1 DDT
1.1 Packed column gas chromatography
1.1.1 Scope
This standard specifies the packed column gas chromatography for determination of DDT and isomers of hexachlorocyclohexane in drinking water and its source water.
The method is applicable to the determination of DDT and isomers of hexachlorocyclohexane in drinking water and its source water.
The minimum detectable mass of the method: 6.0 pg for DDT and 2.0 pg for isomers of hexachlorocyclohexane; the minimum detectable mass concentration: 0.03 μg/L for DDT and 0.008 μg/L for isomers of hexachlorocyclohexane, if 500mL of water sample is taken for determination.
Under selected analysis conditions, the method is favorable in separating effects to DDT and isomers of hexachlorocyclohexane with little interference.
1.1.2 Principle
DDT and isomers of hexachlorocyclohexane are extracted with cyclohexane from water, concentrated, and then separated and determined using gas chromatograph with electron capture detector.
1.1.3 Reagents and Materials
1.1.3.1 Carrier gas and auxiliary gas: nitrogen (99.999%).
1.1.3.2 Reagents used in preparation of standard sample and sample pretreatment.
1.1.3.2.1 Cyclohexane or petroleum ether: redistill with complete glass distiller until there is no interference peak appearing during determination.
1.1.3.2.2 Benzene, chromatographic pure.
1.1.3.2.3 Anhydrous sodium sulfate (Na2SO4): baked for 4h at 350℃, placed in the desiccator for use.
1.1.3.2.4 Sulfuric acid (ρ20=1.84 g/mL): guaranteed reagent.
1.1.3.2.5 Sodium sulfate solution (40 g/L): weigh 4g of anhydrous sodium sulfate (1.1.3.2.3), dissolve it in pure water and dilute to 100mL.
1.1.3.2.6 Chromatogram reference material: reference materials of DDT and isomers of hexachlorocyclohexane are all chromatographic pure.
1.1.3.3 Reagents used in preparation of chromatographic columns.
1.1.3.3.1 For chromatographic columns and fillers, see the relevant content in 1.1.4.1.3.
1.1.3.3.2 Solvent used in coating stationary liquid: dichloromethane (CH2Cl2).
1.1.4 Instruments
1.1.4.1 Gas chromatograph.
1.1.4.1.1 Electron capture detector: Ni-63 source or deuterium source.
1.1.4.1.2 Recorder or workstation.
1.1.4.1.3 Chromatographic column
A Type of chromatographic column: hard glass packed column with the length of 2m and the inner diameter of 3mm.
B Filler
