Photochemical sample treatment: A greener approach for PCBs analysis in sediments

Electrical installations and industrial outlets are the major source in environment of chlorinated organic compounds. These are distributed in several geographical areas through long-range atmospheric transport and deposition. Additionally, chlorinated organic compounds can be introduced in the food chain and reach the consumers in very high levels. Besides toxicological studies on PCBs, recent research is focusing on more sophisticated analytical methods for PCBs detection. Distribution and dispersion of PCBs mostly occur through air, water, soils, and sediments. The latter are complex matrices whose analysis often involves costly extraction and purification procedures. In particular, PCBs are separated from environmental matrices by complete extraction with organic solvents, such as dichloromethane, hexane, acetone, or a combination of them. Sample purification can be considered the most polluting step of the whole analytical process for PCBs determination in sediment samples. The use of photochemical methods for sample purification represents a state-of-the-art technique in Green Analytical Chemistry. In this work, first application of photochemical sample treatment for the selective removal or reduction of organic substances interfering with PCBs analyses in the sediments is reported. The method efficiency and robustness was compared with currently used chromatographic purification. Results based on the analysis of real and certified samples showed similar or improved detection thresholds and pointed out the advantages of the photochemical methodology in terms of costs and environmental friendly conditions.