Total reflection X-ray fluorescence (TXRF) instrument

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This application is for a total reflection X-ray fluorescence (TXRF) instrument for the simultaneous analysis of metals from magnesium to uranium in the ultratrace range. The instrument should be able to analyze biological (thin sections) and aqueous samples as well as solids. This requirement profile reflects the broad orientation of the applying working group "applied aquatic toxicology", whose research focus on the one hand includes fundamental questions on the ecotoxicity of rare earth metals. Research goals are the development of a biotic ligand model for lanthanum and gadolinium, and the investigation of the effects of lanthanides on biological model communities. On the other hand, applied research topics include the elaboration of a system for ecotoxicological assessment of sediment quality of different rivers and coastal areas, and the development of a biological sensor for the detection of dumped chemical warfare agents in the Baltic Sea. All topics are united by the approach of focusing on the effect of bioavailable pollutants on organisms, using microorganisms, algae, nematodes, daphnia, and fish eggs as test organisms. Multielement analyses in small-volume samples drawn periodically from experimental set-ups are necessary to investigate contaminant-biota interactions, taking into account the natural variability associated with the use of living organisms in test systems. High sample throughput with high sensitivity and low cost are thus among the requirements for the system applied for. By using two excitation systems (molybdenum and tungsten), even environmentally relevant pollutants that are otherwise difficult to determine, such as cadmium, tin and antimony, can be measured in the ppb range. The sensitivity for lanthanides such as lanthanum and gadolinium is in the lower ppb range, as confirmed by preliminary measurements. The determination of bioaccumulation in organisms, among other things with the help of histological preparations, is possible with the system applied for. The acquisition of this device is intended to replace an older, existing device, which will then be used in teaching in the future.