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This standard was developed with a view to implementing the Environmental Protection Law of the People's Republic of China and the Law on Prevention of Air Pollution of the People's Republic of China, protecting environment, guaranteeing human health, and standardizing determination methods of total hydrocarbons, methane and nonmethane hydrocarbons in the ambient air.
This standard specifies direct injection/gas chromatography for determination of total hydrocarbons, methane and nonmethane hydrocarbons in the ambient air.
This standard is a revision to HJ 604-2011 Ambient Air-Determination of Total Hydrocarbons-Gas Chromatographic Method.
This standard was issued in 1994 for the first time; the former standard GB/T 15263-1994 was developed by Gansu Environmental Monitoring Center; it was revised in 2011 for the first time. This edition is the second revision. The following changes have been made:
——the determination indexes are expanded to cover methane and nonmethane hydrocarbons, and the standard name is modified accordingly;
——the application scope incorporates determination of total hydrocarbons, methane and nonmethane hydrocarbons in the air at fugitive emission monitoring points;
——the definition of total hydrocarbons is modified, and the definition of nonmethane hydrocarbons is added;
——air bag is used as the sampling container, and sample collection, preservation mode and preservation period are specified;
——quality assurance and quality control requirements are added;
——the annexes are deleted.
HJ 604-2011 Ambient Air-Determination of Total Hydrocarbons-Gas Chromatographic Method is cancelled from the implementation date of this standard.
This standard was established under the organization of the Department of Environment Monitoring and Department of Science, Technology and Standards under the Ministry of Environmental Protection.
This standard was approved by the Ministry of Environmental Protection on December 14, 2017.
This standard shall be implemented from March 1, 2018.
The Ministry of Environmental Protection is in charge of the explanation of the standard.
Ambient Air—
Determination of Total Hydrocarbons, Methane and Nonmethane Hydrocarbons—
Direct Injection/Gas Chromatography
1 Application Scope
This standard specifies direct injection/gas chromatography for determination of total hydrocarbons, methane and nonmethane hydrocarbons in the ambient air.
This standard is applicable to determination of total hydrocarbons, methane and nonmethane hydrocarbons in the ambient air and determination of total hydrocarbons, methane and nonmethane hydrocarbons in the air at fugitive emission monitoring points of pollution sources.
In the case of injection volume of 1.0 ml, for total hydrocarbons and methane, the detectable limits are both 0.06mg/m3 (by methane) and the lower limits of determination are both 0.24 mg/m3 (by methane); for nonmethane hydrocarbons, the detectable limit is 0.07 mg/m3 (by carbon) and the lower limit of determination is 0.28 mg/m3 (by carbon).
2 Normative References
For the purpose of this standard, the following documents or their provisions are quoted. For undated references, the valid versions apply to this standard.
HJ 194 Manual Methods for Ambient Air Quality Monitoring
HJ 664 Technical Regulation for Selection of Ambient Air Quality Monitoring Stations (On Trial)
HJ 732 Emission from Stationary Sources—Sampling of Volatile Organic Compounds—Bags Method
HJ/T 55 Technical Guidelines for Fugitive Emission Monitoring of Air Pollutants
3 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
total hydrocarbons (THC)
a generic term for responsive gaseous organic compounds on hydrogen flame ionization detector of gas chromatograph under the determination conditions specified in this standard.
3.2
nonmethane hydrocarbons (NMHC)
a generic term for gaseous organic compounds other than methane in total hydrocarbons under the determination conditions specified in this standard (unless otherwise specified, the result is calculated by carbon).
4 Principle
Gas sample is directly injected into a gas chromatograph with hydrogen flame ionization detector, and contents of total hydrocarbons and methane are measured on total hydrocarbon column and methane column respectively. The difference between the content of total hydrocarbons and the content of methane is the content of nonmethane hydrocarbons. Meanwhile, hydrocarbon-free air is used to replace the sample for determination of response value of oxygen on the total hydrocarbon column, to deduct interference of oxygen in the sample to determination of total hydrocarbons.
5 Reagents and Materials
Unless otherwise specified, analytically pure chemical reagents and distilled water as specified in the national standards shall be used for analysis.
5.1 Hydrocarbon-free air: total hydrocarbon content (including oxygen peak) ≤0.40mg/m3 (by methane); or determination on methane column, no peaks other than oxygen peak.
5.2 Standard methane gas: 10.0 μmol/mol; nitrogen is used as equilibrium gas. It is also allowed to make standard gas of appropriate concentration at qualified manufacturer's according to the actual job demand.
5.3 Nitrogen: with the purity ≥99.999%.
5.4 Hydrogen: with the purity ≥99.99%.
5.5 Air: purified via a purification pipe.
5.6 Diluted gas from standard gas: high-purity nitrogen or hydrocarbon-free nitrogen, with the purity ≥99.999%, tested according to the procedures of sample determination (8.3), and determination result of total hydrocarbons shall be lower than the detectable limit of the method in this standard.
6 Apparatus
6.1 Sampling container: all-glass syringe, not less than 100mL in volume, cleaned and dried for use; air bag syringe, conforming to the relevant requirements of HJ 732, not less than 1L, cleaned at least 3 times with hydrocarbon-free air (5.1) prior to use.
6.2 Vacuum gas sampling kit: consisting of intake tube, vacuum chamber, valve, and suction pump, etc. Material of tube through which samples flow shall not react with the tested component.
6.3 Gas chromatograph: with hydrogen flame ionization detector.
6.4 Sample injector: injection valve with 1 ml quantitative tube or 1 ml airtight glass syringe.
6.5 Chromatographic column
6.5.1 Packed column: methane column, stainless steel or hard glass material, 2 m × 4 mm, filled with GDX-502 or GDX-104 supporter of 180~250 μm (80~60 meshes) in particle size; total hydrocarbon column, stainless steel or hard glass, 2 m×4 mm, filled with silanized glass microballoon of 180~250 μm (80~60 meshes) in particle size.
6.5.2 Capillary column: methane column, 30 m × 0.53 mm × 25 μm, porous-layer molecular sieve column with open tube or other equivalent capillary columns; total hydrocarbon column, 30 m × 0.53 mm, deactivated void capillary column.
6.6 Common laboratory instruments and equipment.
7 Samples
7.1 Sample collection
Ambient air locating and sampling shall conform to the relevant requirements of HJ 194 and HJ 664; air locating and sampling at fugitive emission monitoring points of pollution sources shall conform to the relevant requirements of HJ/T 55 or other relevant standards. The sampling container is cleaned with air in the field at least three times prior to sampling. The glass syringe collects air sample to the full scale, which is then sealed with an inert sealing head; in the case of air bag is used to collect sample, the vacuum gas sampling kit (6.2) is used to lead air sample into the air bag to about 80% of the maximum volume, which is then sealed immediately.
Foreword i
1 Application Scope
2 Normative References
3 Terms and Definitions
4 Principle
5 Reagents and Materials
6 Apparatus
7 Samples
8 Analytical Procedure
9 Calculation and Expression of Results
10 Precision and Accuracy
11 Quality Assurance and Control
12 Considerations
