3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
of target compouds was possible using peak abundancies of
deconvoluted peaks at their particular uniqu masses.
M e t h o d s P e r f o r m a n c e
C h a r a c t e r i s t i c s
Relevant performance characteristics of the analytical
methods (repeatability, LOD/LOQ and linearity) were tested
on spiked samples in three replicates. As long as this work
was mainly focused at the final determinative step of the
whole analytical process, issues associated with sample preparation
(such as recoveries) were not discussed. The results
are summarized in Table II.
Table II
Method performance characteristics of selected analytes in
various food matrices analyzed by GC-HT TOF MS. LOQs
were estimated in purified matrix extracts or in water (for
BPDEs). Repeatability (RSD) was measured at 25 µg dm –3
Compound Linearity LOQ RSD
(R2) [µg dm –3 ] (n =3 , [%])
Pesticides in baby food
HCB 0.9991 2.5 2
DDT 0.9994 5 5
DDE 0.9981 5 7
DDD 0.9980 5 9
lindan 0.9995 2.5 4
endrin 0.9993 5 4
chlorpiryfos 0.9975 5 6
heptachlor 0.9972 5 8
PCBs in pork fat
PCB 28 0.9983 2.5 5
PCB 52 0.9963 5 9
PCB 101 0.9955 5 6
PCB 118 0.9959 5 10
PCB 138 0.9960 5 5
PCB 153 0.9942 10 12
PBDEs in water
BDE-28 0.9987 0.005 2
BDE-47 0.9954 0.001 4
BDE-66 0.9891 0.025 3
BDE-85 0.9930 0.010 4
BDE-99 0.9912 0.010 5
BDE-153 0.9854 0.025 7
BDE-183 0.9900 0.050 12
Pharmaceuticals in sediment
Ethinylestradiol 0.9880 5 6
Dienestrol 0.9947 5 4
Diethylstilbestrol 0.9962 5 3
The limits of detection (LOD), were defined as the
lowest detectable concentration (S/n ≥ 3). The limits of quantification
(LOQ) were estimated as a lowes calibration level
(LCL).
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A n a l y s i s o f R e a l - l i f e S a m p l e s
The ability of the presented technique to determine target
analytes in real life samples was tested at various food
extracts (for pesticides, PCBs) and water samples (for PB-
DEs).
As the example, case of PDBEs in sewage water is presented.
It should be noted that the trace level target analysis
as well as analysis of unknown sample components could be
facilitated when working with TOF mass spectrometers due
to their excellent confirmation power. 10 The identification of
BDE-28 is documented in Fig. 3. Full mass spectrum obtained
as a result of electron ionization (70 eV) was obtained
after automatic spectral deconvolution. This fact proved, that
coupling MEPS with PTV-GC TOF MS would express good
potential for quantification of BFRs at their native concentration
range (10 0 –10 1 ng dm –3 ) in releases of a waste water
treatment plant effluent or sewage water. 11,12 Moreover, such
results showed new possible concepts in rapid water analysis
by employing microextraction in packed sirynge (MEPS)
coupled to PTV-GC TOF MS. This approach minimizes sample
handling and reduces time/cost of measurement.
Fig. 3. MEPS-GC TOF MS analysis of sewage water sample.
(A) TIC chromatogram of sewage water. (b) Zoomed part of
chromatogram – masses 406 + 408 are displayed.(C) Measured
mass spectrum of natively present bDE-28
Conclusions
This study briefly described a relatively fast separation
for analysis of different microcontaminants in food
and environmental samples. High-speed temperature programming
significantly reduced the overall analysis time
as compared to traditional methods. Detection by TOF MS
gives all of the sensitivity needed in order to identify trace
level components while at the same time providing the data
density needed to define narrow GC peaks and deconvolute
overlapping peaks.
Further tests will be facilitated in order to create ultra fast
multimethod for simultaneous detection of wide spectrum of
contaminants by GC-HT TOF MS. The hyphenation of this