Preparation of Certified Reference Materials of Organochlorine Pesticides and Polychlorinated Biphenyls in Chinese Typical Soils

In China, there is only one certified reference material (CRM) of organochlorine pesticide (OCPs) and three CRMs of polychlorinated biphenyls (PCBs) in soil. Internationally, there is one CRM of OCPs and two CRMs of PCBs in soil in Europe. The National Institute of Standards and Technology (NIST) of the USA, the National Metrology Institute of Japan (NMIJ), and the International Atomic Energy Agency (IAEA) have developed sediment CRMs for OCPs, PCBs and polycyclic aromatic hydrocarbons (PAHs). However, the matrix and contamination levels of CRMs of OCPs and PCBs do not match with the actual pollution of soil in China.In this study, according to the distribution of soil types, pollution levels of organic compounds and quality control requirements of soil samples, the typical soils were collected as candidates in China. According to the primary standard material specification, 6 CRMs of OCPs and PCBs in different soil types (GBW07469-GBW07474) have been developed. Based on the results from traditional methods including Gas Chromatography-Electron Capture Detector (GC-ECD), Gas Chromatography-Mass Spectrometry (GC-MS), Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) and new techniques of Gas Chromatography-Isotope Dilution Mass Spectrometry (GC-IDMS), Gas Chromatography-Isotope Dilution Tandem-Mass Spectrometry (GC-IDMS-MS), certified values and expanded uncertainty for 8 OCPs and 7 PCBs are given. Meanwhile, a GC-ID-HRMS method was used to determine PCBs in candidate reference materials for comparison and validation. These CRMs cover most Chinese soil types, including cinnamon, paddy, yellow and meadow soil. The certified values of OCPs and PCBs in soils range from 3.9 μg/kg to 2.31 mg/kg. As the soils used for CRMs were collected from the field, the matrix and contamination levels of OCPs and PCBs are consistent with actual soils. The CRMs can be used in the quality control of OCPs and PCBs detection in soils of different pollution levels in different regions.