2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
Table I
LODs of individual PBDE congeners [ng ml –1 isooctane] for the GC/MS techniques tested
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GC/MS (EI) GC/MS (nCI)
Analyte PTV–GC/MS (EI) PTV–GC/MS GC/TOFMS (EI) PTV–GC/TOFMS
(splitless) (splitless) (nCI)
BDE 28 1.0 0.05 0.1 0.01 2.3 0.3
BDE 47 1.0 0.1 0.1 0.01 3.1 0.6
BDE 49 1.0 0.1 0.1 0.01 2.5 0.4
BDE 66 1.0 0.1 0.1 0.01 3.7 0.6
BDE 85 2.0 0.2 0.3 0.01 1.3 0.7
BDE 99 1.5 0.1 0.3 0.01 3.0 0.4
BDE 100 1.5 0.1 0.1 0.01 0.6 0.6
BDE 153 5.0 0.1 0.6 0.02 3.2 0.9
BDE 154 3.5 0.1 0.3 0.02 2.5 0.7
BDE 183 3.0 0.2 0.2 0.06 7.1 1.5
injection volume: multiple injection 2 × 10 μl
splitless period: 2 min.
The repeatability of the PTV–GC/MS injection,
expressed as a relative standard deviation (RSD, n = 10)
ranged from 3.8 to 6.3 % and 3.8 to 10.3 % for nCI and EI
mode, respectively. Similar RSD values for multiple injections
were obtained (3.8–9.2 % and 1.7–10.8 % for nCI and
EI mode, resp.) were determined for spiked fish lipid extract
(1 ng g –1 lipid weight).
LODs calculated as a quantity of analyte that generates
a response 3-time higher than the noise level of the detection
system (based on the injection of solvent standard solution
mixture) are summarized in Table I. LOQs were the minimum
concentrations of analytes that was possible to quantify
with acceptable accuracy and precision. Under these conditions,
the LOQ was the lowest calibration level and corresponded
for particular analyte to 3 × LOD. Generally, in nCI
mode, significantly lower LODs were obtained compared to
EI mode. On the other hand, the identification of individual
PBDEs was only based on their retention times. PBDEs are
eluted in order of increasing bromine number and intensity
Fig. 1. Chromatogram of mixed standard of PbDEs obtained
by GC/MS (NCI)
s446
of appropriate responses was obtained in following order in
case of GC/MS (nCI) system: BDE 28 > BDE 49 ~ BDE
47 ~ BDE 66 ~ BDE 100 > BDE 99 ~ BDE 85 ~ BDE
154 ~ BDE 153 > BDE 183 (see Fig. 1.). Similar chromatogram
obtained by PTV-GC/TOFMS (EI) is documented
in Fig. 2.
Fig. 2. Chromatogram of mixed standard of PbDEs obtained
by PTV–GC/TOFMS (EI)
Table I shows a significant reduction of LODs by almost
one order of magnitude (to values 0.01–0.06 ng ml –1 by the
use of PTV which allowed introduction of 1–250 µl of sample
(only 1–5 µl were injected by pulsed splitless).
PTV–GC/TOFMS provide LODs similar to PTV–GC/
MS (EI) and values were ranged from 0.3 to 1.5 ng ml –1 . The
main advantage of this technique is availability of full mass
spectral information for all sample components, i.e. confirmation
of target analytes.
Conclusions
In the present work, LODs of individual PBDE congeners
were reduced using various GC systems in analysis
of these analytes in various matrices such as environmental
samples (fish muscle, sediment etc.). Four different injection