chloride (PdCl2), AR.
A.1.1.2 Silica gel. AR.
A.1.1.3 Alkali asbestos. AR.
A.1.1.4 Activated carbon.
A.1.1.5 5A molecular sieve. AR.
A.1.2 Palladium-6201 catalytic hydrocarbon removal unit, see Figure A.1.
6 air
1. Oil-free compressor; 2. Steady flow valve; 3. Silica gel and 5A molecular sieve; 4. Activated carbon; 5.1 m preheating tube;
6. High temperature tube furnace (450 ~ 500 ° C); 7. Silica gel and 5A molecular sieve; 8. Caustic soda
Figure A.1 Diagram of a hydrocarbon removal air purification unit (palladium catalyst)
A.1.3 Operation steps
A.1.3.1 Preparation of hydrocarbon removal catalytic tubes
The U-shaped tube is a stainless steel tube with an inner diameter of 4 mm, which contains 10 g of catalyst palladium-6201, the bed height is 7-8 cm, and the length of the U-shaped tube is 1 m long.
Stainless steel preheating tube with an inner diameter of 4 mm.
Note. Preparation of palladium-6201 catalyst. take a certain amount of palladium chloride (PdCl2), dissolve it with deionized water under acidic conditions, and the amount of solution should be immersed.
10 g 6201 carrier (60-80 mesh) is suitable. Leave it for 2 h, evaporate it with gentle agitation, then place it in a U-tube and place it in a heating oven.
Dry at 100 ° C for 30 min, then warm to 500 ° C for 4 h, then reduce the temperature to 400 ° C, replace with nitrogen for 10 min, then
Hydrogen reduction was carried out for 9 h. Replace with nitrogen for 10 min. That is, a dark brown palladium-6201 catalyst was obtained.
A.1.3.2 Inspection of hydrocarbon removal air
The hydrocarbon removal air purification device passes through the indoor air or air cylinder, the furnace temperature rises to 450-500 ° C, and the temperature is constant for 2 h, then the hydrocarbon purification is removed.
Air to column (5.3), total hydrocarbon content (oxygen peak) ≤ 0.4 mg/m3 (in methane), or remove hydrocarbon purification air to GDX-502
Column chromatography determined no peak, ie it was considered to be completely hydrocarbon.
A.2 Preparation of hydrocarbon-depleted air with high purity nitrogen and high purity oxygen
A.2.1 Reagents and materials
A.2.1.1 High purity nitrogen. purity ≥ 99.999%.
A.2.1.2 High purity oxygen. purity ≥ 99.999%.
A.2.1.3 Glass syringe. 100 ml, several.
A.2.2 Operation steps
A.2.2.1 Preparation of hydrocarbon removal air
High-purity nitrogen (A.2.1.1) and high-purity oxygen (A.2.1.2) were extracted in a 100 ml glass syringe at a volume ratio of 4.1 (pre-inserted in one
Mix in a piece of hard polytetrafluoroethylene).
A.2.2.2 Inspection of hydrocarbon removal air
Remove hydrocarbon air (A.2.2.1) to the column (5.3), total hydrocarbon content (oxygen peak) ≤ 0.4 mg/m3 (in methane), or take
The hydrocarbon removal air (A.2.2.1) to GDX-502 column chromatography showed no peak, which is considered to be complete in addition to hydrocarbons.
......
|