Preparation and certification of two freshwater sediments certified reference materials for polycyclic aromatic hydrocarbons

Abstract

Two freshwater sediments certified reference materials (CRMs) for 16 polycyclic aromatic hydrocarbons (PAHs) have been developed by the Institute for Environmental Reference Materials (IERM) of Ministry of Environmental Protection (MEP) in China. The methodology for preparing the CRMs of PAHs in sediments is described in this paper. The collected natural sediment samples were air-dried, ground, homogenised, packed, sterilised and tested on stability and homogeneity. Homogeneity results showed that the between-unit variation was confirmed to be below 4.5% for each compound. Stability was assessed after storage of samples for 16 months at temperature less than 30°C and in shade. The certification of the natural sediment matrix CRMs for PAHs was based on the agreement of results using different analytical techniques including gas chromatography/mass spectrometry (GC/MS) and reversed-phase liquid chromatography (LC) by no less than eight collaborating laboratories including IERM. Results of the homogeneity showed that the calculated u_bb′ was 0.9–2.5% for environmental river standard-4 (ERS-4) and 9–2.3% for environmental lake standard-1 (ELS-1), whereas stability results of total 16 PAHs indicated that the calculated u_rel,lts was 4.2% for ERS-4 and 2.2% for ELS-1. Certified values of 16 PAHs in ERS-4 varied from 8.5 to 167 μg/kg and ranged from 0.036 to 2.8 mg/kg in ELS-1.The good comparability, together with the independent confirmation of the assigned mass fraction by using different methods, confirmed that the CRMs are suitable for the method validation and quality control in soil or sediments analysis.

Keywords:

• polycyclic aromatic hydrocarbons (PAHs)
• certified reference materials (CRMs)
• sediment
• certification

Acknowledgements

All laboratories for their participation in the certification exercises and comparison are acknowledged:

National Research Center for Environmental Analysis and Measurement, China; National Research Center for Geoanalysis, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Science; Nanjing Environmental Monitoring Center Station, China; Shanghai Environmental Monitoring Center, China; Tianjin Environmental Monitoring Center, China; Jiangsu Province Environmental Monitoring Center, China; Zhejiang Province Environmental Monitoring Center, China; Harbin Environmental Monitoring Center Station, China; Hangzhou Environmental Monitoring Center Station, China; National Institute of Standards and Technology, USA; and Environmental Science and Technology Center, Canada.

Additional information

Funding

This work was supported by Environmental Protection Research Special Funds [200709043].