Use of a hybrid sputtering ion source for the determination of the bio-derived carbon fraction in particulate matter

The development of analytical methods capable of discriminating between bio-derived and fossil-derived carbon in Particulate Matter (PM) is a crucial aspect in the general efforts of identifying effective strategies for health-risks mitigations. The large difference in the isotopic signature between bio-derived and fossil derived materials in term of the concentration of C-14 the radioactive carbon isotope can be effectively used for this purpose. Indeed, though the detection and measurement of C-14 by AMS (Accelerator Mass Spectrometry) is a well established methodology, the reduced amount of carbon in PM samples (typically in the mu g range) requires the use of proper ion sources with a high efficiency. We present here the set-up developed at CEDAD-University of Salento as based on a gas-accepting hybrid ion source and an in-house designed gas handling interface. The performances of the system are also shown by presenting the firsts tests carried out on PM sampled on quartz filters in Lecce, Italy.