Method for determining organochlorine pesticide residues in farmland soil through combination of ultrasound and gas chromatography

Abstract

The invention discloses a method for determining organochlorine pesticide residues in farmland soil through combination of ultrasound and gas chromatography. The method comprises the following steps:S1, sampling; S2, sample uniform mixing treatment; S3, extraction and salting-out; S4, oscillation mixing; S5, primary ultrasonic extraction; S6, secondary ultrasonic extraction; S7, primary concentration and purification; S8, secondary concentration and purification; S9, to-be-determined object making; S10, determination. The method has the advantages of being accurate in determination, high in sensitivity, simple and convenient to operate and the like. The chromatographic behavior study on DDT and metabolites thereof on a non-polar column HP-5 are also performed in the test, so that the accuracy is improved.

Description

technical field [0001] The invention relates to the related technical field of agricultural soil environment detection, in particular to a method for combining ultrasonic waves and gas chromatography to measure organochlorine pesticide residues in farmland soil. Background technique [0002] BHCs (BHCs) and DDTs (DDTs) are organochlorine pesticides (OCPs), which are representative persistent organic pollutants (POPs). Due to their good insecticidal effect and long-lasting effect, they have been widely used around the world. Although it was partially banned in my country in the 1980s, due to the semi-volatile and high persistence of organochlorine pesticides, they can exist in the atmosphere for a long time, spread over long distances through the distillation effect [3], and finally settle in the soil. It is still necessary to study the pollution status of densely populated areas. The Pearl River Delta region used to be an area where organochlorine pesticides were heavily use...

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Problems solved by technology

[0003] At present, my country has formulated the standard for the determination of OPCs in soil "GB / T 14550-2003 Gas Chromatography for the Determination of HCH and DDT in Soil". In this standard, the pretreatment extraction method is Soxhlet extraction, and the current common extraction method is There are also accelerated solvent extraction and microwave extraction, etc., but these methods have the disadvantages of long time consumption and large solvent consumption. For example, the extraction solvent volume of GB / T14550 mentioned above is 110mL, and special personnel are required to take care of it, and special equipment is required.

[0004] The pretreatment and purification methods in the national standard are concentrated sulfuric acid purification method or chromatography column purification method. The former uses concentrated sulfuric acid, and the operation has a greater risk; the latter needs to fill the chromatography column before the experiment, and the production method is cumbersome.

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