Pentafluorobenzylation of the fungicide metabolite fenpropimorphic acid for GC/MS investigations of soil samples.
For the determination of fenpropimorphic acid in soil samples, a derivatization step with pentafluorobenzylbromide has been established in order to perform GC/MS with negative chemical ionization. In spite of forming the electrophilic pentafluorobenzyl ester, only the fenpropimophic acid anion was detected. Additional derivatization reactions with diazomethane and 2,2,2-trichloroethanol showed that the formation of this acid anion was depending on the leaving group. In comparison with the determination of the methyl ester with GC/MS and electron impact ionization, the detection limit was however improved from 10 microg/kg to 2 microg/kg dry soil and the analytical quality was ensured due to higher stability of the pentafluorobenzyl ester standards.
Dieckmann
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H
Institute of Ecological Chemistry and Waste Analysis, Technical University of Braunschweig, Hagenring 30, D-38106, Braunschweig, Germany.
Kreuzig
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R
Bahadir
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M