Determination of Methyl-Substituted Polycyclic Aromatic Hydrocarbons in Diesel Particulate-Related Standard Reference Materials

The concentrations of methyl-substituted polycyclic aromatic hydrocarbons (PAHs) in three diesel particulate-related Standard Reference Materials (SRMs) have been determined using multiple methods of analysis. These three SRMs--SRM 1650a, Diesel Particulate Matter; SRM 2975, Diesel Particulate Matter (Industrial Forklift); and SRM 1975, Diesel Particulate Extract--were recently issued by the National Institute of Standards and Technology. Each material has certified and reference concentrations for PAHs including many methyl-substituted compounds. Reference concentrations are available for 21 compounds in SRM 1650a, 20 compounds in SRM 2975, and 20 compounds in SRM 1975. The characterization of the methyl-substituted PAHs is described in this article in conjunction with a description of the relative distribution of the methyl-substituted PAHs in each material.