2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
P21 ChALLENGES IN ThE ANALySIS OF
hExAbROMOCyCLODODECANE IN ThE
ENVIRONMENTAL SAMPLES
PETRA HRáDKOVá, JAn POUSTKA, JAnA
PULKRABOVá, MICHAELA náPRAVníKOVá and
JAnA HAJŠLOVá
Department of Food Chemistry and Analysis, ICT Prague,
Technická 3,166 28 Prague 6, Czech Republic,
petra.hradkova@vscht.cz
Introduction
Brominated flame retardants (BFRs) are compounds
widely used in commercial products to reduce and prevent
the extent of fire. Hexabromocyclododecane (HBCD) is the
third most produced BFR worldwide and the second most
used BFR in Europe. HBCD is mainly applied as an additive
flame retardant for the expanded and extruded polystyrene
which are used as insulation materials in buildings and in the
upholstery textile.
As the HBCD is not chemically bound to the material
to which is added, it could leak into the environment through
emission during a production or use of various materials,
from final products or following disposal. Similarly to other
BFRs, HBCD is a persistent, bioaccumulative and toxic chemical.
There are theoretically 16 HBCD diastereoisomers,
however, the technical mixture consists mainly from three
diastereomeric pairs of enantiomers (α-, β- and γ-HBCD), the
latter one is the most abundant (75–85 %).
Both GC-MS and LC-MS are commonly used techniques
for the quantitative determination of HBCD. Total-
HBCD (sum of α-, β- and γ-HBCD) may be measured by GC-
MS, but it does not allow the quantification of the individual
isomers, because the HBCD diastereoisomers can rearrange
above oven temperature of 160 ºC and also resolution of GC
separation is not sufficient. The individual HBCD diastereoisomers
can be determined using LC-MS/MS. On the other
hand, the response in this system may be influenced by matrix
ion suppression especially in the electrospray ionisation
MS 1,2,3,4 .
In this study, the both types of analytical systems were
tested to assess the ways of HBCD determination in the
environmental samples.
Experimental
The choice of environmental samples was based on: (i)
a representativeness of both biotic and abiotic components
and (ii) origin from Czech environment. The final extracts
of tested samples including target analytes were analysed by
two different chromatographic systems:
• GC-MS (using negative chemical ionization mode (nCI)
with quadrupole analyzer)
• LC-MS/MS (using negative electron spray ionization
(ESI–) with tandem quadrupole analyzer).
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S a m p l e T r e a t m e n t
The fish muscles of species chub (Leuciscus cephalus)
and bream (Abramis brama) represented biotic environmental
samples. The chub and bream frequently occur in Czech
rivers, are very suitable as a bioindicator of the aquatic
environment contamination and were caught in the Vltava
River. Also sediment and sewage sludge represented other
analysed samples. The sewage sludge was collected in a
sewage treatment plant (STP) and the river sediment was collected
downstream from this STP, both in Hradec Králové.
The individual standards of α-, β- and γ-HBCD diastereoisomers
were obtained from Cambridge Isotope Laboratories
(CIL, UK).
The samples (sediment and sludge after drying) were
desiccated with anhydrous sodium sulphate and then extracted
in a Soxhlet apparatus using a solvent mixture n-hexane:
dichloromethane (1 : 1, v/v) for fish and DCM in case of sediment/sludge.
The crude extracts were rotary-evaporated to
dryness. Lipid content of fish samples was determined gravimetrically.
In next analytical step, the samples were re-dissolved
in 10 ml of ethylacetate: cyclohexane (1 : 1, v/v). The
fat and other co-extracted compounds were removed by a gel
permeation chromatography (GPC). Finally, a target fraction
was rotary-evaporated and concentrated in isooctane and in
acetonitrile for GC and LC analysis, respectively. GC extract
was in addition treated with concentrated sulphuric acid prior
the analysis.
I n s t r u m e n t a l D e t e r m i n a t i o n
The target analytes were separated using either gas or
liquid chromatography. An Agilent 6890n gas chromatography
(GC) coupled to an Agilent 5975 Inert XL mass spectrometer
(MS) was operated in nCI mode (both Agilent, USA).
The system was equipped with a 15 m × 0.25 mm × 0.1 µm
DB XLB capillary column (J&W Scientific, USA). The temperature
of the column was programmed from 80 °C (2 min)
to 325 °C at a rate of 50 °C min –1 and held for 5 min. Helium
was used as a carrier gas at ramping flow from 1.5 ml min –1
(7.2 min) to 3 ml min –1 at a rate of 50 ml min –1 (ref. 2 ). The ion
source, quadrupole and interface temperature were 150 °C,
150 °C and 300 °C, respectively. Bromine isotopic ions
[Br] – at m/z 79, 81 and molecular ions [Br 2 ] at m/z 158 and
160 were monitored for confirmation HBCD in selected ion
monitoring (SIM) mode.
A high performance liquid chromatograph carried out
with a Waters Alliance 2695 HPLC instrument (USA) together
with a Quattro Premier XE tandem-quadrupole mass
spectrometer (Waters, USA) was operated in negative electrospray
ionization (ESI–). The LC separation of the compounds
was performed on a nUCLEODEX beta-PM chiral column
(200 × 4 mm id, 5 µm, Macherey-nagel), kept at 40 °C, using
an (A) methanol, (B) acetonitrile and (C) deionized water
gradient. The gradient was programmed as follow: 30 % (A),
30 % (B) and 40 % (C), 0–3 min linear change to 30 % (A),
60 % (B) and 10 % (C), 3–20 min kept this composition.