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HJ 1067-2019: Water quality--Determination of benzene and its analogies--Headspace / gas chromatography
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Water quality--Determination of benzene and its analogies--Headspace / gas chromatography
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HJ 1067-2019
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Basic data | Standard ID | HJ 1067-2019 (HJ1067-2019) | | Description (Translated English) | Water quality--Determination of benzene and its analogies--Headspace / gas chromatography | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z16 | | Classification of International Standard | 13.060.01 | | Word Count Estimation | 15,192 | | Date of Issue | 2019 | | Date of Implementation | 2020-03-24 | | Issuing agency(ies) | Ministry of Ecology and Environment | HJ 1067-2019: Water quality--Determination of benzene and its analogies--Headspace / gas chromatography
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Water quality--Determination of benzene and its analogies--Headspace/gas chromatography
National Environmental Protection Standard of the People's Republic of China
Determination of benzene in water
Headspace/gas chromatography
Water quality-Determination of benzene and its analogies
-Headspace/gas chromatography
2019-12-24 released
2020-03-24 implementation
Ministry of Ecology and Environment
i table of contents
Foreword ... ii
1 Scope ... 1
2 Normative references ... 1
3 Methodology ... 1
4 Reagents and materials ... 1
5 Instruments and equipment ... 2
6 Sample ... 2
7 Analysis steps ... 3
8 Results calculation and representation ... 4
9 Precision and accuracy ... 5
10 Quality Assurance and Quality Control ... 5
11 Waste disposal ... 6
12 Notes ... 6
Appendix A (Normative) Limits of Detection and Determination of Target Compounds ... 7
Appendix B (Informative) Supplementary Qualitative Reference Chromatograms ... 8
Appendix C (Informative) Method Precision and Accuracy ... 9
Foreword
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 Water Pollution Control", protect the ecology
The environment, to protect human health, standardize the determination method of benzene series in water, and formulate this standard.
This standard specifies headspace/gas chromatography for the determination of benzenes in surface water, groundwater, domestic sewage and industrial wastewater.
Compared with "Gas Chromatography for the Determination of Benzene in Water" (GB/T 11890-1989), the main differences between this standard are as follows.
under.
-The name was changed to "Determination of benzene in water by headspace/gas chromatography";
-Increased groundwater and domestic sewage in the scope of application;
-Deleted liquid-liquid extraction related content;
-Added normative references;
-Added description of method principle;
-Change the packed column for analysis to a capillary column and use a fully automatic headspace sampler instead of a manual headspace sampler;
-Change the single-point calibration to the working curve calibration;
-Added chapters on quality assurance and quality control;
-Added chapter on waste disposal and precautions.
Since the implementation of this standard, the former National Environmental Protection Agency approved "Water Quality Benzene Series" on December 25, 1989.
Gas Chromatography (GB/T 11890-1989) in the corresponding environmental quality standards and pollutant emissions (control)
Implementation stopped during the implementation of the standard.
Appendix A of this standard is a normative appendix, and Appendix B and Appendix C are informative appendixes.
This standard is formulated by the Department of Eco-Environmental Monitoring, Laws and Standards Department of the Ministry of Ecology and Environment.
This standard was drafted. China Shipbuilding Industry Corporation 718 Research Institute.
This standard is verified by. Hebei Province Environmental Monitoring Center Station, Shijiazhuang City Environmental Monitoring Station, Anyang City Environmental Monitoring Station,
Baoding Environmental Monitoring Station, China Shipbuilding Chemicals Testing Center and Beijing Huaxue North Testing Technology Co., Ltd.
This standard was approved by the Ministry of Ecology and Environment on December 24,.2019.
This standard will be implemented from March 24, 2020.
This standard is explained by the Ministry of Ecology and Environment.
1 Determination of benzene compounds in water quality Headspace/gas chromatography
Warning. The solvents and standard samples used in the experiment are toxic and harmful compounds, their solution preparation and sample preparation process
It should be carried out in a fume hood, and protective equipment should be worn during operation to avoid contact with skin and clothing.
1 Scope
This standard specifies headspace/gas chromatography for the determination of benzenes in water.
This standard applies to benzene, toluene, ethylbenzene, p-xylene, methane in surface water, groundwater, domestic sewage and industrial wastewater.
Determination of xylene, o-xylene, cumene and styrene.
When the sampling volume is 10.0 ml, the detection limit of this standard for the determination of benzene in water is 2 µg/L to 3 µg/L
The lower limit is set to 8 µg/L to 12 µg/L. See Appendix A for details.
2 Normative references
This standard refers to the following documents or clauses therein. For undated references, the valid version applies to this
standard.
HJ 494 Water Quality Sampling Technical Guide
HJ 91.1 Technical Specifications for Sewage Monitoring
HJ/T 91 Technical specifications for surface water and sewage monitoring
HJ/T 164 Technical Specifications for Groundwater Environmental Monitoring
3 Method principle
Place the sample in a closed headspace bottle. Under a certain temperature and pressure, the volatile components in the sample in the headspace bottle are transferred to the liquid.
The upper space volatilizes and generates vapor pressure. The thermodynamic equilibrium is reached in the two phases of gas and liquid. Within a certain concentration range, the benzene series
The concentration in the gas phase is proportional to the concentration in the water phase. Quantitative extraction of gas phase was separated by gas chromatography and hydrogen flame ionization
Detector detection. Qualitative according to retention time, quantified by external standard method of working curve.
4 Reagents and materials
Unless otherwise specified, analytical purification reagents that meet national standards are used. Experimental water is double distilled water
Or water prepared by pure water equipment, it needs to go through a blank test before use to confirm that it does not contain the target compound and
No interference chromatographic peaks appeared during the retention time interval.
4.1 Methanol (CH3OH). chromatographically pure.
4.2 Hydrochloric acid. ρ (HCl) = 1.19 g/ml, excellent purity.
4.3 Sodium chloride (NaCl). excellent grade pure.
Before use, burn at 500 ° C to 550 ° C for 2 hours, cool to room temperature, and store in a desiccator for later use.
4.4 Ascorbic acid (C6H8O6).
24.5 Hydrochloric acid solution. 1 1.
4.6 Standard stock solution. ρ≈1.00 mg/ml, the solvent is methanol.
Commercially available certified standard solutions, sealed and refrigerated at 4 ° C or lower in the dark, or stored in accordance with product instructions. Should be restored before use
Mix to room temperature.
4.7 Standard use solution. ρ≈100 µg/ml.
Accurately transfer 1.00 ml of standard stock solution (4.6) and make up to 10 ml with water. Provisional use.
4.8 Carrier gas. High-purity nitrogen with a purity of ≥99.999%.
4.9 Combustion gas. high-purity hydrogen, purity ≥99.999%.
4.10 Gas-assisting gas. air, dehydrated by silica gel, and activated carbon to remove organic matter.
5 Instruments and equipment
5.1 Sampling bottle. 40 ml brown screw-top glass bottle with silicone rubber-teflon liner screw cap.
5.2 Gas chromatograph. with split/splitless inlet and hydrogen flame ionization detector (FID).
5.3 Column I. Specifications are 30 m (column length) × 0.32 mm (inner diameter) × 0.5 μm (film thickness), 100% polyethylene glycol
Stationary capillary columns, or other equivalent capillary columns.
5.4 Column II. Specifications are 30 m (column length) x 0.25 mm (inner diameter) x 1.4 μm (film thickness), 6% nitrile-propylphenyl 94%
Dimethyl polysiloxane stationary phase capillary columns, or other equivalent capillary columns.
5.5 Automatic headspace sampler. The temperature control accuracy is ± 1 ° C.
5.6 Headspace bottle. headspace bottle (22 ml), polytetrafluoroethylene (PTFE)/silicone gasket, cap (screw cap or primary
Gland used), or a glass headspace vial fitted with an automatic headspace sampler (5.5).
5.7 Pipette. 1 ml to 10 ml.
5.8 Glass micro-syringe. 10 μl ～ 100 μl.
5.9 General laboratory instruments and equipment.
6 samples
6.1 Sample collection
Collect samples in accordance with the relevant regulations of HJ/T 91, HJ 91.1, HJ/T 164 and HJ 494.
Before sampling, measure the pH of the sample. According to the pH measurement result, add an appropriate amount of hydrochloric acid to the sampling bottle (5.1).
(4.5) and add 25 mg of ascorbic acid (4.4) to make the sample pH ≤ 2 after sampling. If the sample is added with hydrochloric acid solution
If air bubbles are generated, re-sampling is required. The re-collected samples are stored without adding hydrochloric acid solution. The sample label must indicate that it is not acidified.
When collecting samples, allow the sample to overflow in the vial without leaving space on the liquid. Try to avoid or reduce the
Exposed in the air. All samples were taken in duplicate.
Note. The sample bottle should be washed and dried with methanol (4.1) before sampling. It is not necessary to rinse the sample with the sample.
6.2 Collection of blank samples during the whole procedure
Bring the experimental water to the sampling site and follow the same procedure (6.1) as the sample collection to collect a blank sample of the entire procedure.
36.3 Sample preservation
After the samples are collected, they should be transported and stored refrigerated below 4 ° C, and the analysis should be completed within 14 days. Sample storage area should be non-volatile
Organic matter interferes, the sample should be returned to room temperature before measurement.
Note. Non-acidified samples should be analyzed within 24 h.
6.4 Preparation of test specimens
Add 3 g of sodium chloride (4.3) to the headspace bottle (5.6), add 10.0 ml of sample (6.3), and immediately seal
Seal, shake well and test.
6.5 Preparation of laboratory blank samples
Use experimental water to replace the sample, and follow the same steps as in the sample preparation (6.4) to prepare a laboratory blank sample.
Equipment.
7 Analysis steps
7.1 Instrument reference conditions
7.1.1 Headspace Sampler Reference Conditions
Heating equilibrium temperature. 60 ℃; Heating equilibration time. 30 min; Sample valve temperature. 100 ℃; Transmission line temperature. 100 ℃;
Injection volume. 1.0 ml (loop).
7.1.2 Gas chromatograph reference conditions
Inlet temperature..200 ° C; Detector temperature. 250 ° C; Column column heating program. 40 ° C (hold for 5min), at 5 ° C
/ min The temperature rises to 80 ° C (hold for 5 min); carrier gas flow rate. 2.0 ml/min; combustion gas flow rate. 30 ml/min; combustion support
Air flow rate. 300 ml/min; makeup air flow rate. 25 ml/min; split ratio is 10. 1.
7.2 Establishment of working curve
Add 3 g of sodium chloride (4.3) to the 7 headspace bottles (5.6), and then add 10.0 ml, 10.0 ml,
10.0 ml, 9.8 ml, 9.6 ml, 9.2 ml, and 8.8 ml water, then add 5.00 µl,
20.0 µl, 50.0 µl, 0.20 ml, 0.40 ml, 0.80 ml, and 1.2 ml standard use solutions (4.7), formulated into the target compound
The mass concentrations are 0.050 mg/L, 0.200 mg/L, 0.500 mg/L, 2.00 mg/L, 4.00 mg/L, 8.00 mg/L,
12.0 mg/L standard series (this is the reference concentration, at least 5 non-zero concentration points can be selected to cover the sample concentration range),
Immediately seal the headspace bottle, shake gently, and inject and analyze from low concentration to high concentration in accordance with the instrument reference conditions (7.1)
Record the retention time and response values of the standard series of targets. Take the target compound concentration as the abscissa and its corresponding response value
For the ordinate, create a working curve.
7.3 Sample determination
The measurement of the sample (6.4) is performed under the same conditions as the establishment of the working curve (7.2).
Note. If the sample concentration exceeds the highest concentration point of the working curve, you need to re-sample from the unopened sample bottle, and then re-dilute the sample after dilution.
Preparation of 4 (6.4).
7.4 Laboratory blank test
Follow the same procedure as for the sample measurement (7.3) to measure the laboratory blank sample (6.5).
8 Results calculation and representation
8.1 Qualitative analysis
Qualitative based on the retention time of the target in the sample and the target in the standard series. Before sample analysis, when establishing retention
The window t ± 3S. t is the average retention time of the target compound at each concentration level during calibration, and S is the concentration level at each initial calibration level
Standard deviation of target compound retention time. During sample analysis, the target should peak within the retention time window.
When it is detected on column I (5.3) but cannot be confirmed, column II (5.4) can be used for auxiliary characterization. color
The reference conditions for the determination of column II are the same as the reference conditions of the instrument (7.1). See Appendix B for the standard chromatograms of benzene series.
Under the measurement conditions specified in this standard, the standard reference chromatogram of benzene series is shown in Figure 1.
1-methanol; 2-benzene; 3-toluene; 4-ethylbenzene; 5-p-xylene; 6-m-xylene; 7-cumene; 8-o-xylene; 9-styrene.
Figure 1 Standard chromatogram of benzene series on column I (6000 µg/L)
8.2 Calculation of results
The mass concentration (µg/L) of the target compound in the sample is calculated according to formula (1).
% 00% 00% 00% 00% 00% 00% 00 (1)
In the formula. I-mass concentration of the target compound in the sample, µg/L;
i-mass concentration of target compound obtained from the working curve, µg/L;
D--The dilution factor of the sample.
58.3 result representation
The number of digits after the decimal point in the measurement result is the same as the detection limit of the method. A maximum of 3 significant digits are retained.
9 Precision and accuracy
9.1 Precision
Six laboratories performed six replicates of benzene series uniformly mixed standard samples at concentration levels of 20 µg/L and 100 µg/L
Re-assay. the relative standard deviations in the laboratory are 1.6% to 15% and 2.1% to 9.5%; the relative standard deviations between laboratories
8.2% ～ 12% and 2.7% ～ 5.6% respectively; repeatability limits r are 4 μg/L ～ 4 μg/L and 12 μg/L ～ 19 μg/L;
Reproducibility limits R are 6 μg/L to 8 μg/L and 14 μg/L to 23 μg/L, respectively.
1 laboratory performed standard mixtures of benzene series at 50 µg/L,.2000 µg/L and 10,000 µg/L
Six repeated determinations were performed. the relative standard deviations in the laboratory were. 5.6% to 9.2%, 2.9% to 7.8%, and 1.9% to 2.6%.
9.2 Accuracy
Six laboratories performed six repeated spiking analyses on surface water samples with a spiked concentration of 100 μg/L. average spiking
The standard recovery range is 85.9% ～ 122%; the final recovery range of standard addition is 102% ± 13.0% ～ 106% ± 11.0%.
One laboratory performed 6 repeated spiking analyses on groundwater samples spiked at 500 μg/L. average spiking
The standard recovery range is 78.4% ～ 91.6%; the final recovery range of standard addition is 84.6% ± 7.8% ～ 88.4% ± 6.0%.
One laboratory performed 6 repeated spiking analyses on domestic sewage samples with a spiked concentration of 1000 μg/L.
The average spike recovery rate range is 76.1% ~ 92.6%; the final spike recovery rate range is 80.1% ± 7.9% ~ 87.6% ± 5.7%.
1 laboratory has ethylbenzene concentration of 9.5 µg/L, para-xylene concentration of 5.3 µg/L, and meta-xylene concentration of
Six samples of industrial waste water with 11.6 µg/L, ortho-xylene concentration of 19.4 µg/L, and styrene concentration of 19.4 µg/L were performed 6 times.
Repeated spiking analysis and determination, spiking concentration is 6000 μg/L. average spiking recovery range is 84.5% ～ 103%;
The final yield range was 87.0% ± 5.9% ～ 96.7% ± 8.8%.
For precision and accuracy results, see Tables C.1 to C.4 in Appendix C.
10 Quality Assurance and Quality Control
10.1 Blank test
Every 20 samples or each batch of samples (< 20/batch) should have at least one full program blank and one laboratory blank.
The concentration of the target substance in the measurement results should be lower than the detection limit of the method.
10.2 Calibration
Before analyzing samples, a working curve covering at least 5 concentration points covering the sample concentration range should be established.
The number should be ≥0.995. Otherwise, find the cause and redraw the working curve.
In continuous analysis, the concentration point in the middle of the working curve is analyzed every 24 hours. The relative error between the measurement result and the known concentration is
The difference should be within ± 20%. Otherwise, the working curve must be re-established.
610.3 Precision and accuracy
10.3.1 Every 20 samples or each batch of samples (< 20 samples/batch) should be analyzed for 1 parallel sample, the parallel sample measurement results are relatively biased
The difference should be ≤20%.
10.3.2 Every 20 samples or each batch of samples (< 20 samples/batch) should be analyzed for 1 matrix spiked sample, and the matrix spiked recovery rate should be
Controlled between 70% and 130%.
11 Waste treatment
Wastes generated during the experiment should be collected separately, stored centrally, and entrusted to a qualified unit for disposal.
12 Notes
12.1 During sampling, sample storage and pretreatment, avoid contact with plastics and other organic materials.
12.2 When measuring samples with high salt content, the amount of sodium chloride (4.3) can be reduced to avoid salt precipitation in the sample
This causes a change in the gas-liquid two-phase volume in the headspace vial. The amount of salt added to the sample and the standard series should be the same.
7 Appendix A
(Normative appendix)
Detection limit and lower detection limit of the target compound
Table A.1 shows the detection limit and the lower detection limit of the method when the sampling volume is 10.0 ml.
Table A.1 Detection limits and determination limits for target compounds
Substance name detection limit (µg/L) Lower detection limit (µg/L)
Benzene 2 8
Toluene 2 8
Ethylbenzene 2 8
P-xylene 2 8
M-xylene 2 8
Cumene 3 12
O-xylene 2 8
Styrene 3 12
8 Appendix B
(Informative appendix)
Auxiliary qualitative reference chromatogram
Refer to Figure B.1 for the reference chromatogram of the separation of benzenes using column II (5.4) according to the instrument reference conditions (7.1).
1-methanol; 2-benzene; 3-toluene; 4-ethylbenzene; 5-p-, m-xylene; 6-o-xylene, styrene; 7-cumene.
Figure B.1 Reference chromatogram of benzene series (column II auxiliary characterization) (6000 µg/L)
min5 10 15 20 25 30
pA
FID1 A, front signal (pyridine.2017 \\ pyridine double column test-DB624.2017-07-27 11-31-47 \\ 17072707.D)
9 Appendix C
(Informative appendix)
Method precision and accuracy
Tables C.1 to C.4 give the precision and accuracy of the methods, respectively.
Table C.1 Precision of 6 laboratory methods
Substance name Benzene ethylbenzene p-xylene meta-xylene cumene o-xylene styrene
20 µg/L
Measured average
(Μg/L)
20 19 19 19 20 19 20 19
Relative in the laboratory
standard deviation(%)
3.0 ～ 13 4.1 ～ 15 4.1 ～ 9.4 4.9 ～ 12 4.4 ～ 12 4.1 ～ 15 3.6 ～ 12 1.6 ～ 14
Interlaboratory
standard deviation(%)
8.2 9.8 11 11 12 11 9.5 8.2
Repeatability limit r
(Μg/L)
Reproducibility limit R
(Μg/L)
100 µg/L
Measured average
(Mg/L)
97 96 96 94 96 96 96 96
Relative in the laboratory
standard deviation(%)
2.1 ～ 6.1 3.0 ～ 6.0 2.9 ～ 8.9 4.5 ～ 7.7 2.6 ～ 7.2 4.4 ～ 9.5 3.1 ～ 6.4 3.8 ～ 6.3
Interlaboratory
standard deviation(%)
3.9 3.8 4.4 5.3 4.2 5.6 3.1 2.7
Repeatability limit r
(Μg/L)
12 14 15 15 14 19 14 14
Reproducibility limit R
(Μg/L)
16 16 18 19 17 23 15 14
Table C.2 Precision of 1 laboratory method
Substance name Benzene ethylbenzene p-xylene meta-xylene cumene o-xylene styrene
50 µg/L
Measured average
(Μg/L)
52 55 51 53 51 51 48 49
Relative in the laboratory
standard deviation(%)
6.3 5.6 8.5 8.4 7.2 9.2 7.7 6.0
2000 µg/L
Measured average
(Μg/L)
2.02 × 103 2.04 × 103 1.91 × 103 2.07 × 103 2.07 × 103 2.08 × 103 2.06 × 103 2.05 × 103
Relative in the laboratory
standard deviation(%)
2.9 4.8 7.0 7.4 7.2 7.8 6.0 4.7
10000 µg/L
Measured average
(Μg/L)
9.95 × 103 9.96 × 103 9.99 × 103 10.0 × 103 9.99 × 103 9.99 × 103 9.99 × 103 10.0 × 103
Relative in the laboratory
standard deviation(%)
2.6 2.4 2.1 2.1 2.1 1.9 2.1 2.5
Table C.3 Accuracy of 6 laboratory methods
Sample type compounds
Sample concentration
(Μg/L)
Spiked concentration
(Μg/L)
Spike recovery
range(%)
Final spike recovery
P ± 2 PS (%)
Surface water
Benzene 0 100 85.9 ～ 119 105 ± 24.2
Toluene 0 100 92.5 ～ 120 105 ± 20.4
Ethylbenzene 0 100 94.2 ～ 120 105 ± 19.6
P-xylene 0 100 95.7 ～ 121 105 ± 19.8
M-xylene 0 100 90.8 ～ 122 104 ± 21.4
Cumene 0 100 88.4 ～ 122 103 ± 26.8
O-xylene 0 100 94.2 ～ 111 102 ± 13.0
Styrene 0 100 100 ～ 113 106 ± 11.0
Table C.4 Accuracy of 1 laboratory method
Sample type compounds
Sample concentration
(Μg/L)
Spiked concentration
(Μg/L)
Spike recovery
range(%)
Final spike recovery
P ± 2 PS (%)
groundwater
Benzene 0 500 84.4 ～ 91.6 88.4 ± 6.0
Toluene 0 500 81.6 ～ 89.4 86.6 ± 5.4
Ethylbenzene 0 500 79.6 ～ 88.8 85.5 ± 6.7
Paraxylene 0 500 79.4 ～ 88.8 85.4 ± 7.0
M-xylene 0 500 79.6 ～ 88.4 85.3 ± 6.6
Cumene 0 500 78.4 ～ 88.6 84.6 ± 7.8
O-xylene 0 500 80.8 ～ 89.2 86.1 ± 6.1
Styrene 0 500 82.2 ～ 89.8 86.8 ± 5.6
domestic sewage
Benzene 0 1000 80.2 ～ 84.3 82.2 ± 2.8
Toluene 0 1000 78.3 ～ 85.4 81.1 ± 5.0
Ethylbenzene 0 1000 77.0 ～ 86.2 80.3 ± 6.9
Paraxylene 0 1000 77.6 ～ 87.2 81.0 ± 7.2
M-xylene 0 1000 77.6 ～ 87.1 81.0 ± 7.2
Cumene 0 1000 76.1 ～ 86.6 80.1 ± 7.8
O-xylene 0 1000 80.6 ～ 89.0 83.5 ± 6.4
Styrene 0 1000 85.2 ～ 92.6 87.6 ± 5.7
Continued
Sample type compounds
Sample concentration
(Μg/L)
Spiked concentration
(Μg/L)
Spike recovery
range(%)
Final spike recovery
P ± 2 PS (%)
Industrial waste
Benzene 0 6000 91.4 ～ 103 96.7 ± 8.8
Toluene 0 6000 90.3 ～ 102 95.1 ± 8.6
Ethylbenzene 9.5 6000 88.2 ～ 98.2 91.6 ± 7.8
Paraxylene 5.3 6000 88.0 ～ 97.8 91.3 ± 7.6
M-xylene 11.6 6000 88.0 ～ 98.4 91.4 ± 7.9
Cumene 0 6000 84.5 ～ 92.5 87.0 ± 5.8
O-xylene 19.4 6000 90.0 ～ 98.4 92.5 ± 6.6
Styrene 19.4 6000 92.4 ～ 101 95.0 ± 6.4
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