Chromatographic Methods of Analysis for the Determination of PAHs in Environmental Samples

Abstract

Polycyclic aromatic hydrocarbons (PAHs) constitute a class of compounds that are known to exhibit mutagenic and carcinogenic properties. As a result, PAHs are frequently measured in environmental compartments such as the atmosphere, freshwater and marine surface waters and sediments, and in biological tissues and terrestrial matrices such as oyster tissue, soils, and vegetation. Measurements often require difficult analytical chemistry schemes because environmental PAHs typically lack distinct functional groups and exist with numerous structural isomers. Therefore, analytical methods must offer isolation, separation, and detection capabilities for compounds that exist as multi-component mixtures. The Analytical Chemistry Division at the National Institute of Standards and Technology (NIST) has been involved in the development and use of liquid and gas chromatography (LC and GC, respectively) methods for the determination of PAHs since the early 1970s as part of the development of standard reference materials (SRMs) for the measurement of PAHs in environmental samples. In this chapter, recent NIST experiences in the use of LC and GC methods for the determination of PAHs in environmental samples are presented. Specifically, LC and GC techniques are discussed including a review on the selection of an appropriate LC column for the separation of PAHs, approaches for the determination of PAHs in environmental samples by LC techniques (selective detection using fluorescence spectroscopy and isomer fractionation techniques), and conventional and novel GC techniques (PAH separations using phenylmethylpolysiloxane and liquid crystalline stationary phases, respectively). Case studies are presented for the determination of PAHs in a diesel particulate extract and two marine sediment standard references materials. The results of LC and GC measurements of PAHs are discussed, and the applicability of the various approaches are compared. In addition, coupled LC-GC and supercritical fluid chromatography (SFC) are examined as alternative approaches for the measurement of PAHs in environmental samples.