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HJ 686-2014 English PDF

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HJ 686-2014: Water quality. Determination of volatile organic compounds. Purge and trap/gas chromatography
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HJ 686-2014	English	449	Add to Cart	3 days [Need to translate]	Water quality. Determination of volatile organic compounds. Purge and trap/gas chromatography	Valid	HJ 686-2014

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Basic data

Standard ID	HJ 686-2014 (HJ686-2014)
Description (Translated English)	Water quality. Determination of volatile organic compounds. Purge and trap/gas chromatography
Sector / Industry	Environmental Protection Industry Standard
Classification of Chinese Standard	Z16
Word Count Estimation	17,167
Quoted Standard	HJ/T 91; HJ/T 164
Regulation (derived from)	Department of Environmental Protection Notice No. 4 of 2014
Issuing agency(ies)	Ministry of Ecology and Environment
Summary	This Standard specifies the determination of 21 kinds of volatile organic compounds in water by purge and trap/gas chromatography. This Standard applies to surface water, groundwater measured organics, sewage and industrial wastewater volatility. When the

HJ 686-2014: Water quality. Determination of volatile organic compounds. Purge and trap/gas chromatography

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Water quality.Determination of volatile organic compounds.Purge and trap/gas chromatography National Environmental Protection Standard of the People's Republic Determination of volatile organic compounds in water Purge trapping/gas chromatography Water quality-Determination of volatile organic compounds- Purge and trap/gas chromatography Published on January 13,.2014 2014-4-1 implementation Ministry of Environmental Protection released

Content

Preface II 1 Scope..1 2 Normative references..1 3 method principle..1 4 interference and elimination.1 5 Reagents and materials.1 6 instruments and equipment.2 7 samples.3 8 Analysis steps..3 9 result calculation and representation..5 10 Precision and Accuracy 5 11 Quality Control and Quality Assurance..6 12 Disposal of waste.7 13 Notes 7 Appendix A (Normative) method for detection limits and lower limit of determination 9 Appendix B (informative) method of precision and accuracy..10

Foreword

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 Prevention and Control, to protect the environment, This standard is formulated to ensure human health and to regulate the determination of volatile organic compounds in water. This standard specifies the determination of the extraction, capture and gas of volatile organic compounds in surface water, groundwater, domestic sewage and industrial wastewater. Phase chromatography. This standard is the first release. Appendix A of this standard is a normative appendix, and Appendix B is an informative appendix. This standard was formulated by the Science and Technology Standards Department of the Ministry of Environmental Protection. This standard is mainly drafted by. China Environmental Monitoring Center, Jiangsu Environmental Monitoring Center. This standard is verified by. Taizhou Environmental Monitoring Center Station, Sichuan Environmental Monitoring Center Station, and Liaoning Province Environmental Monitoring Inspection Center, Dalian Environmental Monitoring Center, Ningbo Environmental Monitoring Center and Changzhou Environmental Monitoring Center. This standard was approved by the Ministry of Environmental Protection on January 13,.2014. This standard has been implemented since April 1,.2014. This standard is explained by the Ministry of Environmental Protection. Water quality - Determination of volatile organic compounds - Sw Warning. The chemicals used in this method are harmful to human health, and protective equipment should be worn as required during operation. Avoid contact with skin and clothing. All standard samples, reagents, etc. should be completely sealed and stored separately, and placed in a cool, cool place. In order to avoid leakage of pollution.

1 Scope of application

This standard specifies the purge and trap/gas chromatography for the determination of 21 volatile organic compounds in water. This standard applies to the determination of volatile organic compounds in surface water, groundwater, domestic sewage and industrial wastewater. When sampling When the concentration is 5 ml, the detection limit of the target compound is 0.1-0.5 μg/L, and the lower limit of determination is 0.4-2.0 μg/L. See Appendix A for details of compound and detection limits. Other volatile organic compounds may also be analyzed by this method after verification of suitability.

2 Normative references

The contents of this standard refer to the following documents or their terms. For undated references, the valid version is appropriate. Used in this standard. HJ/T 91 Surface Water and Wastewater Monitoring Technical Specifications HJ/T 164 Technical Specifications for Groundwater Environmental Monitoring

3 Principle of the method

The volatile organic compounds in the sample are adsorbed in the trap tube after being purged with high-purity nitrogen, and the trap tube is heated and high-purity nitrogen gas. Backflushing, the thermally desorbed components are separated by gas chromatography and ionized by an electron capture detector (ECD) or hydrogen flame. The detector (FID) is tested and characterized by retention time and by external standard method.

4 interference and elimination

4.1 Interfering agents for the analysis of volatile organic compounds by laboratory solvents, reagents, glassware and other components used for pretreatment, It can be tested by laboratory blanks. When you find that the laboratory analysis process does interfere with the sample, you should look carefully The source of the disturbance is eliminated in time, and the sample analysis can be continued only after the laboratory blank inspection and analysis is passed. 4.2 During the process of sampling, shipping and storage, volatile organic compounds in the air will be contaminated by the diffusion of the seal of the sampling bottle. It can be checked by a full program blank. Care should be taken when the sampling, shipping or storage process does interfere with the sample. Look for interference sources. If there is interference that affects the analysis results, you need to re-sample the analysis. 4.3 Alternate analysis of high concentration samples and low concentration samples may cause interference. When analyzing a high concentration sample, analyze one. Blank samples to check for cross contamination.

5 reagents and materials

Unless otherwise stated, analytically pure reagents and distilled water in accordance with national standards were used for the analysis. 5.1 blank reagent water Secondary distilled water or water prepared by pure water equipment, passed the test without the target combination of the method detection limit (MDL) When the substance is detected, it can be used as a blank reagent water. It can be removed by heating or boiling with inert gas to remove volatilization from water. Sexual organic matter interferes. 5.2 Methanol (CH3OH) Agricultural residue level, used to prepare standard samples. Different batches of methanol are subjected to blank inspection. The test method is to take 20μl of methanol to join In the blank reagent water, the analysis was carried out under exactly the same conditions as the actual sample analysis. 5.3 Standard stock solution. ρ = 100μg/ml. The standard stock solution of volatile organic compounds should be stored in the dark and should be used as soon as possible after opening. Such as the storage liquid after opening Storage should be stored frozen at -10 to -20 °C. The stock solution to be stored should be tested before use, if compound response is found If the value or type is abnormal, discard it and use it to restore room temperature. 5.4 Standard intermediate solution for gas chromatography analysis. ρ = 20 μg/ml. According to the sensitivity and linearity requirements of the instrument, take appropriate amount of standard stock solution (5.3) and dilute with methanol (5.2) to prepare The concentration is generally 20.0 μg/ml, and the storage time is one month. 5.5 Ascorbic acid (C6H8O6) 5.6 hydrochloric acid solution, 1 1 5.7 Gas Nitrogen, purity ≥99.999%; or helium, purity ≥99.999%; hydrogen, purity ≥99.999%; air, ordinary compression Air or high purity air.

6 Instruments and equipment

Unless otherwise stated, the analysis uses a Class A glass gauge that complies with national standards. 6.1 Gas Chromatograph. Configure an Electronic Capture Detector (ECD) or Hydrogen Flame Detector (FID). 6.2 Purge the trap. Type of packing for purging and trapping traps. 1/3 carbon fiber, 1/3 silica gel and 1/3 activated carbon homogeneously mixed filler or other Effective adsorbent. 6.3 Column Type. 6.3.1 Determination of benzene series. quartz capillary column, 30m (length) × 320μm (inside diameter) × 0.50μm (film thickness), fixed The phase is polyethylene glycol. Other equivalent capillary columns can also be used. 6.3.2 Determination of halogenated hydrocarbons. quartz capillary column, 30m (length) × 320μm (inside diameter) × 1.80μm (film thickness), fixed The phase is 6% cyanopropylbenzene-94% dimethylpolysiloxane. Other equivalent capillary columns can also be used. 6.4 Vials. 40ml brown glass bottle, screw cap (with Teflon coated gasket). 6.5 5ml airtight syringe. 6.6 Microinjector. 10 μl, 100 μl. 6.7 Volumetric flask. Class A, 50ml

7 samples

7.1 Sample collection Sample collection of groundwater, surface water and sewage is carried out in accordance with the relevant provisions of HJ/T 164 and HJ/T 91, respectively. all Samples were collected in parallel and each sample should have a full program blank and a transport blank. Note 1. The sampling bottle should be thoroughly cleaned before sampling, and the sample should not be washed with water. 7.2 Preservation of samples The collected samples should be analyzed as soon as possible. If it is necessary to save, measures should be taken. See Table 1 for the preservation measures in various situations. Table 1 Sample preservation measures Sample property container preservation method storage time No residual chlorine 40ml brown glass bottle 0.5ml hydrochloric acid solution, stored at 4 ° C for 14 days Residual chlorine 40ml brown glass bottle Add about 25mg of ascorbic acid, plus 0.5ml Hydrochloric acid solution, stored at 4 ° C 14 days 7.3 Preparation of samples 7.3.1 Purge and trap system without autosampler. 5 ml sample is taken from the vial with a 5 ml airtight syringe, push-in Sweep the collector purge tube for purging and trapping. 7.3.2 Purge and Trap System with Autosampler. Place the 40ml vial directly into the autosampler sample cell and set it up. The sample volume was 5 ml and was purged and trapped. Note 2. All samples (including the entire blank) must be reached at room temperature for analysis. Note 3. When analyzing samples, first analyze blank samples, such as blanks in the whole process, laboratory blanks, etc.

8 Analysis steps

8.1 Instrument Reference Conditions 8.1.1 Purge and trap conditions The purge and trap reference conditions are shown in Table 2. Table 2 Purge and trap reference conditions Purge temperature purge flow rate purge time desorption temperature desorption time baking temperature baking time dry blowing time Normal temperature 40ml/min 11min 180°C 2min 250°C 10min 2min 8.1.2 GC-FID/ECD Analysis Reference Conditions 8.1.2.1 Gas chromatographic section (FID as detector) Temperature programmed. 40 ° C (for 6 min) 5/min ⎯⎯⎯ → ° C 100 ° C (for 2 min) 5/min ⎯⎯⎯ → ° C.200 ° C; inlet Temperature..200 ° C; detector temperature. 280 ° C; carrier gas flow rate. 2.5 ml/min; split ratio. 10. 1 or according to instrument conditions. 8.1.2.2 Gas Chromatography section (ECD as detector) Temperature programmed. 40 ° C (for 6 min) 5/min ⎯⎯⎯ → ° C 100 ° C (for 2 min) 5/min ⎯⎯⎯ → ° C.200 ° C; inlet Temperature..200 ° C; detector temperature. 280 ° C; carrier gas flow rate. 2.5 ml/min; split ratio. 10. 1 or according to instrument conditions. 8.2 Calibration The calibration curve needs to be drawn when the instrument is used for the first time, or when the instrument is repaired, column changed, or continuously calibrated. 8.2.1 Preparation of the standard series The linear range of the method is 0.5~200μg/L According to the sensitivity and linearity requirements of the instrument and the concentration of the actual sample, take a suitable amount of standard intermediate solution (5.4) with a blank test. The reagent water (5.1) is prepared to the corresponding standard concentration sequence. Benzene series. low concentration standard series are 0.5μg/L, 1.0μg/L, 2.0μg/L, 5.0μg/L, 10.0μg/L and 20.0μg/L, The high concentration standard series is 5.0μg/L, 20.0μg/L, 50.0μg/L, 100μg/L,.200μg/L (both reference concentration sequences). Now available. Halogenated hydrocarbons. low concentration standard series. 0.05μg/L, 0.20μg/L, 0.50μg/L, 2.0μg/L, 5.0μg/L and 10.0μg/L, High concentration standard series are 0.5μg/L, 2.0μg/L, 10.0μg/L, 20.0μg/L, 50.0μg/L and.200μg/L (both are reference thick) Degree sequence), now available. Note 4. The concentration range of the standard series should be adjusted according to the actual sample. The highest concentration point is not higher than.200μg/L, and the correlation coefficient should be r≥0.995. 8.2.2 Drawing of the calibration curve Transfer a certain amount of standard intermediate solution (5.4) to the volumetric flask (6.7) containing the blank reagent water (5.1). Make up to the mark line and shake the volumetric flask three times vertically to mix evenly. Take 5.0ml standard curve series solution in the purge tube, after purging, collecting and concentrating, then enter the gas chromatographic analysis. To correspond to different concentrations of gas chromatograms. The calibration curve is drawn with the peak height or peak area as the ordinate and the concentration as the abscissa. 8.2.3 Standard chromatogram The target compound reference spectrum is shown in Figures 1 and 2, depending on the detector type. Figure 1 is the ECD detection of halogenated hydrocarbons. The gas chromatogram, Figure 2 is the gas chromatogram of the benzene species detected by FID. 1-1,1-dichloroethylene; 2-dichloromethane; 3-trans-1,2-dichloroethylene; 4-chlorobutadiene; 5-cis-1,2-dichloroethylene; -chloroform; 7 - carbon tetrachloride; 8-1,2-dichloroethane; 9-trichloroethylene; 10-epoxychloropropane; 11-tetrachloroethylene; 12-bromoform; 13-hexachlorobutadiene Figure 1 ECD detector analysis of the gas chromatogram of the target component of 5.0μg/L halogenated hydrocarbon Min5 10 15 20 25 Hz Partial enlargement See right 1-benzene; 2-toluene; 3-ethylbenzene; 4-p-xylene; 5-m-xylene; 6-isopropylbenzene; 7-o-xylene; 8-styrene Figure 2 FID detector analysis and analysis of the gas chromatogram of the target component of 5.0μg/L benzene series 8.3 Determination Take 5ml samples and analyze them according to the same analytical conditions of standard samples, record the retention time of each component peak and Peak height (or peak area). 8.4 Blank test While the sample is being analyzed, a blank test should be performed. Take 5ml blank sample (5.1) into the gas chromatograph, press 8.3 The steps are analyzed.

9 Calculation and representation of results

9.1 qualitative results Qualitative analysis was performed based on the retention times of the components of the reference material. 9.2 Quantitative results Quantitative by external standard method, the unit is μg/L. The calculated result is 1 bit after the decimal point when the measured value is less than 100 μg/L; When the value is 100μg/L or more, 3 significant digits are reserved. 10 Precision and accuracy 10.1 Precision Six laboratories for uniform samples containing benzene-based volatile organic compounds at concentrations of 0.5 μg/L, 10 μg/L and 20 μg/L Measured, The relative standard deviations in the experimental room were. 1.7% to 15.9%, 1.9% to 8.5%, and 1.2% to 8.4%, respectively; The relative standard deviations between laboratories are. 6.2% to 16.8%, 5.2% to 10.1%, and 1.8% to 3.8%; The repeatability limits are. 0.07μg/L to 0.12μg/L, 0.82μg/L to 1.58μg/L, and 1.95μg/L to 2.90μg/L; The reproducibility limits were 0.14 μg/L to 0.23 μg/L, 1.66 μg/L to 2.83 μg/L, and 2.32 μg/L to 3.01 μg/L, respectively. Six laboratories for uniform samples containing halogenated hydrocarbon volatile organic compounds at concentrations of 0.2μg/L, 1.0μg/L and 10μg/L Measured, The relative standard deviations in the experimental room were. 2.4% to 18.2%, 0.7% to 11.4%, and 1.2% to 11.5%; The relative standard deviations between laboratories were. 2.9% to 9.8%, 1.6% to 5.5%, and 1.5% to 3.2%, respectively; The repeatability limits are. 0.04μg/L to 0.06μg/L, 0.11μg/L to 0.19μg/L, and 0.77μg/L to 1.84μg/L; The reproducibility limits were. 0.05 μg/L to 0.07 μg/L, 0.13 μg/L to 0.22 μg/L, and 0.87 μg/L to 1.89 μg/L, respectively. Six laboratories tested uniform samples containing epichlorohydrin concentrations of 1.0 μg/L, 5.0 μg/L, and 50.0 μg/L. The relative standard deviations in the experimental room were. 5.0% to 11.3%, 2.9% to 7.8%, and 2.4% to 5.9%, respectively; The relative standard deviations between laboratories were. 2.9%, 3.3%, and 3.3%, respectively; The repeatability limits were. 0.22 μg/L, 0.74 μg/L and 5.69 μg/L, respectively; Reproducibility limits were. 0.23 μg/L, 0.82 μg/L, and 6.85 μg/L, respectively. The repeatability and reproducibility results are shown in Table B.1. 10.2 Accuracy The six laboratories added the standard amount of surface water, industrial wastewater and domestic wastewater to the spiked amount of 0.2-100μg/L. In the recovery experiment, the average spiked recovery was 90.3% to 101.5%, and the results are shown in Table B.2. 11 Quality Control and Quality Assurance The following quality control and assurance measures are selected based on the actual needs of the analysis. 11.1 Blank analysis 11.1.1 Laboratory blank In the laboratory blank analysis results, the concentration of all target compounds to be tested should be lower than the method detection limit. When found empty When the concentration of one or some of the target compound components in white is higher than the method detection limit, all possible laboratory empty White-related effects, such as reagents, solvents, standard samples, glassware, and other components used for pretreatment. Look carefully for the source of interference and eliminate it in time. After the laboratory blank test analysis is passed, the sample analysis can be continued. 11.1.2 Shipping blank A blank reagent water is placed in the vial and sealed in the laboratory prior to sampling to bring it to the site. Cap on the bottle when sampling Always in a sealed state, transported to the laboratory with the sample, processed and measured in the same analytical step as the sample, for inspection Check if the sample is contaminated during transportation. 11.1.3 Full program blank A blank reagent water is placed in the vial and sealed in the laboratory prior to sampling to bring it to the site. Sample bottle with sample Simultaneously open the lid and seal, transport the sample back to the laboratory, and process and measure according to the same analytical steps as the sample for inspection. Whether the sample is collected and analyzed for pollution. If the target compound is above the detection limit in the full program blank, the blank value cannot be deducted from the sample result. Should check all Look for sources of influence on the entire program gap and look for sources of interference. If you do find the sampling, transportation or preservation process There are interferences that affect the results of the analysis, and samples from the problem batches need to be resampled. 11.2 Determination of parallel samples Although each sample is sampled in parallel, typically one analysis is performed for every 10 samples or batches (less than 10 samples/batch). For parallel samples, the relative deviation of the parallel sample measurements is less than 20%. Note 6. In view of the specificity of volatile organic compounds, the samples in each vial are only allowed to be analyzed once without parallel analysis in the room. 11.3 Determination of blank spikes Blank spiked assays typically require a blank plus for every 10 samples or batches (less than 10 samples/batch) Mark, the recovery rate is between 70% and 120%. If the recovery rate of the blank addition cannot meet the quality control requirements, the cause should be ascertained until the recovery rate meets the quality control requirements. After that, sample analysis can be continued. 11.4 Determination of sample spikes For the spiked sample, it is generally required to analyze one spike for every 10 samples or batches (less than 10 samples/batch). The recoveries of the spiked samples ranged from 70% to 120%. If the recovery of the sample spike does not meet the quality control requirements, then another sample spiked parallel test should be performed. If the measurement result is consistent with the previous sample spiked test result, it indicates that the matrix interference of the sample exists, the above analysis The data can be used normally. If the measurement result of the parallel addition of the sample does not coincide with the result of the previous sample addition, it indicates that If there is a problem in the analysis process, the sample spike analysis should be repeated until the sample spike recovery meets the experiment. Room quality control requirements. 11.4 Calibration 11.4.1 Initial calibration Initial calibration is required when the instrument is first used, or when the instrument is repaired, the column is replaced, or the continuous calibration fails. That is, a calibration curve is established. The correlation coefficient of the calibration curve is ≥0.995, otherwise the calibration curve should be redrawn. 11.4.2 Continuous calibration When using the initial calibration curve for each batch of sample test, a certain concentration of standard sample must be used first (recommended initial calibration) The intermediate concentration point or the second highest concentration point of the curve is quantitatively determined according to the same instrumental analysis conditions determined by the sample. If the relative deviation between the measurement result and the sample concentration is ≤20%, the initial calibration curve can be extended; if any compound is relatively biased The difference is >20%. The reason should be found and measures should be taken. If the measures are taken, the relative deviation of the measurement cannot be achieved. Make a new standard curve. Perform a continuous calibration analysis for every 20 samples or batches (less than 20 samples/batch) to verify the initial standard Whether the line continues to apply. 12 Waste treatment The laboratory shall be responsible for the collection, treatment and management of hazardous wastes, and shall be provided according to the type of waste. The collection container should be clearly marked on the collection container. Corresponding protective facilities and treatment procedures should be established for the collected waste. 13 Precautions 13.1 The interference of benzene series determination mainly comes from the tailing of methanol peak, which affects the determination of benzene, so the sample analysis process should be completed A small amount of methanol is introduced. 13.2 When the sample is collected, it should be filled with the sampling bottle. No gap is required. It is forbidden to open the bottle after sampling and analyze as soon as possible. 13.3 Due to the high volatility of the target compound, do not perform solution preparation in the fume hood to avoid volatilization. The effect of sample determination. 13.4 Encountering foamed samples (such samples are not only difficult to analyze accurately, but the resulting foam will stain or block the pipeline, Valves, adsorption tubes, etc., which adversely affect the subsequent analysis of the sample), may optionally be added to the defoamer or A disposal method such as a defoaming device is added to the purge device.

Appendix A

(normative appendix) Method detection limit and lower limit of determination Table A The detection limit and lower limit of the method No. Component Name Target Compound English Name CAS No. Detector Detection limit (μg/L) (μg/L) 1 Benzene Benene 107-06-2 FID 0.5 2.0 2 Toluene Toluene 108-88-3 FID 0.5 2.0 3 ethylbenzene Ethylbenzene 100-41-4 FID 0.5 2.0 4 p-xylene p-Xylene 108-38-3 FID 0.5 2.0 5 m-xylene m-Xylene 106-42-3 FID 0.5 2.0 6 o-xylene o-Xylene 95-47-6 FID 0.5 2.0 7 Styrene Styrene 100-42-5 FID 0.5 2.0 8 cumene Isopropylbenzene 98-82-8 FID 0.5 2.0 9 1,1-Dichloroethylene 1,1-Dichloroethene 75-35-4 ECD 0.1 0.4 10 1,2-Dichloroethane 1,2-Dichloroethane 71-43-2 ECD 0.1 0.4 11 Dichloromethane 1975/9/2 ECD 0.5 2.0 12 trans-1,2-dichloroethylene Trans-1,2-Dichloroethene 594-20-7 ECD 0.1 0.4 13 Hexachlorobutadiene 87-68-3 ECD 0.1 0.4 14 chloroprene 2-Chloro-1,3-butadiene 126-99-8 ECD 0.1 0.4 15 Trichloromethane Choroform 67-66-3 ECD 0.1 0.4 16 Trichloroethene 1979/1/6 ECD 0.1 0.4 17 Tribromomethane Bromoform 75-25-2 ECD 0.1 0.4 18 cis-1,2-dichloroethylene Cis-1,2-Dichloroethene 156-60-5 ECD 0.1 0.4 19 Carbon Tetrachloride Carbon Tetrachloride 56-23-5 ECD 0.1 0.4 20 Tetrachloroethene 127-18-4 ECD 0.1 0.4 21 Epichlorohydrin Epichlorohydrin 106-89-8 ECD 0.5 2.0

Appendix B

(informative appendix) Method precision and accuracy Table B.1 Precision measured by six laboratories Serial number compound name ...

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