On-line matrix removal and preconcentration using the ESI
seaFAST system coupled to ICP-MS/MS for the ultra-trace
analysis of undiluted seawater
Tristan Zimmermann(1,2), Daniel Pröfrock(1) and Andreas Prange(1)
1) Helmholtz Zentrum Geesthacht, Marine Bioanalytische Chemie, Max-Planck Str. 1, 21502 Geesthacht, Germany
2) Universität Hamburg, Fachbereich Chemie, Anorganische- und Angewandte Chemie, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
Introduction
One of the key problems, when using ICP-MS for the analysis of seawater, are matrix related interferences. The matrix components can cause different issues like the formation of polyatomic interferences, low ionization efficiency
or even the clogging of the sampler cones. Due to these matrix interferences as well as the low concentrations found for most elements (ng/L to sub ng/L) the direct analysis of seawater via ICP-MS remains challenging and still
requires optimisation. To overcome these issues a number of different analytical procedures, like liquid-liquid extraction, coprecipitation or solid phase extraction, have been developed to separate the analytes from the matrix as
well as to enrich them. This poster presentation will focus on the coupling and optimization of the ESI seaFAST system with an ICP-MS/MS (Agilent 8800) for the ultra-trace analysis of undiluted seawater. The optimized method
has been applied for the analysis of Reference Materials and North Sea water samples.
Instrumental Setup


The seaFAST system is an on-line ICP-MS sample introduction system for the ultra-trace analysis of
metals in undiluted seawater.
The preconcentration column chelates a variety of transition metals and rare earth elements (REE) while
matrix components such as Na+, Ca2+, Mg2+ are washed out (see periodic table).

For preconcentration the seaFAST system uses a chelating resin containing iminodiacetic acid (IDA)
and ethylenediaminetriacetic acid (EDtriA) functional groups (see picture below).
The analysis can be divided into four main steps. 1. Loading 2. Rinsing (the column is rinsed with buffer
and MilliQ water, additional measurement in the direct mode) 3. Elution (the targeted elements are
eluted with ultra clean 1.5M nitric acid) 4. Cleaning (rinsing with 1.5M nitric acid and conditioning with
MilliQ water and buffer)

He/H2/O2
RF-coil
torch
Elution profiles of cerium [140 → 156]
8000
Direct mode
Li Be
3
4
11
Blank
quadrupole 1
cones
collision – and
reaction cell
quadrupole 2
6000
detector
19
1 ppt
syringe pump
20
Rb Sr
5 ppt
preconcentration
column
12
K Ca Sc
37
counts
clean up
column
ion lenses
38
4000
56
Ti
V
22
23
21
Y
40
24
41
72
25
42
73
43
74
58
59
75
60
Th Pa
90
91
26
44
27
28
45
29
46
76
9
Cl
16
17
30
47
48
31
32
49
50
33
34
51
52
35
I
53
Pt Au Hg Tl Pb Bi Po At
77
78
61
62
63
79
64
U
80
81
82
83
84
85
66
68
69
70
71
OH
O
O
N
0
67
O
IDA
N
HO
HO
100
65
methacrylate polymer
92
O
80
F
8
S
15
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
89
40
60
time [sec]
O
7
P
14
Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br
Hf Ta W Re Os Ir
57
2000
20
N
6
Si
13
Ac
10 ppt
0
C
5
Al
Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te
39
Cs Ba La
55
B
Preconcentration mode
Na Mg
N
HO
EDtriA
OH
methacrylate polymer
O
Results
Selection of the detection mode

Detection limits
Helium, hydrogen, oxygen and ammonia can be chosen as cell gases. For best detection limits a variety
of metals were measured in all modes including different mass shifts for the oxygen and ammonia mode.
For comparision of the sensitivity the peak areas per ppt for three modes are shown below.


For low detection limits (LOD) low blank values are essential. In the preconcentration mode blanks are
highly influenced by impurities in the buffer and MilliQ water.
A comparison of detection limits is shown below. (calculated by three times the standard deviation of five
blanks)

peak area/ppt
LOD [ppq]
15000
4297.3
He
888.6
H2 (MS/MS on mass)
10000
1103.5
1000
O2 (MS/MS mass shift)
515.8
61.3
100
5000
54.6
51.9
25.1
15

Due to the highest sensitivity, oxygen mode was chosen for the analysis of most REE. The helium mode
was selected for the analysis of the transition metals.
Currently the number of analytes for each sample is limited to 12 isotopes per run due to the Masshunter
software.

Ti

Co
Ni
Cu
Zn
Ti
Co
Ni
Cu
Zn
Y
Cd
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Pb
3.5% NaCl (n=3)
1
Co
Ni
Cu
Zn
Y
Cd
La
Ce
Pr
Nd Sm Eu
Gd Tb
Dy
Ho
Er
Tm Yb
Lu
Pb
Values for CASS 4 are in excellent agreement for both calibration curves. A matrix matched calibration
is not necessary which reduces costs for ultra clean NaCl.
Conclusion





The seaFAST system allows the measurement of ultra-trace elements in undiluted seawater.
The on-line coupling to an ICP-MS/MS operated in the oxygen mode increases the sensitivity compared to
standard helium mode especially for REE.
Due to the high effiency of matrix elimination a matrix matched calibration ist not necessary.
The system provides low detection limits. (2.5-25 ppq for REE and 0.05-4 ppt for selected transition metals)
The measurement of two different seawater SRM´s (CASS4 and NASS5) showed excellent recoverys.
Helmholtz-Zentrum Geesthacht • Max-Planck-Straße 1 • 21502 Geesthacht •
Phone +49(0)4152 87-0 • Fax +49 (0)4152 87-1403 • www.hzg.de • Contact:
Tristan Zimmermann, tristan.zimmermann@hzg.de
Nd Sm Eu
4
4.7
2.7
Y
Cd
La
Ce
Gd Tb
Dy
Ho
Er
Tm Yb Lu
Pb
LOD´s for all REE are in the range of 5 to 15 ppq. Up to 5 ppt could be achieved for Zn which is mainly
affected by blanks.
Measured
Analyte
Value [ppt]
MilliQ (n=3)
Ti
Pr
2.5 3.1 2.5
Recoveries for SRM´s
100
0.1
3.3
CASS 4 (n=10)
To evaluate the efficiency of the matrix elimination the reference material CASS 4 was measured as a
triplicate with two different calibration curves prepared in MilliQ water and 3.5% NaCl in MilliQ water.
10
9.5
3.5
1
conc. [ppt]

12.5
6.1
Efficiency of matrix elimination

10.2 12.7
10
0
12.67
28.33
329.44
618.38
416.59
18.08
26.62
9.71
3.95
1.29
5.66
5.75
0.22
1.28
0.19
1.36
0.36
1.18
0.18
1.12
0.19
19.02
NASS 5 (n=6)
Std. Recovery
[ppt]
[%]
1.37
0.45
7.88
7.49
16.15
0.44
0.53
0.14
0.05
0.02
0.09
0.15
0.01
0.03
0.01
0.06
0.02
0.03
0.01
0.03
0.01
4.28
Measured
Value [ppt]
Ti
Co
Ni
Cu
Zn
Y
Cd
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Pb
12.85
12.63
278.17
334.89
100.68
20.71
24.58
13.35
5.21
1.95
8.99
4.95
0.33
1.75
0.25
1.80
0.44
1.44
0.21
1.39
0.21
8.52
109[ӿ]
105[ӿ]
104[ӿ]
109[ӿ]
86[1]
102[ӿ]
104[1]
102[1]
98[1]
103[1]
100[1]
106[1]
96[1]
98[1]
98[1]
98[1]
98[1]
83[2]
98[1]
105[1]
194[ӿ]
[ӿ]


Analyte
Std. Recovery
[ppt]
[%]
3.22
0.22
6.84
4.69
1.52
1.14
0.70
0.19
0.23
0.08
0.16
0.12
0.01
0.10
0.02
0.08
0.03
0.07
0.02
0.03
0.02
2.01
115[ӿ]
110[ӿ]
113[ӿ]
99[ӿ]
80[1]
107[ӿ]
103[1]
94[1]
92[1]
102[1]
102[1]
108[1]
92[1]
89[1]
93[1]
92[1]
96[1]
101[2]
107[1]
104[1]
107[ӿ]
certified values
For validation two different reference materials CASS 4 and NASS 5 were measured multiple times.
Recoveries for openshore seawater reference material NASS 5 (n=6) and nearshore seawater reference
material CASS 4 (n=10) were in very good agreement to published data.1,2 (no available values for Ti)
References:
1 Bayon, G.,et. al., Multi-Element Determination of Trace Elements in Natural Water Reference Materials by ICP-SFMS after Tm Addition and Iron Co-precipitation, Geostandards and Geoanalytical Research, 38 (1), 2010,
145-453.
2 Lawrence, M.G., et.al., Rare Earth Element Concentrations in the Natural Water Reference Materials (NRCC NASS-5, CASS-4 and SLEW-3, Geostandards and Geoanalytical Research, 2007, 31 (2), 95-103.