2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
Specific mass transitions (m/z 640 → 79, 81) were used for a
MS/MS determination.
Results and Discussion
The levels of HBCD in selected environmental samples
were monitored using both types of previously described analytical
systems. As mention above, HBCD consists of three
diastereoisomers – α-, β-, and γ-HBCD. Fig. 1. documented
the result of a GC-MS application, this technique does not
enable the isomers separation, all isomers are eluted in one
broaden peak. For this reason, α-isomer is used as a calibrant.
Furthermore, individual diastereomers have different
response factors which can cause that the less accurate results
are obtained in case of higher content of β- and γ-isomers.
Fig. 1. GC-MS chromatogram of hbCD (m/z 79 and 81)
On the other hand, the LC-MS/MS allows separation of
six individual enantiomers as demonstrates Fig. 2.a. The LC
chromatograms show diverse patterns of the isomeric composition.
In the sediment samples (abiotic matrix), as shows
Fig. 2.b, γ-diastereoisomer is usually predominant, followed
by α- and β-HBCD, what reflects the diastereomeric profile
in various technical products. The content of the first isomer
in the biota samples is the inverse and α-HBCD is the most
abundant (no figure). It could be caused by biotransformation
process in live organisms 5 . In addition to ability of excellent
separation of individual enantiomers, LC-MS/MS provides
lower limit of detection (0.5 ng g –1 lipid weight, 0.7 ng g –1
dry mass) in comparison with GC-MS system (0.8 ng g –1 lipid
weight, 0.8 ng g –1 dry mass) in case of fish samples, sediment
and sewage sludge, respectively.
The first results obtained from the analysis of the Czech
environmental samples are resumed in Table I. The chub
and bream livers contained both α-HBCD enantiomers and
at the low concentration also β-enantiomers. The high level
of γ-HBCD was determined in the sample of chub muscle
from Podolí. This significantly higher level of γ-isomer in
biota sample may indicate there is an emission source in
particular locality present, because as mention above, γ-isomer
dominates in technical mixture. The similar pattern of
diastereomers was found also in the sediment and sewage
sludge samples where only γ-HBCD was detected as shows
Fig. 2.b. Comparing the results obtained within our study,
it was found that the GC levels of target analytes are just a
s376
Fig. 2. LC-MS/MS chromatogram of (a) a standard of hbCD
individual enantiomers and (b) a real sample of river sediment
from Hradec Králové
slightly overevaluated by about 13 % in case of α-diatereomers.
Total differences in the results between LC-MS/MS
and GC-MS can be cause by usage of α-HBCD as a calibrant
together with diverse response factor of individual diastereomers
in GC-MS.
Table I
The results of diastereoisomers obtained by LC-MS/MS
and sum of HBCD as a result of application GC-MS in fish
samples (ng g –1 lipid weight) and sediment/sewage sludge
(ng g –1 dry mass)
HBCD
Results of
Fish Locality Diastereoisomers
GC-MS
α β γ
Chub němčice 34 1.4 n.d 36
Bream němčice 68 0.4 n.d. 80
Chub Klecany 6.6 n.d. n.d. 7.5
Bream Lysá 59 1.1 n.d. 69
Chub Podolí 16 6 105 58
Sediment Hradec Králové n.d n.d 28.1 17.7
Sewage Hradec Králové n.d n.d 103.9 156
sludge
Conclusions
In presented study, two different analytical techniques
(GC/MS and LC-MS/MS) were tested for the analysis of
HBCD isomers in environmental samples. The potential of
the first system is particularly in the determination of the total
HBCD occurrence in samples. On the other hand, the latter
one using chiral permethylated β-cyclodextrine stationary
phase allows the separation and quantification of individual
diastereomers. Comparing the results obtained within our
study, it was found that the GC levels of target analytes are
just little overevaluated. For this reason, the need for further
investigations into differences between GC and LC results
are necessary.