HJ 648-2013Water quality. Determination of nitroaromatics by gas chromatography (English PDF)

Foreword

To protect the environment and protect the human body 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 Prevention and Control this standard is established for the determination of healthy, standardized nitrobenzene compounds in water.

This standard specifies the liquid-liquid extraction and solidification of nitrobenzene compounds in surface water, groundwater, industrial wastewater, domestic sewage and seawater.

Phase extraction gas chromatography.

This standard is for the determination of water nitrobenzene, nitrotoluene, nitrochlorobenzene, dinitrotoluene by gas chromatography (GB 13194-91) Revision.

This standard was first published in 1991. The original drafting unit was the Wuhan Environmental Monitoring Center Station. This is the first revision. This revision the main content is.

-- Amend the standard name to "Determination of water-nitrobenzene compounds by liquid-liquid extraction/solid phase extraction - gas chromatography".

-- Increased the type of measurement of nitrobenzene compounds.

-- Expanded the scope of application of the method and increased the determination of domestic sewage and seawater.

-- Added sample preparation methods for solid phase extraction.

-- The analytical column was changed from packed column to capillary column, and the chromatographic conditions were changed accordingly.

- Liquid-liquid extraction solvent changed from benzene to toluene.

-- Modified the quantitative method for nitrobenzene compounds.

-- Modified the method detection limit.

-- Added quality assurance and quality control provisions.

Gas chromatographic method for the determination of nitrobenzene, nitrotoluene, nitrochlorobenzene and dinitrotoluene from the date of implementation of this standard (GB 13194-91) abolished.

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 was drafted. Tianjin Environmental Monitoring Center, Environmental Standards Institute of the Ministry of Environmental Protection.

This standard is verified by the National Key Laboratory of Environmental Pollution Control, Environmental Monitoring Center of Shenyang, and Environmental Protection of the Ministry of Agriculture.

Environmental Protection Monitoring Institute, Tianjin Tanggu District Environmental Protection Monitoring Station, Tianjin Dongli District Environmental Protection Monitoring Station and Tianjin Dagang District Environmental Protection Monitoring station.

This standard was approved by the Ministry of Environmental Protection on June 3, 2013.

This standard has been implemented since September 1, 2013.

This standard is explained by the Ministry of Environmental Protection.

Water quality - Determination of nitrobenzene compounds - Liquid-liquid extraction/solid phase extraction - Gas chromatography

1 Scope of application

This standard specifies liquid-liquid extraction and solid phase extraction gas chromatography for the determination of 15 nitrobenzene compounds in water. 15 nitrobenzenes the compounds include nitrobenzene, p-nitrotoluene, m-nitrotoluene, o-nitrotoluene, p-nitrochlorobenzene, m-nitrochlorobenzene, o-nitrochloride.

Benzene, p-dinitrobenzene, m-dinitrobenzene, o-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 3,4-dinitrotoluene, 2,4-Dinitrochlorobenzene, 2,4,6-trinitrotoluene.

This standard applies to the determination of nitrobenzene compounds in surface water, groundwater, industrial wastewater, domestic sewage and seawater.

The sampling amount of liquid-liquid extraction method is.200ml, the detection limit of the method is 0.017µg/L~0.22µg/L; when the sampling amount of solid phase extraction is 1.0L, the detection limit of the method was 0.0032µg/L~0.048µg/L. See Appendix A for details.

2 Normative references

The contents of this standard refer to the terms in the following documents. For undated references, the valid version applies to this standard.

GB 17378 Ocean Monitoring Code HJ/T 164 Technical Specifications for Groundwater Environmental Monitoring HJ/T 91 Surface Water and Wastewater Monitoring Technical Specifications

3 Principle of the method

Liquid-liquid extraction. The nitrobenzene compound in the water is extracted with a certain amount of toluene, and the extract is subjected to dehydration, purification, and chromatographic analysis.

Solid phase extraction. adsorption of nitrobenzene compounds in water by solid phase extraction column or extraction disk, elution with n-hexane/acetone, eluent After dehydration and constant volume, chromatographic analysis was carried out.

The extract is injected into a gas chromatograph, and the target compound is separated by a quartz capillary column and determined by an electron capture detector.

Qualitative, external standard method quantitative.

4 Interference and elimination

4.1 Organic compounds such as organochlorine pesticides (hexachlorocyclohexane, DDT), halogenated hydrocarbons, chlorobenzene, etc., which may coexist in the water sample, are on the electron capture detector.

Although there is a response, there is no significant interference with the method in the method due to the difference in retention time.

4.2 Other substances in the water that may be co-existing with halogen or nitrogen in the electron capture detector may interfere with the determination, and the polarity is poor.

If the two larger capillary columns are separated and measured separately, the qualitative error can be greatly reduced.

4.3 For samples with complex background interference, qualitative determination can also be carried out using gas chromatography mass spectrometry.

5 Reagents and materials

Analytical purification reagents that meet national standards are used for analysis, unless otherwise stated. The test water is freshly prepared deionized water or steamed.

Distilled water.

5.1 n-Hexane (C6H14). Chromatographically pure.

5.2 Acetone (C3H6O). chromatographically pure.

5.3 Methanol (CH4O). Chromatographically pure.

5.4 Toluene (C7H8). chromatographically pure.

5.5 anhydrous sodium sulfate (Na2SO4). baked in an oven at 450 ° C for 4 h, placed in a desiccator cooled to room temperature, filled into a bottle, dried Saved in the device.

5.6 Hydrochloric acid (HCl). rho (HCl) = 1.19 g/ml.

5.7 Sodium hydroxide (NaOH).

5.8 Nitrobenzene compound standard substance. the purity is not less than 98%.

Including nitrobenzene, p-nitrotoluene, m-nitrotoluene, o-nitrotoluene, p-nitrochlorobenzene, m-nitrochlorobenzene, o-nitrochlorobenzene, p-Dinitrobenzene, m-dinitrobenzene, o-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 3,4-dinitrotoluene, 2, 4-two Nitrochlorobenzene, 2,4,6-trinitrotoluene standard material.

5.9 nitrobenzene standard stock solution. rho =10.0mg/ml.

Accurately weigh 250mg of each nitrobenzene compound standard (5.8), accurate to 0.1 mg, and put 25.0ml brown capacity in the bottle, use a small amount of toluene (5.4) to help dissolve, add n-hexane (5.1) to the mark, as a standard stock solution of nitrobenzene, at 4 ° C Save for one year. Commercially available certified standard solutions are also available.

5.10 nitrobenzene standard use liquid. nitrobenzene and nitrotoluene rho =.200mg/L; nitrochlorobenzene, dinitrotoluene, dinitrochlorobenzene and Trinitrotoluene rho = 20.0 mg/L.

Accurately transfer.200 µl each of nitrobenzene and nitrotoluene standard stock solution (5.9), nitrochlorobenzene, dinitrotoluene, dinitrochlorobenzene and 20.0 µl of the standard stock solution of trinitrotoluene (5.9), in a 10.0 ml brown volumetric flask, make up to volume with n-hexane, mix and mix the standard use solution can be stored for half a year at 4 °C.

5.11 Solid phase extraction column elution solution. 3 1 (V/V) n-hexane/acetone mixed solution.

5.12 Hydrochloric acid solution. 1 1 (V/V).

5.13 Sodium hydroxide solution. c (NaOH) = 0.1 mol/L.

4 g of sodium hydroxide (5.7) was dissolved in a small amount of water and diluted to 1000 ml.

5.14 Solid phase extraction adsorbent. 60~80 mesh, the matrix material is polystyrene-divinylbenzene spherical polymer copolymer. For example. HLB or GDX502. In the Soxhlet extractor, acetone, n-hexane and methanol were successively extracted for 6 hours, then dried in an oven at 100 ° C, and transferred to Cool to room temperature in a desiccator and store in a screw-capped glass vial with a ground glass stopper or a lined Teflon pad.

5.15 Silica-magnesium type adsorbent. for chromatography, 60~80 mesh, purchase 677 °C activated product, stored in a glass stopper with a ground or with a lined poly 4 Fluorine vinyl mat in a screw cap glass bottle container.

Activation of the silica-magnesium type adsorbent. the silicon-magnesium-type adsorbent is placed in a large porcelain crucible and spread out, and the upper part of the porcelain crucible is covered with aluminum foil, and the crucible is placed.

Into the oven, dried at 130 ° C for 16 h, then placed in a desiccator in a desiccator cooled to room temperature, sealed glass Waiting for use in the bottle.

5.16 Carrier gas. nitrogen, the purity is not less than 99.999%.

6 Instruments and equipment

6.1 Gas chromatograph with temperature programmed function and electron capture detector (ECD).

6.2 Solid phase extraction unit.

6.3 Soxhlet extractor.

6.4 Muffle furnace.

6.5 oven.

6.6 Dryer.

6.7 Precision balance. The sensitivity is 0.1mg.

6.8 Column 1. fused silica capillary cross-linked 100% dimethyl with a column length of 60 m, an inner diameter of 0.32 mm and a film thickness of 1.0 µm Polysiloxane columns (such as HP-1) and columns with similar properties.

Column 2. fused silica capillary cross-linked 14% cyanopropyl group with a column length of 30 m, an inner diameter of 0.25 mm and a film thickness of 0.25 µm Benzene and 86% dimethylpolysiloxane columns (such as DB-1701) and columns with similar properties.

6.9 Solid phase extraction column. A solid phase extraction column packed with solid phase extraction adsorbent (5.14) (500mg~1000mg). Or use the same class Commercial solid phase extraction column for type packing.

Pretreatment of the solid phase extraction column. The solid phase extraction column is placed on the needle seat of the solid phase extraction device, and the extraction column is pre-washed with 5 ml of n-hexane.

5 ml of methanol was added, and after the methanol was completely passed through the extraction column, 5 ml of water was added to leave the bed in a wet and activated state.

6.10 Drying column. 2 g of anhydrous sulfur is packed into the drying column (column length about.200 mm, inner diameter 6~10 mm) with sieve plate or glass wool at the bottom.

Sodium (5.5). The column should be rinsed with 10 ml of toluene or n-hexane before use to purify the dried column.

6.11 Silica-magnesium purification column. 60mm (column length) × 15mm (internal warp) glass or polyethylene column, with a thick hole glass sand core at the bottom.

Packing of the purification column. 1000mg activated silicon-magnesium type adsorbent (5.15) is placed in a 50ml beaker, and an appropriate amount of n-hexane is added.

Acetone (5.11), a silica-magnesium type adsorbent was prepared as a suspension. The suspension is then poured into a purification column and the purification column is tapped to fill the adsorbent.

(Commercial purification columns of the same type of packing can also be used).

6.12 Vial. 1L brown with ground stopper glass bottle.

6.13 Microinjectors. 100 µl, 50 µl and 10 µl.

6.14 separatory funnel. 0.1L, 0.5L, 1L or 2L.

6.15 Receiver. 10ml or 20ml with a graduated scale.

6.16 Common instruments used in general laboratories.

7 Samples

8 Analysis steps

9 Calculation and representation of results

10 Precision and accuracy

11 Quality Assurance and Quality Control