ABSTRACT
Some xenobiotics are resistant to degradation. Xenobiotics such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons (PAHs), and trichloroethylene accumulate in the environment due to their recalcitrant properties and have become an environmental concern due to their toxicity and accumulation. A xenobiotic is a chemical substance found within an organism that is not naturally produced by or expected to be present within. Xenobiotics may be grouped as synthetic organochlorines such as plastics and pesticides, or naturally occurring organic chemicals such as PAHs and some fractions of crude oil and coal. A correct determination of xenobiotics residues at the trace level is still a significant challenge for analytical chemists. A successful xenobiotic analysis depends on the availability of the instrumentation in the laboratory and on the selection of a suitable chromatographic method. The retention of xenobiotics in ion-pair chromatography systems can be controlled by changing the type or concentration of the ion-pair reagent and the organic solvent in the mobile phase.
