HJ 736-2015Soil and sediment. Determination of volatile halohydrocarbons. Headspace gas chromatography mass spectrometry (English PDF)

Foreword

For the implementation of the "People's Republic of China Environmental Protection Law" to protect the environment, protect human health, regulate soil and sediment Determination of volatile halogenated hydrocarbons, the development of this standard.

This standard specifies the headspace/gas chromatography-mass spectrometry for the determination of 35 volatile halogenated hydrocarbons such as methyl chloride in soil and sediments.

This standard is the first release.

Appendix A to this standard is a normative appendix, Appendix B and Appendix C are informative appendices.

This standard is organized by the Ministry of Environmental Protection Science and Technology Standards Division.

The main drafting unit of this standard. Harbin Environmental Monitoring Center Station.

The standard verification unit. Heilongjiang Province Environmental Monitoring Center Station, Dalian Environmental Monitoring Center, Changchun City Environmental Monitoring Heart station, Anshan City Environmental Monitoring Center Station, Qiqihar City Environmental Monitoring Center Station and Daqing City Environmental Monitoring Center Station.

This standard is approved by the Ministry of Environmental Protection on February 7, 2015.

This standard is implemented as of April 1, 2015.

This standard is explained by the Ministry of Environmental Protection.

Determination of volatile halohydrocarbons in soil and sediments Headspace/gas chromatography - mass spectrometry WARNING. The internal standard, substitute and standard solution used in the test are volatile, and the solution should be prepared.

Fume hood to operate; should be required to wear protective equipment, to avoid contact with skin and clothing.

1 Scope of application

This standard specifies headspace/gas chromatography-mass spectrometry for the determination of volatile halogenated hydrocarbons in soil and sediments.

This standard is applicable to the determination of 35 kinds of volatile halogenated hydrocarbons such as methyl chloride in soil and sediments. Other volatile halogenated hydrocarbons If verification is also applicable to this standard.

When the sampling amount of 2g, 35 kinds of volatile halogenated hydrocarbons detection limit of 2 ~ 3 µg/kg, the determination of the lower limit of 8 ~ 12 µg/kg. See Appendix A. for details.

2 Normative reference documents

The contents of this standard refer to the following documents or their terms. Those who do not specify the date of the reference file, the effective version of the appropriate for this standard.

GB 17378.3 Marine Monitoring Specification Part 3 Sample Collection Storage and Transportation GB 17378.5 Marine monitoring regulations Part 5 Sediment analysis Determination of Dry Matter and Moisture in Soil Technical specification for soil environmental monitoring

3 Principle of the method

Under certain temperature conditions, the volatile halogenated hydrocarbons in the sample of the headspace bottle evaporate to the liquid space, resulting in a certain amount of steam Pressure, and to achieve gas-liquid three-phase equilibrium, take the gas sample into the gas chromatographic separation, with a mass spectrometer for testing. according to Retention time, fragment ion mass ratio and different ion abundance ratio qualitative, internal standard method quantitative.

4 Reagents and materials

4.1 Experimental water. secondary distilled water or pure water equipment to prepare water, before use to go through blank test to confirm that no target compounds or the target compound concentration is below the method detection limit.

4.2 methanol (CH3OH). pesticide residues, before use to be tested to confirm that no target or target concentration is lower than the method of inspection Limit.

4.3 sodium chloride (NaCl). excellent grade, in the muffle furnace at 400 °C baking 4h, placed in a dryer to cool to room temperature, Stored in a brown glass bottle.

4.4 phosphoric acid (H3PO4). excellent grade pure.

4.5 Substrate modifier. Phosphoric acid (4.4) was added dropwise to 100 ml of experimental water to adjust the pH of the solution to less than 2;

36 g of sodium chloride (4.3). Stored at 4 °C, can be stored for 6 months.

24.6 standard stock solution. rho =.2000mg/L.

Direct purchase of commercially available standard solution. Store at or below -10 ° C, or refer to the manufacturer's product description. use should be restored to room temperature, and shake. Kaifeng in a dense bottle can be kept for a month.

4.7 standard use of liquid. rho = 20mg/L.

Take appropriate standard stock solution (4.6) and dilute with methanol (4.2). In the dense bottle -10 °C below the light protection Save, save for a week.

4.8 internal standard stock solution. rho =.2000mg/L.

Fluorobenzene, 1-chloro-2-bromopropane, 4-bromofluorobenzene as internal standard. Can be purchased directly to prove the standard solution can also be used standard Material preparation. Store in light below -10 ° C or refer to the manufacturer's product description. Use should be restored to room temperature, and shake.

Kaifeng in a dense bottle can be kept for a month.

4.9 internal standard use of liquid. rho = 25mg/L.

Take appropriate internal standard stock solution (4.8) and dilute with methanol (4.2). In the dense bottle -10 °C below the light protection Save, save for a week.

4.10 Alternative stock solution. rho =.2000mg/L.

Use dichloromethane-d2,1,2-dichlorobenzene-d4 as a substitute. Can be purchased directly to prove the standard solution can also be used standard Material preparation. Store in light below -10 ° C or refer to the manufacturer's product description. Use should be restored to room temperature, and shake.

Kaifeng in a dense bottle can be kept for a month.

4.11 Substitute liquid. rho = 25 mg/L.

Take appropriate stock solution (4.10) and dilute it with methanol (4.2). In the dense bottle -10 °C below the dark Save, save for one week.

4.12 4-bromofluorobenzene (BFB) solution. rho = 25 mg/L.

Can be directly purchased certified standard solution can also be prepared with standard materials. Store at or below -10 ° C or refer to the manufacturer of the product description. Use should be restored to room temperature, and shake. Kaifeng in a dense bottle can be kept for a month.

4.13 quartz sand. 20 to 50 mesh, before use to be tested to confirm that no target compound or target compound concentration below Legal limit.

4.14 helium. purity >= 99.999%, deoxidized by deoxidizer, molecular sieve dehydration.

5 Instruments and equipment

5.1 Sampling equipment. shovel and stainless steel spoon.

5.2 Sampling Bottle. 60ml threaded brown glass bottle with polytetrafluoroethylene liner.

5.3 Gas Chromatography-Mass Spectrometer. EI Ionization Source.

5.4 Column. quartz capillary column, length 30 m, diameter 0.25 mm, film thickness 1.4 µm, stationary phase 6% nitrile / 94% dimethylpolysiloxane, and other equivalent capillary columns may also be used.

5.5 headspace autosampler. a headspace bottle.

5.6 Headspace Bottle. 22ml, top empty bottle with PTFE cover (with headspace sampler), cap (screw Capping or one-time gland).

5.7 microinjector. 10 µl, 25 µl, 100 µl, 250 µl, 500 µl and 1000 µl.

5.8 balance. accuracy of 0.01g.

35.9 reciprocating oscillator. shock frequency 150 times/min, can be fixed head empty bottle.

5.10 brown dense bottle. 2ml, with PTFE packing.

5.11 pH meter. accuracy of ± 0.05.

5.12 portable refrigerated containers. volume 20L. The temperature below 4 °C.

5.13 General laboratory equipment and equipment commonly used.

6 Samples

47 Analysis steps

7.1 Instrument reference conditions

7.1.1 Headspace device reference conditions Equilibrium time. 30min; equilibrium temperature. 60 °C; injection time. 0.04min; transmission line temperature. 110 °C.

7.1.2 Gas chromatograph reference conditions Program temperature. 35 °C (5 min) 5 °C/min 180 °C 20 °C/min.200 °C (5 min); inlet temperature 20. 1; carrier gas. helium; interface temperature. 230 ° C; column flow rate.

1.2 ml/min.

7.1.3 Mass spectrometer reference conditions Ionization mode. EI; ion source temperature..200 ° C; transmission line temperature. 230 ° C; electron accelerating voltage. 70 eV;

Detection method. Full Scan method; Quality range. 35 amu ~ 300amu.

7.2 Calibration

7.2.1 Instrument performance check the performance of the gas chromatograph - mass spectrometer should be checked before analyzing the sample daily. Take 4-bromofluorobenzene (BFB) (4.12) Liquid 1 µl direct into the gas chromatographic analysis, the resulting BFB spectrum should meet the requirements specified in Table 1 or refer to the manufacturer's Description.

Table 1 BFB critical ion abundance standard

Mass ratio (m/z) ion abundance standard mass ratio (m/z) ion abundance standard 50% of the base of 15% to 40% 174 is greater than 50% of the base peak 75% of the base peak of 60% to 60% 175 174 peak of 5% to 9% 95 base, 100% relative abundance 176 174 peak 95% to 101% 96% of the base peak of 5% to 9% 177 176 peak of 5% to 9%

173 Less than 174 peaks 2% - -

7.2.2 Drawing of calibration curves to the five top empty bottles were added 2 g of quartz sand (4.13), 10.0 ml of the matrix modifier (4.5), respectively, (4.1) Preparation of target and substitute contents of 20, 40, 100,.200, 400ng of the standard series, and were added 4.0µl internal standard with the liquid (4.9), immediately sealed, fully shaken for 10min, Analyze according to the instrument reference condition (7.1) to obtain the chromatogram of the different target. Quantify the response of the target ion the ratio of the value to the response value of the internal standard substance is the ordinate, the target content (ng) is the abscissa, and the calibration curve is drawn.

Figure 1 shows the chromatogram of the target under the instrument conditions specified in this standard.

5-chloroethane; 6-trichlorofluoromethane; 7-1, 1-dichloroethylene; 3-chloropentane;

8-dichloroethane-d2 (substitute 1); 9-dichloromethane; 10-trans-1,2-dichloroethylene; 11-1,1-dichloroethane; Propane 13-carbonyl chloride; 18-1, 1-dichloroethane; 14-bromochloromethane; 15-chloroform; 16-1,1,1-trichloroethane; Propylene;

19-1,2-dichloroethane; 20-fluorobenzene (internal standard 1); 21-trichlorethylene; 22-1,2-dichloropropane; 23-dibromomethane;

Chloroethane; 25-cis-1,3-dichloropropene; 26-trans-1,3-dichloropropene; 27-1-chloro-2-bromopropane (internal standard 2); 28-1,1,2 - trichloroethane;

29-tetrachlorethylene; 30-1,3-dichloropropane; 31-dibromochloromethane; 32-1,2-dibromoethane; 33-1,1,1,2-tetrachloroethane; 34-bromine (Internal standard 3); 36-1,1,2,2-tetrachloroethane; 37-1,2,3-trichloropropane; 38-o-dichlorobenzene-d4 (Alternative 2);

39-1,2-dibromo-3-chloropropane; 40-hexachlorobutadiene.

Figure 1 The chromatogram of the target

7.2.2.1 Establish the calibration curve with the average response factor the relative response factor (iRRF) of the standard series i (target) (or substitutes) is calculated according to equation (1).

Where iRRF - the relative response factor for the i-th target (or substitute) in the standard series;

IA - the response value of the quantified ions of the i-th target (or substitute) in the standard series;

ISiA - the response value of the corresponding target ion in the standard series of the i-th target (or substitute) ISi - the content of the internal standard in the standard series, ng;

I__ - the content of the i-point target (or substitute) in the standard series ng.

The average relative response of the target (or substitute) is calculated according to equation (2).

Where. RRF - the average relative response factor for the target (or substitute);

IRRF - the relative response of the i-point target (or substitute) in the standard series;

N - standard series points.

RRF

RRF

ISi

ISi

ARRF

The standard deviation of 6RRF is calculated according to equation (3).

The relative standard deviation of RRF is calculated according to equation (4).

The relative standard deviation (RSD) of the standard series of target (or substitutes) relative response factor (RRF) should be less than at 20%.

7.2.2.2 Draw the calibration curve with the least squares method the response ratio of the target compound and the corresponding internal standard is the ordinate, the concentration ratio is the abscissa, and the least squares method is used Calibration curve, the correlation coefficient of the standard curve >= 0.990. If the correlation coefficient of the calibration curve is less than 0.990, it can also be used the linear fitting curve is calibrated, but should be calibrated using at least six concentration points.

7.3 Sample determination the prepared sample (6.3) was measured according to the instrument reference conditions (7.1).

7.4 blank test

The prepared sample (6.4) was measured according to the instrument reference conditions (7.1).

Calculation and representation of results

8.1 Qualitative analysis Data were collected in full scan, with the relative retention time (RRT) of the target compound in the sample, the auxiliary qualitative ion and the target ion abundance ratio (Q) is qualitatively variable in the standard solution. The relative retention time of the target compound in the sample the difference in the relative retention time of the compound with the calibration curve should be within ± 0.06. Auxiliary qualitative separation of the target compound in the sample (Q-sample) and the standard curve of the target compound of the auxiliary qualitative ion and quantitative ion peak area ratio (Q standard) relative deviation control within ± 30%.

Calculate the relative retention time RRT according to equation (5) ISRT RTRRT x = (5) where. RRT - relative retention time;

RTX - retention time of target, min;

RTIS - retention time of the internal standard, min.

Mean relative retention time (RRT). Relative retention time average of the same target compound in the standard series According to the formula (6) to calculate the auxiliary qualitative ion and quantitative ion peak area ratio (Q) ( ) RRFRRF SD 0 x distance RRF SDRSD 7t AQ = (6) where. At - quantitative ion peak area;

Aq - auxiliary qualitative ion peak area.

8.2 Quantitative analysis Calculated according to the response value of the target and internal standard quantitation ions. When the quantitation ions of the target in the sample interfere with, Auxiliary ion quantification can be used, as detailed in Appendix B.

8.2.1 Calculation of target mass (or substitute) mass 1m

8.2.1.1 Calculate with the average relative response factor when the target (or substitute) is calibrated using the average relative response factor, the content of the target is 1 m according to equation (7) Calculation.

Where. 1m - the content of the target (or substitute), ng;

XA - the response value of the target ion (or substitute) quantitative ion;

ISm - content of internal standard substance, ng;

ISA - the response value of the internal standard quantitative ion corresponding to the target (or substitute);

RRF - the average relative response factor for the target (or substitute).

8.2.1.2 Calculate with a linear or non-linear calibration curve when the target is calibrated with a linear or non-linear calibration curve, the target content is 1 m through the corresponding calibration Line calculation.

8.2.2 Calculation of soil sample results the concentration of the target in the low content sample (µg/kg) is calculated according to the formula (8).

DmWm

Where. - concentration of the target in the sample, µg/kg;

1m - the content of the target (or substitute) found on the calibration curve, ng;

M - sample volume (wet weight), g;

DmW - sample dry matter content,%.

The concentration of the target in the high content sample (µg/kg) is calculated according to the formula (9).

Dms

WmV

FVm

xx= 1 (9)

Where. - concentration of the target in the sample, µg/kg;

RRFA

MAm

ISx

81m - the content of the target (or substitute) found on the calibration curve, ng;

CV - volume of extract, ml;

M - sample volume (wet weight), g;

SV - volume of extract for headspace, ml;

DmW - sample dry matter content,%;

F - the dilution factor of the extract.

8.2.3 Calculation of sediment sample results the concentration of the target in the low content sample (µg/kg) is calculated according to the formula (10).

1 (10)

Where. - concentration of the target in the sample, µg/kg;

1m - the content of the target (or substitute) found on the calibration curve, ng;

M - the amount of sample (wet weight), g.

W - sample moisture content,%.

The concentration of the target in the high content sample (µg/kg) is calculated according to equation (11).

) (WmV

FVm

xx= (11)

Where. - concentration of the target in the sample, µg/kg;

1m - the content of the target (or substitute) found on the calibration curve, ng;

CV - volume of extract, ml;

M - sample volume (wet weight), g;

SV - volume of extract for headspace, ml;

W - sample moisture content,%;

F - the dilution factor of the extract.

8.3 results show

When the result is less than 100 g/kg, one decimal place is retained; when the result is greater than or equal to 100 g/kg, Reserved 3 significant digits.

9 precision and accuracy 9.1 precision Six laboratories were tested by headspace/gas chromatography-mass spectrometry at 10 µg/kg, 50 µg/kg and.200 µg/kg, respectively the relative standard deviations in the laboratory were 1.6% ~ 12%, 1.7% ~ 15%, 0.5% ~ 9.7%, respectively.

The relative standard deviations were. 4.0% ~ 10%, 6.3% ~ 13%, 3.9% ~ 12%, the repeatability limits were 1.5 ~ 2.4µg/kg, 5.8 ~ 10.4µg/kg, 20.9 ~ 31.7µg/kg, the reproducibility limits were 2.1 ~ 3.1µg/kg, 11.4 ~ 19.5µg/kg, 32.1 ~ 64.2 µg/kg.

9.2 Accuracy

The actual samples of soil and ...