HJ 890-2017Soil and sediment. Determination of polychlorinated biphenyl mixtures. Gas chromatography (English PDF)

Foreword

In order to carry out "Environmental Protection Law of the People's Republic of China", protect the environment, protect human health, regulate soil and sediment Determination of PCBs in industrial mixtures, the development of this standard.

This standard specifies the determination of soil and sediment in the PCB by gas chromatography.

This standard Appendix A, Appendix B and Appendix C are informative appendix.

This standard is released for the first time.

This standard by the Environmental Protection Department of Environmental Monitoring Division and Science and Technology Standards Division to develop.

This standard was drafted. National Environmental Analysis Test Center.

This standard verification unit. Hunan Provincial Environmental Monitoring Center, Xiangtan City Environmental Monitoring Station, Wuxi City Environmental Monitoring Center, the Soviet Union State Environmental Monitoring Center, Shandong Provincial Analysis and Testing Center and Beijing Jinxiu earth technology testing and analysis center.

This standard MEP approved on December 17, 2017.

This standard since February 1, 2018 implementation.

This standard is interpreted by the MEP.

1 Soil and sediment polychlorinated biphenyls Determination of gas chromatography

Warning. The organic solvents and reagents used in this method have some toxicity. The experimental operation should be carried out in a fume hood and press Provisions on wearing protective equipment, to avoid contact with skin and clothing.

1 scope of application this standard specifies the determination of soil and sediment in the PCB by gas chromatography.

This standard applies to soil and sediment PCB1221, PCB1242, PCB1248, PCB1254 and PCB1260 A total of 5 kinds of PCBs determination of industrial products, other PCBs industrial products through the verification can also be measured using this method.

When the sample volume is 5 g and the volume of constant volume is 1.0 ml, the detection limits of the 5 PCBs industrial products by this method are 5 µg/kg, the lower limit of determination of 20 µg/kg.

2 Normative references

This standard references the following documents or the terms. For undated references, the effective version applies to this book standard.

GB 17378.3 Marine monitoring code - Part 3. Sample collection, storage and transport GB 17378.5 Marine monitoring code - Part 5. Sediment analysis HJ 494 water sampling technical guidance HJ 613 Determination of soil dry matter and moisture Gravimetric method HJ 783 Extraction of organic matter from soils and sediments by pressurized fluid extraction HJ/T 166 Soil Environmental Monitoring Technical Specifications

3 Terms and definitions

The following terms and definitions apply to this standard.

PCBs congeners

Polychlorinated biphenyls (PCBs), also known as chlorinated biphenyl, ring is a hydrogen atom is replaced by a class of chlorine atoms formed Synthetic organic compounds, from a chlorinated biphenyl to 10 chlorinated biphenyl, a total of 209 kinds of compounds, although the molecular formula of these compounds are different, but there is a similar chemical structure, known as homologues.

Feature recognition peak diagnostic peak each polychlorinated biphenyl industrial product has between 70 and 80 identifiable peaks in the GC/ECD spectrum. Some of these chromatograms Peak abundance larger, better separation, and the relative position and intensity of the surrounding peaks have obvious characteristics, easy to identify, known as special Sign recognition peak.

24 Method principle

PCBs in soils and sediment samples were extracted with organic solvents and the extract was concentrated with concentrated sulfuric acid and purified on a silica gel column.

After volume determination by gas chromatography, electron capture detector detection. Retention time and peak shape of the sample peak passed the standard Qualitative comparison of products, select 5 to 10 characteristics of identification peaks, with external standard quantitative.

5 Interference and elimination Soil and sediments may exist in the BHC, organophosphorus pesticides, oxygenated compounds will not interfere with the determination of PCBs.

DDE, DDD and DDE at concentrations greater than 5 µg/kg interfere with quantification and should be avoided in the selection of characterization peaks the peak time of the thing.

6 Reagents and materials Unless otherwise stated, analytical grade reagents that meet national standards are used.

6.1 Experimental water in a 1 L separatory funnel by adding 500 ml of deionized or distilled water and 100 ml of n-hexane, shaking 10 min standing After the layer, the aqueous phase is released and stored in brown glass bottles for later use. Hexane can be reused 3 times.

6.2 n-Hexane (C6H14). pesticide residues, or PCBs were not detected after 100-fold concentration.

6.3 Dichloromethane (C2H2Cl2). pesticide grade, or 50 times concentrated PCBs were not detected.

6.4 acetone (C3H6O). pesticide residues, or PCBs were not detected.

6.5 Absolute ethanol (C2H5OH). HPLC grade, PCBs were not detected after 100 times concentration.

6.6 Nitric acid. rho (HNO3) = 1.42 g/ml.

6.7 Sulfuric acid. rho (H2SO4) = 1.84 g/ml.

6.8 Potassium hydroxide (KOH). Purity 85%.

6.9 Sodium bicarbonate (NaHCO3).

6.10 Anhydrous sodium sulfate (Na2SO4).

Muffle furnace 450 °C burning 4 h, remove and put in a clean dryer standby.

6.11 Dichloromethane - n-hexane mixed solution. 1 1.

Mix with methylene chloride (6.3) and n-hexane (6.2) at a volume ratio of 1. 1.

6.12 nitric acid solution. rho (HNO3) = 1 mol/L.

Take 6.9 ml of nitric acid (6.6), add 100 ml of water and mix well.

6.13 sulfuric acid solution. 1 9.

Take 10 ml of sulfuric acid (6.7), add 90 ml of water and mix.

6.14 Potassium hydroxide solution. rho (KOH) = 0.05 g/ml.

Take 59 g potassium hydroxide (6.8) dissolved in a small amount of water, diluted to 1 L.

6.15 Potassium hydroxide - ethanol solution. 1 mol/L.

Weigh 33 g of potassium hydroxide (6.8) added to 500 ml of anhydrous ethanol (6.5), dissolved and mixed.

6.16 Sodium bicarbonate solution. rho (NaHCO3) = 0.02 g/ml.

3 Weigh 2 g of sodium bicarbonate (6.9), dissolve in 100 ml of water and mix well.

6.17 PCB standards

PCB1221, PCB1242, PCB1248, PCB1254, PCB1260 and other commercial PCB standards.

Note. Some of the commercially available PCB series of standard samples of methanol solvent, methanol and n-hexane, petroleum ether and other non-polar solvents can not be any ratio Dilution ratio should be greater than 15. 1.

6.18 PCB stock standard solution. rho = 5.00 mg/L.

Dilute PCB standards with n-hexane (6.2) (6.17). Dark sealed in a standard sample bottle cold, at least Save for 6 months.

6.19 copper wire (beads or powder).

Before use soaked in nitric acid solution (6.12) to remove the surface oxide layer, washed with water until neutral and then with acetone (6.4) and n-hexane (6.2) three times.

6.20 Silica. 75 µm ~ 150 µm (200 mesh ~ 100 mesh).

130 °C activated 16 h, placed in a clean dryer standby.

6.21 alkaline silica gel.

Take silica gel (6.20) 98 g, add potassium hydroxide solution (6.14) 40 ml, shake well, into a powder, after bottling Store in the dryer.

6.22 acidic silica gel.

Take silica gel (6.20) 56 g, add sulfuric acid (6.7) 44 g, shake well, into a powder, stored in a dry bottle in the device.

6.23 Compound Silica Column. The following methods can be used to fill, you can also buy commercially available products.

Place a small glass wool (6.27) on the bottom of the column (7.6), add 40 ml of n-hexane (6.2) and fill in with water 1 g of sodium sulfate (6.10), 1 g of silica gel (6.20), 3 g of basic silica gel (6.21), 1 g of silica gel (6.20) 8 g, silica gel (6.20) 1 g, anhydrous sodium sulfate (6.10) 1 g. Release n-hexane to make it just above the silica gel column Anhydrous sodium flush, stand-by.

6.24 Silica gel column. Commercial column, 1000 mg/6 ml, polyethylene or polypropylene column.

6.25 Diatomaceous earth. 75 µm to 150 µm (200 mesh to 100 mesh).

Muffle furnace 450 °C burning 4 h, remove and put in a clean dryer standby.

6.26 quartz sand. 150 µm ~ 830 µm (100 mesh ~ 20 mesh).

Muffle furnace 450 °C burning 4 h, remove and put in a clean dryer standby.

6.27 clean glass wool.

6.28 high purity nitrogen. purity >= 99.999%.

7 instruments and equipment

7.1 Gas Chromatograph. with split/splitless inlet, temperature programmed function, and electron capture detector.

7.2 Column. Quartz capillary column.

Analytical column. non-polar, 30 mx 0.25 mm x 0.25 µm, 100% polymethylsiloxane fixative, or other equivalent chromatographic column;

Confirm column. medium polarity, 30 mx 0.25 mm x 0.25 µm, 14% cyanopropylphenyl-86% dimethylpolysiloxane fixative, 4 or other equivalent column.

7.3 Extraction device. Soxhlet extraction device, automatic Soxhlet extractor, accelerated solvent extractor or other equivalent extraction Device.

7.4 Concentration device. nitrogen blowing concentrator, rotary evaporator, KD concentrator, parallel centrifugal evaporator or other performance equivalent device of.

7.5 glass reflow device.

7.6 Column. 300 mm long, 10 mm ~ 15 mm ID, glass column with Teflon piston on the bottom.

7.7 Analytical Balance. Feel 0.01 g.

7.8 General laboratory commonly used instruments and equipment.

8 samples

8.1 Sample Collection and Storage Soil samples were collected and stored according to the relevant requirements of HJ/T 166 and water bodies were collected according to the relevant requirements of HJ 494 Samples of the material, in accordance with the relevant requirements of GB 17378.3 collected marine sediment samples. After the sample is collected, it is protected from light at 4 ° C Storage, within 30 d to complete the extraction, within 40 d to complete the analysis of the extract.

8.2 Preparation of samples Remove the foreign material from the sample and weigh 5 g (accurate to 0.01 g) into the round bottom flask. When using Soxhlet extraction, the sample was added an appropriate amount of anhydrous sodium sulfate (6.10), ground into a sand-like, into the extraction tube. For the higher sulfur deposition Add sample amount of copper powder (6.19). When using pressurized fluid extraction, add appropriate amount of diatomaceous earth (6.25) to the sample and mill to block-free, into the extraction cell. For high sulfur sediment samples add appropriate amount of copper powder (6.19).

Preparation of air-dried soil and sediment samples, respectively, according to HJ/T 166 and GB 17378.3 related parts to operate.

8.3 Determination of moisture Weigh the sample at the same time, according to HJ 613 determination of soil samples dry matter content, measured in accordance with GB 17378.5 sediment Sample moisture content.

8.4 Preparation of test specimens

8.4.1 Extraction

8.4.1.1 Lye reflux

In a round bottom flask containing the sample, add potassium hydroxide - ethanol solution (6.15) 50 ml, boiling water bath reflux 1 h, will the supernatant was transferred to a separatory funnel pre-filled with 100 ml of n-hexane (6.2) and 500 ml of water and the alkaline residue was eluted with 20 ml Ethanol (6.5) was washed three times and combined into a separatory funnel. After adjusting the solution to neutral with sulfuric acid solution (6.13), extract for 5 min ~ 10 min, stand still stratified, discard the water sample.

8.4.1.2 Pressurized fluid extraction Put the extraction tank and the receiving bottle correspondingly, extractant is dichloromethane-n-hexane mixed solution (6.11), extraction temperature 5100 °C, heating time 5 min, extraction time 5 min, extraction cycle 2 times, extraction nitrogen purge 60 s. Or according to HJ 783 Set and optimize extraction conditions.

8.4.1.3 Soxhlet extraction and automatic Soxhlet extraction the cartridge into the Soxhlet extraction tube, connect the extraction device, turn on the heater, control the speed, dichloromethane -the mixed solution of alkanes (6.11) was refluxed for 16 h. Or in accordance with the extraction conditions optimized for Soxhlet extraction 4 h ~ 6 h.

8.4.2 Purification

8.4.2.1 sulfuric acid purification the extraction solvent conversion solvent for n-hexane, add about 5 ml ~ 10 ml of sulfuric acid (6.7), shake for a moment after standing layered, abandoned the sulfuric acid phase is removed and the sulfuric acid wash is repeated until the sulfuric acid phase is colorless. Add 100 ml sodium bicarbonate solution (6.16), shake 2 min, Stand stratification, discard the water phase and repeat until the water sample pH is neutral. In a glass funnel, first load a small amount of glass Wool (6.27), then about 10 g of anhydrous sodium sulfate (6.10) and 15 ml of n-hexane (6.2), discard detergent. The extract was added and collected in a pear-shaped flask. Concentrate to about 2 ml with suitable concentration equipment, transfer to scale test Tube.

8.4.2.2 silica gel column purification in column (7.6), install a small amount of glass wool (6.27) first. Add 20 ml of n-hexane (6.2) beforehand Add 3.0 g of silica gel (6.20) to the cup, stir, pour into the column and wash the beaker with a small amount of n-hexane (6.2) Into the column, emit excess n-hexane 0.5 cm above the silica gel layer, add a small amount of anhydrous sodium sulfate (6.10). Will be thick the reduced sample is added to the column and the graduated tube is washed with 2 ml of n-hexane (6.2) and added to the column. Will be 40 ml Hexane (6.2) was added to the dropping funnel, and the dropping funnel was connected to the column, the flow rate was adjusted to about 1 drop per second, Collect with a pear-shaped bottle.

For the substrate is relatively clean samples can also be purified using a commercial silica gel column (6.24). Use 10 ml before use Clean the silica gel column (6.24) with n-hexane (6.2). When the liquid level is 1 mm ~ 2 mm above the packing layer, concentrate Quantitatively transfer the sample to the purification column and rinse with 12 ml of n-hexane (6.2) to control the appropriate flow rate and receive with a graduated test tube.

8.4.2.3 desulfurization for sediment samples containing elemental sulfur, copper wire (beads) (6.19) were placed in the eluent to desulfurize and the copper surface became black After treatment with a nitric acid solution (6.12) to the surface of the copper metal luster, followed by water, acetone (6.4) and n-hexane (6.2) After washing, put it into the sample again and repeat several times until the surface of the copper does not turn dark.

8.4.3 concentrated volume the eluate was concentrated using a concentrator (7.4) to about 2 ml, transferred to a graduated tube and concentrated to a final volume of 1.0 ml, test.

Note. For soil samples with higher concentrations of PCBs or less interference, the extract can be directly transferred to n-hexane and concentrated to 2 ml left Right, all transferred to a column of silica gel (6.23) with 100 ml of n-hexane (6.2) elution, the eluate was collected, the volume was concentrated to 1.0 ml After testing.