Initially, known concentrations, about 10 ng lL1
, of pure individual
surrogate, internal standard and standard analytes solutions
were scanned between 50 and 600 m/z using the full-scan mode of
GC–MS. The quantitation and qualifier ions from the surrogate,
internal standard and authentic standards were selected and then
the mass spectral acquisition was done using selected ion monitoring
(SIM) with the Varian MS workstation version 6.9.3, with filament
delay set at 6 min. For surrogate (naphthalene-d8), the
quantitation ion m/z 136 (molecular ion) and qualifier ions m/z
108, and 54 were selected. In the case of IS, the quantitation ion
m/z 188 (molecular ion) and qualifier ions m/z 184, and 160 were
chosen. The ions monitored for the target compounds were illustrated
in Table 2.