Polycyclic aromatic hydrocarbons (PAHs) are widespread contaminants generated primarily during the incomplete combustion of organic materials (e.g. coal, oil, petrol, and wood). These organic compounds are mostly made of hydrogen and carbon in the form of two or more fused aromatic rings. PAHs have been proven to be harmful to human health and should be avoided.
Rivers and other flowing waters are mainly polluted by PAHs which may affect water life forms due to their cancerous, mutagenic and teratogenic effects, according to the Environmental Protection Agency (EPA), which is why they, along with the European Environment Agency, listed PAHs as priority pollutants. Concentrations of PAHs in surface water are directly linked to their bioaccumulation in the food chain. PAHs are highly lipid soluble compounds and hence quickly absorbed from the gastrointestinal tract of mammals, which are later distributed through the body with a tendency for localization in the fat tissue.
For the sake of the environment, analytical procedures have been developed in order to monitor the concentrations of PAHs in water, air, soil, agricultural products and almost everywhere in the environment. Each analytical procedure consists of several important steps – sampling, sample treatment, isolation of the target compounds, identification, quantification, and data handling. Operations carried out with samples before the instrumental analysis are considered to be a part of the sample preparation, which includes the required treatments in order to optimize the sample for further examination. The extraction process is often included as one of the necessary treatments in order to increase the precision and accuracy of the analytical method.
These days, sample preparation procedures tend to follow the ideology of the Green Analytical Chemistry (GAC), reducing or—in the best case—removing the potential harmfulness of analytical practices on operators and the environment. GAC is focused on developing instruments and methods that leave less hazardous waste behind and thus are environment-friendly and—more importantly—safer for practical use.
Last but not least, the cost of the analysis can sometimes stand in the way of conducting good-quality research, which is why scientists are working on developing methods that are both effective and less expensive. Having that in mind, the review paper published in our journal (CN: 1(1), 93-123) describes the sample preparation techniques suitable for the extraction of PAHs from water—and following the GAC principles—as well as the further examination of the sample.