Certification of a diesel particulate related Standard Reference Material (SRM 1975) for PAHs

Standard Reference Materials (SRMs) are Certified Reference Materials issue d by the National Institute of Standards and Technology (NIST). Three of th ese materials, SRMs 1975 (Diesel Particulate Extract), 2975 (Diesel Particu late Matter, Industrial Forklift), and 1650 (Diesel Particulate Matter) are diesel particulate-related materials that are well characterized for PAH i somer distributions. SRM 1975 is a methylene chloride extract of industrial forklift diesel particulate matter and it was developed originally in resp onse to the needs of the bioassay community for a natural environmental ext ract. Thirty-nine PAHs (or combinations of PAHs) were determined in SRM 197 5 using various combinations of four different methods of analysis. SRM 197 5 will be issued with certified concentrations for eight PAHs. In addition, reference concentrations will be provided for additional PAHs, including m any alkyl substituted isomers such as methylphenanthrenes, methylpyrenes, a nd methylfluoranthenes. Reference values for the mutagenic activity of the extract will also be provided. The approach and results for the certificati on of PAH concentrations in SRM 1975 are described in this paper.