Chromatographic techniques for petroleum and related products

Recent developments in chromatographic techniques for the separation and qu antitative characterization of petroleum and related products are highlight ed. Specifically, scope, applicability, and versatility of individual techn iques such as gas chromatography, liquid chromatography, supercritical flui d chromatography, thin-layer chromatography, and size-exclusion chromatogra phy are discussed in some detail. In general, analytical approaches vary wi dely depending on the chromatographic technique, instrumentation, minimum d etection limit, and sample type. Specific applications include chromatograp hic separation followed by identification and determination of individual c omponents, measurement of boiling range distribution, and determination of hydrocarbon group types. With the exception of gaseous samples and light di stillates (up to gasoline range materials), the inherent complexity arising from the presence of numerous isomers and compound types, and the finite r esolution afforded by chromatographic methods preclude precise identificati on and quantitative determination of individual components in fossil fuels and oils. For the middle and heavy distillates, chromatographic techniques have been applied mostly for the isolation and determination of compound cl asses. Several techniques such as open-column liquid chromatography, medium pressure liquid chromatography, high-performance liquid chromatography, an d supercritical fluid extraction provide separation of compound classes for subsequent characterization by high-resolution chromatography, spectroscop y, or other methods. Hyphenated or multitechnique chromatographic approache s have also been described. These simplify the characterization of complex samples by incorporating multiple separation mechanisms and detection schem es.