ESI and APCI LC-MS/MS in Model Investigations on the Absorption and Transformation of Organic Xenobiotics by Poplar Plants (Populus alba L.)

Populus alba Villafranca clone was chosen for a proof of concept study to determine the potential uptake and accumulation of xenobiotics by trees. Caffeine, erythromycin, and sodium dodecyl sulphate (SDS) were studied as representative elements of, respectively, widely present organic pollutants, antibiotics, and surfactants. Plants were grown hydroponically and irrigated with a recirculating Hoagland's nutrient solution (control) and Hoagland's nutrient solution fortified with the desired pollutant. Different plants’ tolerance was observed in relation to xenobiotics applied. Under caffeine and erythromycin treatments, plants showed good health all over the period of experiments, and no differences in poplar growth were observed. On the contrary diffused necrosis at leaves’ level was observed when SDS was applied to nutrient solution. Xenobiotics uptake was investigated in roots, stem, and leaves, and quantification was performed using liquid chromatography, coupled with tandem mass spectrometry using selected reaction ion monitoring on a triple quadrupole mass spectrometer, with electrospray or atmospheric pressure chemical ionization, depending on the analyte. All the pollutants were detected in all organs analyzed. Poplar plants also showed an active role in the elimination of the pollutants as some of them were metabolized by the tree.