Optimization and application of GC-ICP-MS for the analysis of PBDEs in marine environmental samples: Challenges and sollutions Daniel Pröfrock and Andreas Prange, Helmholtz-Zentrum Geesthacht Zentrum für Material- und Küstenforschung, Institute of Coastal Research, Marine Bioanalytical Chemistry, Max-Planck Str. 1, 21502 Geesthacht, Germany daniel.proefrock@hzg.de The continuous and still growing anthropogenic impact on marine ecosystems recently results in a rising number of international agreements and new legislative requirements, which demand the monitoring of a wide range of both priority and new substances of concern steadily released into the aquatic environment. The quantification of pollution levels of different environmental compartments with either organic or inorganic contaminants as well as the measurement of individual body burdens of selected organisms at different trophic levels represents the “standard procedure” used, to derive information with respect to environmental assessment or for the status description of an ecosystems. Such quantitative analysis of priority hazardous substances in the environment becomes more and more a challenge since new legislations requires more sensitive methods for the determination of already defined priority compounds or newly emerging contaminants at low concentration levels. As an example the EU Water Framework directive (WFD) defines an EQS value for the sum of all PBDEs of 0.5 ng/L. For the reliable determination of PBDEs an LOQ smaller than 30 % of the EQS is required, which corresponds to an LOQ of 0.15 ng/L! For PBDE analysis HPLC-APCI-MS as well as GC-MS represent widely used methods. The main challenges for these methods are lower detection limits and the extension of the number of detectable congeners due to an improved chromatographic resolution. The application of ICP-MS as a (hetero)element specific detector for the sensitive determination of brominated flame retardants via their bromine content indicates some advantages. Here we describe the method development and optimization of GC-ICP-MS for the analysis of brominated flame retardants and its application for environmental related analysis of these priority compounds.