Giuseppe Ianiri, Alessandra Fratianni, Pasquale Avino, Gianfranco Panfili

Dipartimento di Agricoltura, Ambiente e Alimenti, Università degli Studi del Molise, 86100 Campobasso, Italy.

Recently, numerous studies have been performed regarding the use of plants to assess the contamination status of an area. A plant that can be used for this purpose is Malva sylvestris. Among the organic micropollutants polycyclic aromatic hydrocarbons (PAHs) are usually determined. These are released into the environment as a result of emissions from combustion sources and industrial processes. International Agency for Research on Cancer has drawn specific attention to benzo[a]pyrene which is in Group 1, namely carcinogenic compounds to humans. This contribution would like to show the development and the related optimization of a rapid and simple analytical method for the qualification and quantification of PAHs in M. sylvestris leaves. 

The PAHs extraction is carried out by means of an ultrasonic bath after the addition of a suitable organic solvent. Extracts are then passed over anhydrous sodium sulfate and concentrated first by rotary evaporator and then under light nitrogen flow. Finally, a known volume of internal standard (deuterated perylene D12, 98% chrysene D12, 98%) is added, and 1 µL of extract was injected into GC-MS with a single quadrupole analyzer (GC-6890/MSD-5973). The authors optimized experimental parameters in order to achieve significant recovery of the analytes. Specifically, the recoveries of analytes were evaluated according to the extraction solvent. To evaluate the extraction efficiency, five organic solvents were tested. Three extractions were performed for each solvent. Figure 1 shows the average percent recoveries (R%) along with standard deviations (s.d.).

Among the solvents used, cyclohexane allows for the highest recoveries (from 62.3 to 104.2 %). The developed analytical method shows excellent recoveries of analytes under the best experimentally determined conditions. In conclusion, the method is rapid, sensitive and accurate and will be applied later on a wide range of real samples to assess the contamination status of territories with different anthropogenic impact.

Keywords: polycyclic aromatic hydrocarbons, GC/MS, environmental pollution, malva sylvestris

References

1. Yang M, Tian S, Liu Q, Yang Z, Yang Y, Shao P, Liu, Y Toxics, 10 (2022) 634. DOI: 10.3390/toxics10110634