Boer, J., de

Covaci, A.

Ryan, J.J.

Schepens, P.

English

Name not available

Determination of PBDEs in human adiposes tissue by large volume injection narrow bore (0.1 mm id) capillary gas chromatography-electron impact low resolution mass spectrometry

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Determination of PBDEs in human adipose tissue by large volume injection narrow bore 
(0.1 mm id) capillary gas chromatography-electron impact low resolution mass 
spectrometry 
A.Covaci', J. De Boer", J,J. Ryan . P. Schepens' 
1 - Toxicological Center, University of Antwerp, 2610 Wilrijk, Belgium 
2 - Netherlands Institute for Fisheries Research, P.O. Box 68, 1970 AB Umuidcn, The Netherlands 
3 - Health Canada, Bureau of Chemical Safety, Ottawa K1A 0L2, Ontario, Canada 
Summary. Human adipose tissue (n=20) from Belgium was analysed for PBDEs using large 
volume injection narrow-bore (0.1 mm id) capillary gas chromatography-electron impact low 
resolution mass spectrometry. Concentrations of PBDEs (sum of BDE 28, 47, 99, 100 and 
153) range between 1.7 and 10.1 ng/g fat and are similar to reported values from Spain and 
Sweden. 
Introduction. Due to their persistance and bioaccumulation potential, polybrominated 
diphenyl ethers (PBDEs) are found in the environment and in humans1. They have been 
measured in adipose tissue samples from Spain2, Sweden3 and Finland4. Because 
concentrations of PBDEs in humans are in the order of ng/g lipid weight, most of the 
analytical work has been carried out by highly sensitive systems as gas chromatography-high 
resolution mass spectrometry5 (GC/HRMS) or gas chromatography-negative chemical 
ionization low resolution mass spectrometry6 (GC/NCI-LRMS). 
Electron impact low resolution mass spectrometry (EI-LRMS) was used mostly for the 
determination of PBDEs in samples with relatively high concentrations7, but its use for 
humans was limited due to lower sensitivity. Here we show that a combination of large 
volume injection (LVI), narrow-bore (0.1 mm id) capillary column and EI-LRMS can be used 
for the determination of PBDEs in human adipose tissue. This is the first report on PBDE 
levels in Belgian population. 
Methods and instrumentation. Human adipose samples (n=20) were obtained by autopsy 
from the Universitary Hospital of Antwerp, Belgium. One gram of each sample was 
accurately weighted and mixed with anhydrous Na2S04 till a fine floating powder was 
obtained. After addition of 100 ul of internal standards (13.06 pg/ul in iso-octane from a 
mixture of '3C-BDE 47, 99 and 153), the powder was extracted by automated hot Soxhlet for 
171 
2 hours with 75 ml of hexane : acetone : dichlormethane = 3:1:1 (v/v). After concentration 
and determination of lipid content, the extract was subjected to clean-up on 2 successive solid 
phase cartridges containing acid silica and acid silica : neutral silica : deactivated basic 
alumina (from top to bottom), respectively. PBDEs (and PCBs) were eluted with 50 ml 
hexane. The eluate was concentrated to almost dryness and 100 ul of the recovery standard 
(bromobiphenyl (PBB) 80 - 18pg/ul in iso-octane) was added, after which it was 
reconcentrated to approximately 60 ul. 
A Hewlett Packard 6890 GC was connected via a direct interface with a HP 5973 mass 
spectrometer. A 10m x 0.10mm x O.lOum AT-5 (5% phenyl polydimethyl siloxane) capillary 
column (Alltech) was used with helium as carrier gas at constant flow of 0.4 ml/min. Twenty 
ul (4x5 ul) were injected in a Gerstel (CIS 4) PTV in solvent vent mode (vent flow 100 
ml/min for 1 min, injector at 70°C for 1.1 min and then heated with 700°C/min to 270°C) 
with the split outlet opened after 2.1 min. The interface temperature was set at 300°C. The 
temperature program of the AT-5 column was 2.2 min at 70°C, 40°C/min to 230°C, 25°C/min 
to 280°C, 5 min at 280°C. The LRMS was operated at 70 eV in selected ion monitoring (SIM) 
mode. Dwell times were set at 10 msec. Two most abundant ions were monitored for each 
level of bromination for native and labeled PBDE. Retention times, ion chromatograms and 
ratio of the monitored ions were used as identification criteria. A deviation of ion ratios of less 
than ±20% from the theoretical value was considered acceptable. 
172 
Results and discussion. The targeted compounds eluted from the GC column between 6.1 
and 9.2 min. The short retention times are due to the use of a narrow-bore capillary column 
(id=0.1mm), which offers the resolution power of conventional column (id=0.25mm), but 
decreases the analysis time with more than 50% (Figure 1). Furthermore, the smaller id results 
in a smaller peak width and an increased mass sensitivity (higher S/N ratios for the same 
amount injected). Thus, for human samples with relatively high concentrations of PBDEs 
(adipose tissue), it is possible to use EI-LRMS with sufficient accuracy. Moreover, with the 
introduction of extract volumes up to 20 u.1, low detection limits (DL) can be achieved (Table 
1). A good linearity (r2>0.995) was achieved for each compounds between 2 x DL (calculated 
for a S/N=3) and 10 ng/g fat. Recoveries of internal standards, '3C-labeled BDEs (calculated 
based on PBB 80 added prior to injection) were between 81 and 103% with a standard 
deviation of less than 21% (Table 1). Analysis of two samples of biota (eel and porpoise liver) 
used for the first interlaboratory test on PBDE8, showed a variation of 10-15% from mean 
values. 
Concentrations of PBDEs in Belgian adipose tissue were ranging between 1.70 and 10.13 
ng/g fat. This is in concordance with concentrations reported in other countries2"4. 
Interestingly, BDE 47 was not always the most abundant congener. Higher values of BDE 
153 were obtained in some samples. Blanks were run to check for interferences, but no 
significant contribution to these high values was observed. Similar trends were seen in some 
samples (n=13) from Spain" (Table 1). Following the addition of appropriate internal 
standards, the extraction and clean-up procedure allowed also the determination of PCBs and 
DDTs on the same sample aliquot. Low correlation coefficients were obtained between 
PBDEs and PCBs (r2=0,34) or PBDE and age (r2=0.07). Meneses2 has observed in 13 
samples that the highest as well as the lowest levels of PBDEs correspond to elder men, while 
for other persistent organohalogenated contaminants (PCBs, DDTs) older persons were found 
to have higher levels due to bioaccumulation and long-half lives of the compounds. 
Table 1. Acquisition parameters and concentrations of targeted compounds in Belgian human adipose tissue 
samples (n=20). 
Target 
compounds 
BDE 28 
L,C-BDE47* 
BDE 47 
"C-BDE 99* 
RT 
(min) 
6.18 
7.03 
7.03 
7.94 
Ions 
406, 408 
496, 498 
484, 486 
576,578 
Recovery 
(%) 
81 ± 12 
84 ± 17 
DL 
(ng/g fat) 
0.05 
0.1 
Mean ± SD 
(ng/g fat) 
0.11 ±0.07 
1.45 ± 1.01 
Range 
(ng/g fat) 
nd-0.26 
0.54-4.71 
Spain", 
(ng/g fat) 
1.36 
173 
BDE99 
BDE 100 
"C-BDE 153* 
BDE 154 
BDE 153 
Sum BDE 
Sum PCBs 
7.95 
7.72 
9.16 
8.92 
9.17 
564, 566 
564, 566 
496, 498 
484, 486 
484, 486 
103 ± 21 
0.15 
0.15 
0.25 
0.25 
0.29 ±0.38 
0.48 ± 0.34 
nd 
1.47 ±0.70 
3.73 ±2.11 
830.8 ±428.5 
nd-1.61 
n d - 1.50 
nd 
nd-2.79 
1.70- 10.13 
263.4-1757.4 
0.42 
0.51 
nr 
1.83 
nd-not detected, nr-not recorded 
When compared with HRMS, EI-LRMS are instruments easy to maintain and operate. It also 
allows the use of 13C-labeled standards as internal standards (this procedure is not possible 
when using NCI-LRMS). Moreover, the higher selectivity of EI is important compared to NCI 
where often only Br ions can be measured. However, the response factors in EI are very 
different for congeners with different degree of bromination. Thus, detection of highly 
brominated congeners is problematic in EI-LRMS, due to low concentrations to be measured 
and poor sensitivity. It is possible to tune manually the MS to obtain increased sensitivity for 
higher masses. The problem can be overcome by using large volume injection which allows 
the introduction of a larger amount of extract, thus increased sensitivity. However, the clean-
up procedure should be very efficient as interferences may easily disturb the chromatogram. 
Conclusions. GC/EI-LRMS in combination with LVI and narrow bore capillary column was 
found suitable for the determination of major PBDE congeners in 20 human adipose tissue 
samples from Belgium and may serve as an alternative for GC/NCI-MS and GC/HRMS. 
References 
'De Wit, C, Organohalogen Compounds, 1999, 40, 329-332. 
2Meneses, M., Wingfors, H., Schumacher, M, Domingo, J.L., Lindström, G., van Bavel, B., Chemosphere, 
1999, 39(13), 2271-2278. 
3Lindström, G., van Bavel, B., Hardell, L., Liljegren, G., Oncol. Rep., 1997, 4, 999-1000. 
4Strandman, T., Koistinen, J., Kiviranta, H., Vuorinen, P.J., Tuomisto, J., Vartiainen, T., Organohalogen 
Compounds, 1999, 40, 355-358. 
5Meironyté, D., Noren K., Organohalogen Compounds, 1999, 40, 379-382. 
''Sjödin, A., Hagmar, L., Klasson-Wehler, E., Kronholm-Diab, K., Jakobsson, E., Bergman, A., Environ Health 
Perspect., 1999, 107, 643-648. 
7Lindtröm, G., Wingfors, H., Dam, M., van Bavel, B., Arch. Environ. Contam. Toxicol., 1999, 36, 355-363. 
8De Boer, J., Organohalogen Compounds, 2000, 45, 118-121. 
174 
Figure 1. Selected ion chromatograms of a human adipose tissue extract: l3C-labeled BDEs 
(chromatogram A) and target PBDEs (chromatogram B). 
A b u n d a n c 
A 
W i u A ^ i W^vWi^J1 ' 
lff|'i<Vl mm i^i# 
T i m e ( m i n ) 
ÜM 
M 
* * k * i 
B 
Vu,M#V ^ * " 
^wX^/VW» 
175 


Environ Health Perspect.,

Organohalogen Compounds,

de Boer, J.

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Determination of PBDEs in human adiposes tissue by large volume injection narrow bore (0.1 mm id) capillary gas chromatography-electron impact low resolution mass spectrometry

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