M. Saha et al., GENERAL-METHOD FOR DETERMINING ETHYLENE-OXIDE AND RELATED N-7-GUANINEDNA-ADDUCTS BY GAS CHROMATOGRAPHY-ELECTRON CAPTURE MASS-SPECTROMETRY, Journal of chromatography, 712(2), 1995, pp. 345-354
Citations number
23
Categorie Soggetti
Chemistry Analytical","Biochemical Research Methods
A 112-mu g sample of DNA was spiked with 103 pg of N-7-(2'-hydroxyethy
l)guanine and 100 pg of N-7-(2'-hydroxyethyl-d4)guanine, the internal
standard. The sample was subjected to the following sequence of steps:
heating at 100 degrees C, precipitation of the DNA with HCl, reaction
with nitrous acid to form the corresponding xanthines, reaction twice
with pentafluorobenzyl bromide (first to derivatize NH, then OH), sol
id-phase extraction on silica and detection by gas chromatography-elec
tron capture mass spectrometry. The absolute, overall yield of final p
roduct for both the analyte and internal standard was 9.7%. Convenient
ly, the three chemical reactions are conducted sequentially in the sam
e vial and, aside from a washing step, are separated only by evaporati
ons. Corresponding N-7-guanine methyl, phenyl and styrene oxide adduct
s were detected at about the 50-ng level by the procedure, to indicate
the generality of the method.