1. Department of Environmental Science and Analytical Chemistry, Stockholm University, Svante Arrhenius väg 8, SE-106 91 Stockholm, Sweden
2. Mass Spectrometry Laboratory, Center for Physical Science and Technology, Savanoriu 231, LT-02300 Vilnius, Lithuania
3. Department of Ecology, Environment and Plant Science, Stockholm University, Svante Arrhenius väg 20, SE-114 18 Stockholm, Sweden