Application of hyphenated ICP-MS approaches for the analysis
of emerging contaminants in the marine environment
Daniel Pröfrock and Andreas Prange
Helmholtz-Zentrum Geesthacht Zentrum für Material und Küstenforschung, Biogeochemistry in Coastal Seas, Department Marine Bioanalytical
Chemistry, Max-Planck Straße 1, 21502 Geesthacht, Germany, daniel.proefrock@hzg.de
Introduction
Instrumentation and Conditions
Optional gases
Helium
The continuous and still growing anthropogenic impact on marine ecosystems recently results in a rising number of international
agreements and new legislative requirements, which demand the monitoring of a wide range of both priority and new substances
of concern steadily released into the aquatic environment. Such quantitative analysis of priority hazardous substances in the
environment becomes more and more a challenge since new legislations requires also more sensitive methods for the
determination of already defined priority compounds or newly emerging contaminants at low concentration levels. As an example
the EU Water Framework directive (WFD) defines an EQS value (Environmental Quality Standards) of 0.5 ng/L for the sum of all
PBDEs, which should not be exceeded. In consequence the reliable determination of PBDEs at such low levels requires method
LOQs smaller than 30 % of the EQS value, which finally corresponds to an LOQ of 0.15 ng/L for each congener! HPLC-APCI-MS
as well as GC-MS represent widely used methods for the analysis of various contaminants within typical environmental samples
such as water, sediments or biota. The main challenges for these methods are lower detection limits and the extension of the
number of detectable congeners due to improved chromatographic resolution. The complementary application of ICP-MS as a
(hetero)element specific detector for the sensitive determination of e.g. brominated flame retardants via their hetero(element)
content, indicates some potential related to the determination of such contaminants within environmental samples. Within this
contribution we will describe different aspects of the method development and optimization of GC-ICP-MS for the analysis of
hetero(element) containing compounds.
GC
Agilent 6890 GC
ICP-MS
Agilent 7700x
Column
Agilent DB5 MS, 15m,i.D.
0.25µm, 0.1µm film
thickness
RF Power
850 W
3 way optional gas controller
Carrier gas ICP-MS controlled
Helium 2.5 mL/min
Plate bias
-100 V
Injection
1µL, COC, 100°C
Extraction lens 1
-100 V
Oven program
Carrier gas
Start 100°C, 30°C per
minute up to 300 °C, 5 min
at 300°C
Deflection
10 V
GC Interface
Agilent GC Interface
Cell gas
Helium 2.0 mL/min
Cones
Load Coil
Lens system
Torch
ICP-MS
Transferline
300°C
Octopole bias
-16 V
Ar carrier flow
0.95 L/min
Quadrupole bias
Additional
plasma gas
N2, 22 psi (GC controlled)
Isotopes / Dwelltime
Heated transfer line
-14 V
79
Br (0.1 s), 81Br (0.1 s),
126
Xe (0.05 s), 35Cl (0.1 s)
Fused silica capillary
Test conditions: Repetitive GC-ICP-MS analysis of a 1/100 dilution of NIST 2257 CRM 38 PBDE congener mixture, 7-40μg/L”+
18 PCBs, 100 μg/L , 1 µL injection, calculation of the S/N ratios for every compound.
Method optimization and analytical figures of merrit
120000
10 cm behind the transfer line carrier gas inlet
300
100000
80
30
20
10
Intensity
60000
Intensity
40
79
79
50
80000
No PBDE 209
detectable!
40000
PBDE
100
PBDE
47
600000
500000
PBDE
153
400000
PBDE
28
300000
250
PBDE
209
PBDE
99 PBDE
154
Signal to Noise (S/N)
Br (cps)
60
Br (cps)
700000
70
Signal to Noise (S/N)
900000
0.2 cm behind the transfer line outlet within the injector
800000
90
PBDE 209
detectable!
PBDE
183
200000
600
650
700
750
800
850
900
950
1000
1050
150
100
50
?
0
20000
0
200
0
100000
1100
1
2
0
PBDE 47
PBDE 100
PBDE 181
PBDE 196
PBDE 208
PBDE 99
PBDE 154
PBDE 185
PBDE 191
0
5
25
35
0
5
10
15
20
0
PBDE 99
PBDE 154
Carrier Gas [L/min]
PBDE 28
PBDE 47
PBDE 100
PBDE 181
PBDE 196
PBDE 208
1,2
1,3
PBDE 185
30
35
900
1200000
800
1100000
700
1000000
1000000
Br (cps)
1300000
900000
800000
79
700000
600000
500000
900000
800000
700000
600000
500000
100
0
0
0
5
0
10
15
20
25
30
35
40
0
45
5
10
15
20
25
30
35
40
Peak area
RSD %
Inst. LOQ
(μg/L)
250
1
PBDE 28
6,047
200
2
PBDE 47
3
4
fg on column fg on column (GC(ICP-MS)
NCI-MSD)(Fitz 2010)
0,009
4,8
0,05
25
400
7,290
0,017
5,6
0,05
27
1200
PBDE 100
8,373
0,011
6,5
0,05
24
200
PBDE 99
8,764
0,009
4,6
0,05
27
300
5
PBDE 154
9,717
0,009
3,9
0,05
24
300
6
PBDE 153
10,276
0,007
3,2
0,05
27
500
7
PBDE 183
11,730
0,010
4,6
0,06
28
200
8
PBDE 209
21,322
0,010
8,7
0,08
30
100
300
100
PBDE 28
PBDE 47
PBDE 100
PBDE 99
PBDE 154 PBDE 153 PBDE 183
Compound
S/N improvement after purification of the carrier gas
argon using a H2O, O2 and activated carbon trap
15
PBDE 100
PBDE 181
PBDE 196
PBDE 208
Peak to peak signal to noise for PBDE 28
Compound
0
10
PBDE 47
20
25
PBDE 99
30
PBDE 154
35
PBDE 185
40
PBDE 191
Sensitivity improvement due to N2 addition to the plasma
Analytical Figures of Merrit
50
5
PBDE 28
45
Retention time (min)
Average retention time Retention time
(n=9)
RSD %
PBDE 191
N2‐Gasflow [psi]
Effect of the bromine specific optimization on the sensitivity of the GC-ICP-MS setup
Peak
No.
150
PBDE 208
100000
450
350
PBDE 196
5
PBDE 185
200
200000
0
4
PBDE 154
300
200000
100000
Retention time (min)
S/N without Ar Purification
S/N with Ar purification
PBDE 181
PBDE 99
400
300000
Influence of different carrier gas flow rates on the PBDE
detection
400
PBDE 100
500
400000
PBDE 191
PBDE 47
600
300000
400000
PBDE 28
S/N improvement under optimized cell gas settings
1100000
Intensity
40
1,1
25
1200000
79
60
1
20
Retention time (min)
Intensity
80
Signal to Noise (S/N)
30
1300000
Br (cps)
Signal to Noise (S/N)
100
0,9
20
Influence of the GC capillary position within the GC-ICP-MS interface on the detection of PBDE209
120
0,8
15
Retention time (min)
Effect of different Rf power settings on the PBDE detection
0,7
10
Signal to Noise (S/N)
PBDE 28
0
3
He‐Cellgas [ml/min]
Rf Power [W]
200
180
Pressure (Pa)
1 Pump
160
Backing pressure
4.3 *102
2.98 *102
Interface pressure
4.29 * 102
3.15 * 102
Analyser pressure
-4
4.56 * 10-4
140
2 Pumps
120
100
5.01 * 10
80
60
40
20
0
1 Pump
2 Pumps
Number of fore vacuum pumps
Influence of different vacuum pump configurations on the
Br detection using GC-ICP-MS
Quantification of selected PBBs in marine mammal fat tissues using GC-ICP-MS
9,0E+06
8,0E+06
8,0E+06
PBB
155
Br (cps)
6,0E+06
5,0E+06
79
PBB
49
4,0E+06
PBB
153
PBB
52
3,0E+06
Sample N1
PBB
26
2,0E+06
1,0E+06
PBB
153
8,0E+06
0
5
10
15
20
25
30
35
5,0E+06
4,0E+06
3,0E+06
Sample N2
PBB
49
6,0E+06
PBB
153
5,0E+06
4,0E+06
3,0E+06
2,0E+06
2,0E+06
1,0E+06
1,0E+06
Sample N3
PBB
26
0,0E+00
0
40
PBB
52
7,0E+06
6,0E+06
0,0E+00
0,0E+00
PBB
155
9,0E+06
PBB
49
7,0E+06
Intensity
Intensity 79Br (cps)
7,0E+06
PBB
155
Intensity 79Br (cps)
9,0E+06
5
10
15
20
25
30
35
0
40
5
10
15
20
25
30
35
PBB 38
GC-MSD
PBB 38
GC-ICP-MS
PBB 49
GC-MSD
PBB 49
GC-ICP-MS
PBB 52
GC-MSD
PBB 52
GC-ICP-MS
PBB 80
GC-MSD
PBB 80
GC-ICP-MS
PBB 155
GC-MSD
PBB 155
GC-ICP-MS
PBB 153
GC-MSD
n.d.
n.d.
11.7±0.8
11.68±1.75
3.25±0.03
4.69±0.83
n.d.
n.d.
5.89±0.11
9.85±1.93
0.95±0.04
N2
n.d.
n.d.
n.d.
n.d.
33±2.3
30.9±2.39
n.d.
n.d.
n.d.
n.d.
33.9±0.7
23.23±1.36
11.7±0.2
N3
n.d.
0.3±0.09
n.d.
n.d.
10.0±1.0
7.32±1.1
3.65±0.02
2.94±0.52
n.d.
n.d.
6.65±0.2
6.17±0.52
2.39±0.06
PBB 169
GC-ICP-MS
PBB 26
GC-ICP-MS
0.48±0.2
PBB 169
GC-MSD
PBB 26
GC-MSD
n.d.
PBB 153
GC-ICP-MS
Sample
N1
Coelution
PBDE 154
n.d.
n.d.
n.d.
n.d.
n.d.
n.d.
Coelution
PBDE 154
Coelution
PBDE 154
Sample preparation:
Around 5 g fat tissue were weight
into pre cleaned vials, homogenized and further processed
using Soxhlet extraction. After the
measurement of the fat content,
three H2SO4 clean-up steps and an
LC fractionation step the sample
was ready for analysis.
Conclusion
¾ A careful instrumental optimization is necessary to benefit from the potential of ICP-MS as a detector for hetero elements such as bromine, in particular when operated at
dry plasma conditions as realized by using GC-ICP-MS.
¾ The high sensitivity and its tolerance against co-eluting sample constituents make GC-ICP-MS an interesting alternative beside GC-MS for “untypical application” such as
the analysis of hetero atom containing organic contaminants like PBDEs. An additional enrichment step as well as instrumental changes will help to further improve the
sensitivity.
40
Retention time (min)
Retention time (min)
Retention time (min)