This paper is the result of ecological geological survey engineering.

Objective In the process of land reclamation implementation, it is necessary to establish a systematic standard detection method for the evaluation of land reclamation quality, and the requirements for the limit of detection of various pollutants are more stringent. As a kind of persistent pollutant, organochlorine pesticides are an important detection index. When adopting the methods such as gas chromatography, gas chromatography-mass spectrometry for the detection of organochlorine pesticides, there are problems such as false positive and low sensitivity.

Methods In this paper, the extraction and purification methods of reclaimed land soil samples were optimized to solve the actual problems such as complex matrix and many interference factors of reclaimed land soil samples; the gas chromatography-triple quadruple mass spectrometry analysis method for 14 kinds of organochlorine pesticides in reclaimed land soil samples was established by using the mass spectrometry multiple reaction monitoring mode (MRM) for scanning to improve the sensitivity and accuracy of the method, to ensure the reproducibility, and to avoid false positive. The method used n-hexane: Acetone (1:1) as the extractant, accelerated solvent extraction (ASE) for pretreatment, silica gel mini-column purification, multiple reaction monitoring mode (MRM) scanning, internal standard method for quantitative analysis, and gas chromatography-triple quadruple mass spectrometer for determination.

Results The addition recovery of the method was 79.64%-104.56%, and the limit of detection was 0.10-0.404 μg/kg. Compared with the use of mass spectrometry full scan or selected ion mode, the mass spectrometry multiple reaction monitoring mode had higher sensitivity and accuracy; the repeatability standard deviation and reproducibility standard deviation of the actual sample detection and the collaborative experiment results all met the specifications requirements, and the reproducibility of the method was more stable.

Conclusions The method could effectively remove the interference of complex matrix of reclaimed land soil samples, meet the detection requirements of low content level of pollutants in reclaimed land samples, and apply to the detection of organochlorine pesticides in reclaimed land soil samples.