Passive sampling as a tool for time-integrated analysis of
metal and metal species in marine waters using ICP-MS-MS
Jördis Petersen1,2, Daniel Pröfrock1, Jose A.C. Broekaert2, Andreas Prange1
1Helmholtz-Centre-Geesthacht,
2University
Institute of Coastal Research, Max-Planck-Str. 1, 21502 Geesthacht, Germany, joerdis.petersen@hzg.de
of Hamburg, Department of Chemistry, Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany
Introduction
The monitoring along with the assessment of the current status of the marine environment within the context of the EU Water Framework Directive (WFD) or the Marine Strategy Framework Directive (MSFD)
requires new approaches for the accurate and sensitive determination of contaminant levels. Many contaminants show very low concentrations in the water phase. The application of time-integrating sampling
approaches namely passive and active sampling offers interesting perspectives to solve some of the difficulties related with conventional spot sampling. In comparison to conventional spot sampling passive
sampling allows the detection of very low concentrations. Furthermore passive samplers enrich the freely available dissolved fraction of pollutants in water and thus give information on the bioavailability.
Here we describe some first results related to the development of a new approaches for the monitoring of selected trace elements in marine waters using passive sampling. Currently the most commonly used
passive sampling devices for time-integrated analysis of metals and metal species are DGT (diffusive gradients in thin films) as well as the so called Chemcatcher® -Metal.
ICP-MS-MS has been used for the first time to analyse passive sampling extracts providing the necessary sensitivity as well as some new possibilities to deal with certain interferences.
Experimental setup and conditions
Chemcatcher-Metal®
Field exposure of passive sampling devices
DGT
The Chemcatcher®(1) consists of a chelating disk and a cellulose
acetate membrane.
For the permanent deployment of integrative sampling
devices fixed experimental platforms have been realized
at two location in the German North Sea.
The principle of DGT(2) technique is based on diffusion of metals through
a membrane-diffusive layer (hydrogel + membrane filter) and their
accumulation in a resin gel (polyacrylamide).
Preparing the Chemcatcher® before exposure
Assembling of the
Chemcatcher® body
Membrane filter
Diffusive gel
Receiving phase
Sampler body
Diffusion membrane
Resin gel
Sampler body
Receving phase
Conditioning of Chelating Disk
Assembling of a commercially available
DGT device
Field deployment for a
defined exposure time
Soaking membrane in 1 % HNO3 overnight
Passive sampler devices
Mussel cages
Sediment trap
Preparation of the Chemcatcher® after field deployment
Preparation of DGT after field deployment
Conc. HNO3
3 M HNO3
Remove
receiving phase
Measurement of
the extracts with
ICP-MS-MS
Receiving phase
Agilent 8800 ICP-MS Triple Quad
He H2 Xe
NH3 O2
Retrival of the deployed
Chemcatcher®
torch
quadrupole 1 collision – and
reaction cell
cones
quadrupole 2
detector
Conclusion
ICP-MS-MS
Passive sampling systems
Comparison of detection limits of selected trace elements
between ICP-MS and ICP-MS-MS
Recovery Chemcatcher® for selected
trace metals
0,0020
DL QQQ
D e te c t io n L im it ( µ g /L )
D e te c t io n L im it ( µ g /L )
DL 7500CX
0,100
0,050
0,000
DL QQQ
DL 7500CX
0,0015
0,0010
0,0005
0,0000
V
Cr
Recovery of the field
deployed DGTs,
ion lences
Results
Ti
Resin gel
Overnight extraction of the receiving
phase with 1 mL of conc. HNO3
RF-coil
Extraction of the receiving phase with
20 mL of 3 M HNO3
Sc
Remove
receiving phase
Measurement of
the extracts with
ICP-MS -MS
ESI SC-4DX Fast Autosampler
0,150
Field deployment for a defined
exposure time
Fe
Co
Element
Ni
Cu
Ge
As
Se
La
Tb
Ho
Lu
Pt
Au
Tl
Pb
Bi
Th
Element
U
The Chemcatcher® is adapted to
accumulate
selected
metals
shown by recovery experiments.
A recovery of nearly 100% has
been found for a selection of
metals .
U
Pb
Lu
Yb
Tm
Er
Ho
Dy
Gd
Tb
Eu
Sm
Nd
Pr
Ce
La
Sn
Cd
As
Cu
Ni
Cr
0
50
100
Recovery in %
150
• First results indicate that the selected passive sampling
tools allowed the enrichment and calculation of time
weight average concentrations for the selected metals
• The application of ICP-MS-MS provides improved Limits
of Detection for most elements compared to results
obtained by conventional collision cell ICP-MS
• Even in matrix-rich samples interferences could be
strongly minimized due to the new possibilities of ICPMS-MS
200
Outlook
Comparison of recovery for selected elements of reference
material (SRM 2976) between ICP-MS and ICP-MS-MS
Measurement of Time weighted average concentration (cw) of
selected trace metals at the station Cuxhaven
• Next experiments will target the in deep evaluation of
external influences on the uptake rate of the samplers
such as flow velocity, temperature and salinity.
• This knowledge will allow to improve the future
calculation (3) of time weight average water
concentrations measured by passive sampling
Helmholtz-Zentrum Geesthacht • Max-Planck-Straße 1 • 21502 Geesthacht • Phone +49 (0)4152 87-1843 • Fax +49 (0)4152 87-1875 • joerdis.petersen@hzg.de
References :
(1)Kingston, J; Greenwood R, Mills GA, Morrison, GM and Björklund-Persson, L (2000): Development of a novel passive sampling system for the timed-averaged measurement of a range of organic pollutants in aquatic environments. J Environ Monit 2: 487–495.
(2)Zhang H, Davison W (1995): Performance Characteristics of Diffusion Gradients in Thin Films for the in Situ Measurement of Trace Metals in Aqueous Solution. Anal.Chem.67, 3391-3400.
(3)Vrana B, Mills GA, Dominiak E, Greenwood R (2006): Calibration of the Chemcatcher passive sampler for the monitoring of priority organic pollutants in water. Environ. Poll. 142, 333-343.