title: Investigation on the chemical structure of nonextractable residues of the fungicide cyprodinil in spring wheat using 13C-C1-phenyl-cyprodinil on 13C-depleted plants-an alternative approach to investigate nonextractable residues.
abstract: 13C-labelled cyprodinil was applied on 13C-depleted wheat plants with 27-fold field application rate. A control experiment applying same amounts of 14C-cyprodinil showed that main portions of the residues were detected in the cellulose (15% NER), hemicellulose (28.3% NER), and lignin fraction (23.3% NER). 16.7% were detected in water soluble polymers, 6% in both, pectin and protein fraction, and 4% in the starch containing fraction. Free cyprodinil was detectable by TLC in all fractions except lignin. A direct characterization of the residues in vivo by CP-MAS was not successful. Cell wall fractions were further analysed by liquid state NMR to determine the structure of the mobilized highly polymer/polar residues: Within lignin, where most of the residues were located at field application rate, neither intact cyprodinil nor its metabolites could not be detected. The 13C-label introduced was probably incorporated in the polymer as natural lignin monomers and thus are not considered as bound residues according to IUPAC definition.
authors.affiliation: Department of Biology V-Environmental Chemistry, Technical University of Aachen, Aachen, Germany. t.ertunc@nercrcl.gla.ac.uk
authors.forename: Tanya
authors.initials: T
authors.lastname: Ertunç
authors.forename: Burkhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Holger
authors.initials: H
authors.lastname: Kühn
authors.forename: Marco
authors.initials: M
authors.lastname: Bertmer
authors.forename: Andreas
authors.initials: A
authors.lastname: Schäffer
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis; D002473:Cell Wall; D005506:Food Contamination; D010573:Pesticide Residues / Q000032:analysis* / Q000737:chemistry; D011743:Pyrimidines / Q000032:analysis* / Q000737:chemistry; D014908:Triticum / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D010573:Pesticide Residues; D011743:Pyrimidines; C108338:cyprodinil