Chemical ionization mass spectrometry of N-methylcarbamate insecticides, some of their metabolites, and related compounds.
The chemical ionization (CI) mass spectra with methane as the reagent gas are reported for 25 N-methylcarbamate insecticides or related compounds. The [M + 1]+ ions in the CI spectra are larger than the parent ions in the corresponding electron impact (EI) spectra of N-methyl- and N,N-dimethylcarbamates, but the contrary is true with N-hydroxymethylcarbamates. CI but not EI fragmentation of substituted-phenyl N-hydroxymethylcarbamates [ROC (O) NHCH2OH] appears to involve a 4-membered [ROC(O)NHCH2]+ intermediate which rearranges to give a [ROCH2]+ fragment. Other fragmentations unique to the CI spectra are also discussed.
D002219:Carbamates; D055598:Chemical Phenomena; D002621:Chemistry; D006900:Hydroxylation; D007306:Insecticides / Q000032:analysis* / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D008745:Methylation; D010573:Pesticide Residues / Q000032:analysis*
D002219:Carbamates; D007306:Insecticides; D010573:Pesticide Residues