Page 51 - Volume 1, Issue 2, July 2008

GS/MS/MS determination of PAHs in water 103
el (0.1 μg/l) and 51.9-86% in the third for-
tification level (0.2 μg/l). The relatively low
recovery values for some of the examined
PAHs may be due to their lower solubility
in water (8), a fact that has also been ob-
served with the official EPA method (5).
Relative standard deviation values were
7.9-18.6%, 10.3-16.8% and 12.4-23.4%, in
the first, second and third fortification lev-
el respectively (Table 1), indicating a good
precision of the method. The limit of quan-
tification (LOQ) is equal to the lowest fortifi-
cation level (LOQ: 0.05 μg/l). At this level ac-
curacy and precision were acceptable.
During the quantitative analysis 2 mul-
tiple reaction monitoring (MRM) of 2 ions
from separate transitions of the molecular
ion were used. The 8 tested compounds
Figure 2. Chemical structures and mass spectra of 8 PAHs after injection in the GC/MS/MS system.