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HJ 642-2013: Soil and sediment. Determination of volatile organic compounds-Headspace-gas chromatography/mass method
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Soil and sediment. Determination of volatile organic compounds-Headspace-gas chromatography/mass method
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HJ 642-2013
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Standard similar to HJ 642-2013 HJ 644 HJ 662 HJ 298 HJ 950 HJ 643 Basic data | Standard ID | HJ 642-2013 (HJ642-2013) | | Description (Translated English) | Soil and sediment. Determination of volatile organic compounds-Headspace-gas chromatography/mass method | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z13 | | Classification of International Standard | 13.080 | | Word Count Estimation | 19,168 | | Quoted Standard | GB 17378.3; GB 17378.5; HJ 613; HJ/T 166 | | Regulation (derived from) | ?Ministry of Environmental Protection Announcement 2013 No. 6 | | Issuing agency(ies) | Ministry of Ecology and Environment | | Summary | This standard specifies the headspace measurement of volatile organic compounds in soil and sediment in/gas chromatography-mass spectrometry. This standard applies to 36 kinds of soil and sediment determination of volatile organic compounds. If validated, | HJ 642-2013: Soil and sediment. Determination of volatile organic compounds-Headspace-gas chromatography/mass method
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Soil and sediment.Determination of volatile organic compounds-Headspace-gas chromatography/mass method
National Environmental Protection Standard of the People's Republic
Determination of volatile organic compounds in soils and sediments
Headspace/gas chromatography-mass spectrometry
Soil and sediment-Determination of volatile organic compounds-
Headspace-gas chromatography/mass method
Published on.2013-01-21
2013-07-01 Implementation
Ministry of Environmental Protection released
Content
Foreword. II
Warning..1
1 Scope..1
2 Normative references..1
3 Terms and Definitions.1
4 principle of the method..2
5 reagents and materials. 2
6 instruments and equipment.3
7 samples.3
8 Analysis steps..4
9 Results calculation and representation..7
10 precision and accuracy..8
11 Quality Assurance and Quality Control 9
12 Waste treatment 10
13 Notes 10
The detection limit and lower limit of determination of Appendix A (normative appendix) method 11
Appendix B (informative) Determination of target compounds. Reference parameters. 12
Appendix C (informative) method of precision and accuracy. 14
Foreword
To implement the Environmental Protection Law of the People's Republic of China, protect the environment, protect human health, and regulate soil and sediment
This standard is developed for the determination of volatile organic compounds.
This standard specifies headspace/gas chromatography-mass spectrometry for the determination of volatile organic compounds in soils and sediments.
This standard is the first release.
Appendix A of this standard is a normative appendix, and Appendix B and Appendix C are informative appendices.
This standard was formulated by the Science and Technology Standards Department of the Ministry of Environmental Protection.
This standard is mainly drafted by. Anshan Environmental Monitoring Center Station, Environmental Protection Institute of the Ministry of Environmental Protection.
This standard is verified by. Liaoning Provincial Environmental Monitoring Experimental Center, Shenyang Environmental Monitoring Center Station, Dalian Environmental Monitoring
Center, Harbin Environmental Monitoring Center Station, Fushun Environmental Monitoring Center Station and Liaoyang Environmental Monitoring Center Station.
This standard was approved by the Ministry of Environmental Protection on January 21,.2013.
This standard has been implemented since July 1,.2013.
This standard is explained by the Ministry of Environmental Protection.
Determination of volatile organic compounds in soils and sediments
Headspace/gas chromatography-mass spectrometry
Warning. The internal standard, substitute and standard solution used in the test are volatile toxic compounds, and the solution preparation process should be
Operate in a fume hood; wear protective gear as required to avoid contact with skin and clothing.
1 Scope of application
This standard specifies headspace/gas chromatography-mass spectrometry for the determination of volatile organic compounds in soils and sediments.
This standard applies to the determination of 36 volatile organic compounds in soils and sediments. If verified, this standard can also be adapted
Used for the determination of other volatile organic compounds.
When the sample amount is 2g, the detection limit of 36 targets is 0.8~4μg/kg, and the lower limit is 3.2~14μg/kg.
See Appendix A for details.
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.
GB 17378.3 Marine monitoring specification Part 3 Sample collection, storage and transportation
GB 17378.5 Marine monitoring specification Part 5 Sediment analysis
HJ 613 Determination of dry matter and moisture in soils - Gravimetric method
HJ/T 166 Technical Specifications for Soil Environmental Monitoring
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Internal standard
Refers to a substance that is not contained in the sample but has similar physicochemical properties to the target to be tested. Usually added before sample analysis
In, for the quantification of the target.
3.2
Surrogate
Refers to a substance that is not contained in the sample but has similar physicochemical properties to the target to be tested. Generally in sample extraction or other
Before the pretreatment, the recovery rate can be used to evaluate the influence of the sample matrix and the sample processing process on the analysis results.
3.3
Matrix spiked spike
It means that a known amount of the target to be tested is added to the sample for evaluating the recovery rate of the target and the matrix effect of the sample.
3.4
Calibration verification standards
Refers to a standard solution with a concentration near the midpoint of the calibration curve to confirm the validity of the calibration curve.
3.5
Transport blank strip blank
10 ml matrix modifier and 2.0g quartz sand were placed in the headspace bottle for sealing before sampling, and brought to the sampling
field. The sample is not opened when it is sampled, and then shipped back to the laboratory with the sample, and the experiment is performed in the same analysis step as the sample for inspection.
Whether the sample is contaminated during transportation.
3.6
Full program blank whole program blank
10 ml matrix modifier and 2.0g quartz sand were placed in the headspace bottle for sealing before sampling, and brought to the sampling
field. Simultaneously open and seal the sample vial, then transport it back to the laboratory with the sample, and follow the same analysis steps as the sample.
An experiment is performed to check whether the entire process from sample collection to analysis is contaminated.
4 Principle of the method
Under certain temperature conditions, the volatile components in the sample in the headspace bottle volatilize into the liquid space to generate vapor pressure.
The liquid-solid three-phase reaches the thermodynamic dynamic equilibrium. The volatile organic compounds in the gas phase are separated by gas chromatography and then mass spectrometer
Detection. Qualitative by comparison with standard material retention times and mass spectra, quantified by internal standard method.
5 reagents and materials
5.1 Experimental water. double distilled water or water prepared by pure water equipment. A blank test is required before use to confirm the target
There is no interference peak in the retention time interval of the object or the concentration of the target therein is lower than the detection limit of the method.
5.2 Methanol (CH3OH). Chromatographic grade, pass the test before use to confirm the concentration of target compound or target compound
Below the method detection limit.
5.3 Sodium chloride (NaCl). excellent grade pure
After burning at 400 ° C for 4 h in a muffle furnace, it was placed in a desiccator and cooled to room temperature, and transferred to a ground glass bottle for storage.
5.4 Phosphoric acid (H3PO4)). excellent grade pure.
5.5 Matrix modifier
Measure 500ml of experimental water (5.1), add a few drops of phosphoric acid (5.4) to adjust pH ≤ 2, add 180g of sodium chloride (5.3),
Dissolve and mix. Store at 4 ° C for 6 months.
5.6 Standard stock solution. ρ=1000 mg/L～5000 mg/L
Standard certified solutions can be purchased directly or in standard materials.
5.7 Standard use solution. ρ=10 mg/L～100 mg/L.
Volatile targets such as dichloromethane, trans-1,2-dichloroethylene, 1,2-dichloroethane, cis-1,2-dichloroethylene and chloroacetate
Standard intermediates such as olefins must be prepared separately, and the storage period is usually one week. The standard use solution of other targets is stored in compact.
The shelf life is one month or prepared according to the manufacturer's instructions.
5.8 Internal standard solution. ρ=250 mg/L
Fluorobenzene, chlorobenzene-d5 and 1,4-dichlorobenzene-d4 were selected as internal standards. A certified standard solution can be purchased directly.
5.9 Alternative standard solution. ρ=250 mg/L
Toluene-d8 and 4-bromofluorobenzene were used as substitutes. A certified standard solution can be purchased directly.
5.10 4-bromofluorobenzene (BFB) solution. ρ=25 mg/L
The certified standard solution can be purchased directly or can be prepared with a high concentration standard solution.
5.11 Quartz sand. 20~50 mesh. Before use, it is necessary to pass the test to confirm that the concentration of the target compound or target compound is lower than the method.
The detection limit.
5.12 Carrier gas. high purity helium, ≥99.999%, deoxidized by deoxidizer, dehydrated by molecular sieve.
Note 1. All the above standard solutions are treated with methanol as the solvent. The standard solution after preparation or unsealing should be placed in a compact bottle, and protected from light under 4 °C.
Save, the shelf life is generally 30d. Recover to room temperature and mix before use.
6 Instruments and equipment
6.1 Gas Chromatograph. Capillary split/splitless inlet for temperature programming.
6.2 Mass Spectrometer. 70eV Electron Impact (EI) Ionization Source with NIST Mass Spectrometry Library, Manual/Automatic Tuning, Data
Collection, quantitative analysis and library search functions.
6.3 Capillary column. 60 m × 0.25 mm; film thickness 1.4 μm (6 % nitrile propylphenyl, 94% dimethylpolysiloxane fixative),
Other equivalent capillary columns can also be used.
6.4 Headspace Sampler. with headspace bottle, gasket (PTFE/silicone or Teflon/butyl rubber), cap (snail)
Screw cap or gland used at one time).
6.5 Reciprocating Oscillator. The oscillation frequency is 150 times/min to fix the headspace bottle.
6.6 Ultrapure water preparation instrument or sub-boiling distiller.
6.7 Balance. Balance with an accuracy of 0.01g.
6.8 Microinjectors. 5 μl, 10 μl, 25 μl, 100 μl, 500 μl, 1000 μl.
6.9 Sampling equipment. shovel and stainless steel medicine spoon.
6.10 Portable refrigerator. 20L volume, temperature below 4 °C.
6.11 Brown compact bottle. 2 ml with Teflon liner and solid screw cap.
6.12 Sampling bottle. 60 ml threaded brown wide-mouth glass bottle with Teflon-silica liner screw cap.
6.13 Disposable Pasteur glass pipettes.
6.14 Common instruments and equipment used in general laboratories.
7 samples
7.1 Sample collection and preservation
7.1.1 Sample Collection
Soil samples were collected and stored in accordance with the relevant regulations of HJ/T 166. In accordance with the relevant provisions of GB 17378.3
Collection and storage of sediment samples. The tool for collecting samples should be applied to metal products and should be purified before use. Can be taken
Samples were screened at a high concentration and low concentration using a portable instrument for the determination of volatile organic compounds. All samples should be
Collect at least 3 parallel samples.
Use a shovel or a medicine spoon to collect the sample into the vial (6.12) as soon as possible and fill it as much as possible. Quickly remove sample vial
The sample adhered to the grain and the outer surface, and the sample bottle is sealed. Put it in a portable freezer and bring it back to the lab.
Note 2. When the concentration of volatile organic compounds in the sample is greater than 1000 μg/kg, the sample is regarded as a high content sample.
Note 3. Do not stir the soil and sediment during sample collection to avoid evaporation of organic matter in soil and sediment.
7.1.2 Sample storage
Samples should be analyzed as soon as they are sent to the laboratory. If it cannot be analyzed immediately, it should be sealed and stored below 4 °C, and the shelf life is not exceeded.
After 7 days. The sample storage area should be free of organic interference.
7.2 Preparation of samples
7.2.1 Low content sample
Remove the sample vial from the laboratory. After returning to room temperature, weigh 2g of the sample into the headspace bottle and quickly move it into the top empty bottle.
Add 10ml matrix modifier (5.5), 1.0μl substitute (5.9) and 2.0μl internal standard (5.8), immediately seal and oscillate
The oscillation on the device was oscillated at a frequency of 150 times/min for 10 min, to be tested.
7.2.2 High content sample
If the preliminary screening of volatile organic compounds at the site is high or low, the determination result is greater than 1000μg/kg.
High content sample. High-content samples were prepared as follows, and the vials for high-content sample testing were removed and allowed to return to room temperature.
Weigh 2g of sample into the headspace bottle, quickly add 10 ml of methanol (5.2), seal, and shake on the shaker at 150 times/min
The frequency oscillates for 10 min. After standing to settle, remove about 1 ml of extract with a disposable Pasteur glass pipette to 2 ml.
In a brown glass bottle, the extract can be centrifuged if necessary. The extract can be stored in a refrigerator at 4 ° C, guaranteed
The deposit period is 14 days.
After returning the extract to room temperature before analysis, add 2 g of quartz sand (5.11), 10 ml of matrix to an empty headspace vial.
Modifier (5.5) and 10 to 100 μl methanol extract. Add 2.0 μl of internal standard (5.8) and substitute (5.9) and seal immediately.
Oscillation on the oscillator was oscillated at a frequency of 150 times/min for 10 min, to be tested.
Note 4. If the concentration of the target compound in the methanol extract is high, it can be appropriately diluted by adding methanol.
Note 5. If the concentration value is too low or not detected by the high content method, the sample should be re-analyzed using the low content method.
7.3 Preparation of blank samples
7.3.1 Low content blank sample
Replace the sample with 2g quartz sand and prepare a low content blank sample according to the procedure of 7.2.1.
7.3.2 High content blank sample
Replace the high-content sample with 2g quartz sand (5.11) and prepare a high-content blank sample according to the procedure in 7.2.2.
7.4 Determination of moisture
The moisture content of the soil sample is determined according to HJ 613, and the moisture content of the sediment sample is determined according to GB 17378.5.
Row.
8 Analysis steps
8.1 Instrument Reference Conditions
Different working conditions of different models of headspace sampler, gas chromatograph and mass spectrometer should be different according to the instructions of the instrument.
The book is operated. The recommended reference conditions for this standard are as follows.
8.1.1 Headspace Sampler Reference Conditions
Heating equilibrium temperature 60~85 °C; heating equilibrium time 50 min; sampling needle temperature 100 ° C; transmission line temperature 110 ° C;
The transfer line is deactivated and has a quartz capillary column with an inner diameter of 0.32 mm; the pressure equalization time is 1 min; when injecting
0.2 min; needle setting time 0.4 min; headspace bottle pressure 23 psi.
8.1.2 Gas Chromatograph Reference Conditions
Temperature programmed. 40 ° C (for 2 min) 8 ° C/min 90 ° C (for 4 min) 6 ° C/min.200 ° C (guarantee
Hold 15 min).
Inlet temperature. 250 °C. Interface temperature. 230 °C. Carrier gas. helium; inlet pressure. 18 psi. Injection method.
Split injection, split ratio. 5.1.
8.1.3 Mass Spectrometer Reference Conditions
Scanning range. 35 amu~300 amu. Scan speed. 1 sec/scan. Ionization energy. 70 eV. Ion source temperature.
230 °C. Quadrupole temperature. 150 °C. Scan mode. full scan (SCAN) or selective ion (SIM) scan.
8.2 Calibration
8.2.1 Instrument performance check
The GC/MS system must perform an instrument performance check before daily analysis. Pipette 2μl of BFB solution (5.10)
Direct injection through the GC inlet and analysis by GC/MS. The critical ion abundance of BFB obtained by GC/MS system should be
Meet the criteria specified in Table 1, otherwise some parameters of the mass spectrometer need to be adjusted or the ion source cleaned.
Table 1 4-bromofluorobenzene ion abundance standard
Mass-to-charge ratio ion abundance standard mass-to-charge ratio abundance standard
95 base peak, 100% relative abundance 175 mass 174 5% to 9%
96% 95% 5% to 9% 176 Quality 95% to 105% 174
173 is less than 25% of mass 174 177 is 5% to 10% of mass 176
174 is greater than 50% of mass 95
8.2.2 Drawing of the calibration curve
Add 2 g of quartz sand (5.11), 10 ml of matrix modifier (5.5) to the 5 top empty bottles, and then divide into each bottle.
Do not add a certain amount of standard use solution (5.7), the target compound concentration is 5, 10, 20, 50, 100μg/L;
Add a certain amount of substitute (5.9) to each headspace bottle, and add 2.0μl of internal standard solution (5.8), immediately
seal. The concentration of the calibration series is shown in Table 2. The configured standard series sample is oscillated on the oscillator at a frequency of 150 times/min
Oscillate for 10 min, analyze the samples from low to high concentrations, draw a calibration curve or calculate the average response factor. In this standard
The standard total ion chromatogram of 36 volatile organic compounds was determined by standard conditions, as shown in Figure 1.
Table 2 Calibration Series Concentration
Calibration series concentration (μg/L) Substitute concentration (μg/L) Internal standard concentration (μg/L)
1-chloroethylene; 2-1,1-dichloroethylene; 3-dichloromethane; 4-trans-1,2-dichloroethylene; 5-1,2-dichloroethane; 6-cis-1, 2-dichloroethylene; 7-
Chloroform; 8-1,1,1-trichloroethane; 9-carbon tetrachloride; 10-1,2-dichloroethanebenzene; 11-fluorobenzene (internal standard 1); 12-trichloroethylene; 13-1,2-
Dichloropropane; 14-bromodichloromethane; 15-toluene-d8 (alternative 1); 16-toluene; 17-1,1,2-trichloroethane; 18-tetrachloroethylene; 19-two
Bromochloromethane; 20-1,2-dibromoethane; 21-chlorobenzene-d5 (internal standard 2); 22-chlorobenzene; 23-1,1,1,2-tetrachloroethane; 24- Ethylbenzene; 25-room-
Xylene p-xylene; 26-o-xylene styrene; 27-bromoform; 28-4-bromofluorobenzene (substitute 2); 29-1,1,2,2-tetrachloroethane;
30-1,2,3-trichloropropane; 31-1,3,5-trimethylbenzene; 32-1,2,4-trimethylbenzene;
33-1,3-dichlorobenzene; 34-1,4-dichlorobenzene-d4 (internal standard 3); 35-1,4-dichlorobenzene; 36-1,2-dichlorobenzene; 37-1 , 2,4-trichlorobenzene; 38-six
Chloroprene.
Figure 1 36 kinds of volatile organic compounds standard total ion flow diagram
8.2.2.1 Establishing a calibration curve with an average relative response factor
The relative response factor (RRFi) of the target (or surrogate) in point i of the standard series, calculated according to formula (1)
Count.
ISi
ISi
i A
ARRF ρ
ρ×= (1)
In the formula.
The relative response factor of the i-th target (or surrogate) in the RRFi-standard series;
The response value of the quantified ion of the i-th target (or substitute) in the Ai-standard series;
The i-th point in the AISi-standard series corresponds to the target (or substitute) corresponding to the internal standard quantitation ion response value;
The concentration of the internal standard in the ρIS-standard series, 50 μg/L;
The mass concentration of the i-th target (or substitute) in the ρi-standard series, μg/L.
The average relative response factor RRF of the target (or substitute) is calculated according to formula (2).
RRF
RRF
I∑
== 1 (2)
In the formula.
RRF - the average relative response factor of the target (or substitute);
RRFi--the relative response factor of the i-th target (or substitute) in the standard series;
n--Standard series points, 5.
The standard deviation of RRF is calculated according to formula (3).
)( 2
RRFRRF
SD
(3)
The relative standard deviation of RRF is calculated according to formula (4).
0×=
RRF
SDRSD (4)
The relative standard deviation (RSD) of the relative response factor (RRF) of the standard series of targets (or substitutes) should be less than
At 20%.
8.2.2.2 Drawing a calibration curve using least squares
The ratio of the response of the target compound to the corresponding internal standard is plotted on the ordinate, and the concentration ratio is plotted on the abscissa, which is established by least squares method.
Calibration curve. If the correlation coefficient of the established linear calibration curve is less than 0.990, a nonlinear fitting curve can also be used.
For line calibration, the curve correlation coefficient needs to be greater than or equal to 0.990. When using a non-linear calibration curve, at least 6 concentration points should be used
Perform calibration.
8.3 Determination
The prepared sample (7.2) was placed on a headspace sampler and measured according to the instrument reference conditions (8.1).
8.4 Blank test
The prepared blank sample (7.3) was placed on a headspace sampler and measured according to the instrument reference conditions (8.1).
9 Calculation and representation of results
9.1 Qualitative analysis of target compounds
The target is characterized by relative retention time (or retention time) and by comparison to a standard material mass spectrum.
9.2 Quantitative analysis of targets
The calculation is based on the response value of the first characteristic ion of the target and the internal standard. When the first characteristic ion of the target in the sample has
For interference, the second characteristic ion quantification can be used, see Appendix B for details.
9.2.1 Calculation of the mass concentration ρex of the target (or substitute) in the sample
9.2.1.1 Calculated using the average relative response factor
When the target (or substitute) is calibrated using the average relative response factor, the mass concentration of the target in the sample is ρex
Calculate according to formula (5).
RRFA
IS
ISx
Ex ×
×= ρρ (5)
In the formula.
Ρex - the mass concentration of the target (or substitute) in the sample, μg/L;
Ax -- the target (or substitute) quantified ion response value;
AIS - the response value of the internal standard quantitative ion corresponding to the target (or substitute);
ρIS - concentration of internal standard, μg/L;
RRF - The average relative response factor of the target (or surrogate).
9.2.1.2 Calculation with linear or nonlinear calibration curves
When the target is calibrated using a linear or non-linear calibration curve, the target mass concentration ρex in the sample passes the corresponding
The calibration curve is calculated.
9.2.2 The content of volatile organic compounds (μg/kg) in low-content samples is calculated according to formula (6).
) 100 (
Wm
Ex
−×
××= ρω (6)
In the formula.
Ω-content of the target compound in the sample, μg/kg;
Exρ - calculate the concentration of the target compound (or substitute) based on the response factor or calibration curve, μg/L;
10-base modifier volume, ml;
W-water content of the sample, %;
M-sample amount (wet weight), g.
9.2.3 The content of volatile organic compounds (μg/kg) in high-content samples is calculated according to formula (7).
Cex
Vwm
KV
×−×
××××=
) 100 (
Ωω (7)
In the formula.
ω - the content of the target compound in the sample, μg/kg;
Exρ -- calculate the concentration of the target compound based on the response factor or calibration curve, μg/L;
10 - matrix modifier volume, ml;
Vc - extract volume, ml;
m -- sample amount (wet weight), g;
Vs - volume of methanol extract used for headspace determination, ml;
w -- the moisture content of the sample, %;
K - dilution ratio of the extract.
Note 6. If the sample moisture content is greater than 10%, the extract volume Vc should be the sum of the volume of methanol and water in the sample; if the sample moisture content is less than
Equal to 10% and Vc is 10 ml.
9.3 Result representation
9.3.1 When the measurement result is less than 100 μg/kg, one digit after the decimal point is retained; when the measurement result is greater than or equal to 100 μg/kg
Keep 3 significant digits.
9.3.2 When using the capillary column specified in this standard, the two peaks of meta-xylene and para-xylene are inseparable, and their content is
The sum of the two.
10 Precision and accuracy
10.1 Precision
Six laboratories measured the uniform samples of soil and sediment at two different levels.
When the concentration of volatile organic compounds in the soil is about 100μg/kg and.200μg/kg, the relative standard deviation range in the laboratory is divided.
Not 1.1% to 13% and 1.4% to 15%; the relative standard deviation between laboratories is 1.8% to 14% and 6.7%, respectively.
17%; the repeatability limits ranged from 8.8 to 19.4 μg/kg and 32.5 to 116 μg/kg, respectively; the reproducibility limits rang...
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