STRUCTURAL ELUCIDATION OF CLENBUTEROL-LIKE AND MABUTEROL-LIKE COMPOUNDS IN COMPLEX MATRICES USING SILYLATED AND N-BUTYLBORONATE DERIVATIVESBY GAS CHROMATOGRAPHY ELECTRON IMPACT AND CHEMICAL-IONIZATION MASS-SPECTROMETRY
F. Saltron et al., STRUCTURAL ELUCIDATION OF CLENBUTEROL-LIKE AND MABUTEROL-LIKE COMPOUNDS IN COMPLEX MATRICES USING SILYLATED AND N-BUTYLBORONATE DERIVATIVESBY GAS CHROMATOGRAPHY ELECTRON IMPACT AND CHEMICAL-IONIZATION MASS-SPECTROMETRY, Journal of mass spectrometry., 31(7), 1996, pp. 810-818
The mass spectra as their trimethylsilyl ethers and boronated derivati
ves under electron impact (EI) and methane chemical ionization conditi
ons of seven unauthorized beta(2)-agonists found in cattle feed are pr
esented. Structural elucidation was achieved through comparison with t
he standards clenbuterol, mabuterol and mapenterol. The structures of
brombuterol, bromoclenbuterol and bromomapenterol were deduced from th
eir isotopic patterns. Examination of fragments of boronated mabuterol
-like compounds under EI conditions involved the differentiation of tw
o isobaric compounds, mabexerol and 3-methylmapenterol, The amino subs
tituent of isopropylclenbuterol and isopropylbromoclenbuterol was obta
ined from clenbuterol, as these molecules specially fragment with a ne
utral dissociation of the side-chain, confirmed by tandem mass spectro
metry on a triple-guadrupole instrument. The branching structure of is
opropylclenbuterol was investigated by means of H-1 MMR experiments.