Analysis of biotic matrices by Laser-Induced Breakdown Spectroscopy

This bachelor thesis discusses the possibility of using Laser-induced breakdown spectroscopy (LIBS) for biological application. The LIBS method was used to determine spatial distribution of a chosen element, cadmium, in selected model plant, white mustard (Sinapis Alba L.) The exposure took place in hydroponic conditions and lasted for 72 hours, therefore it was an acute toxicity test. Three different sources of cadmium were tested, mercaptopropionic acid stabilized quantum dots (CdTe QDs), silica coated quantum dots (CdTe/SiO2 QDs), and cadmium chloride, which was used as a positive control. After the exposure and before determination of the spatial distribution of cadmium in plants, a significant portion of the thesis was devoted to optimization of selected parameters of LIBS measurement (laser energy and gate delay). Subsequently, the cadmium distribution was determined and the obtained results were discussed with regards to the tested substance, its stability and its tendency to aggregate/agglomerate in water medium in contact with testing organism during exposure. In the final part of the work, the suitability of the LIBS method for the determination of spatial distribution of chosen contaminants was evaluated