MULTI PHYSICAL-CHEMICAL PROFILER FOR REAL-TIME CONTINUOUS IN SITU MONITORING

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Submarine connectors for: Telemetry, Serial interface, FIA, Fluorescence probe Land Station pH2, 15min FIA, 15 min 100-interconnected Ir-microdisk electrode array pH 2, 62 h Main CPU board FSK telemetry board 100 Fluidic & FIA device drive board 4.12.2001 Pbtot pH2 2h 80 Multiparameter probe board To VIP cell Pbtot FIA 7min electrical contact Pbtot FIA 7min IDRONAUT DE L’ENVIRONNEMENT Smart potentiostat boards Pbdyn VIP/MPCP Sample + L + Acid eq. t = 5 min; Tf = 22°C epoxy resin Pbdyn VIP/MPCP GIME (MPCP cells 1 and 3) CGIME (MPCP cell 2) 60 Pbfree CGIME Pbfree CGIME 0.03 M HNO3 2.3 ml/min Al or Au bonding Mother board & Power supply Cooling coil (V = 4.5 ml/min) 40 containment ring CHIMIE ANALYTIQUE ET BIOPHYSICOCHIMIE 20 Sample + L + Acid eq. t = 5 min; T= 60°C ACID 150 µm Agarose gel Agarose gel LIGAND 0 Buoy Profiler Mercury layer Mercury layer Cu/Cutot Pb/Pbtot 150 µM TRIEN 2.3 ml/min Mechanical & signal connectors Chelating resin Heating coil ( V = 4.5 ml) Si3N4 Si3N4 4 mm Ir Ir VIP cell Si3N4 Si3N4 Silicon 5 µm Sample + L eq. t = 5 min; T = 20°C 5 µm Silicon Preamplifier Cell-2 CGIME 1.8 mm Mixing coil (V = 4.5 ml) Raw Arve sample 2.3 ml/min Cell-1 GIME Cell-3 FIA-GIME . 14 Cutot FIA 7min 140 CutotpH2 2h Cudyn VIP/MPCP Conc. of Cu dynamic fraction (nM) 12 Cutot FIA 7min 120 Cufree CGIME time Cudyn VIP/MPCP Av. conc. RSD % Channel 1 Channel 2 Channel 3 10 100 Cufree CGIME 4.85 10.93 11h30 4.91 4.30 5.36 8 80 Concentration (nM) 4.79 7.10 12h30 5.14 4.79 4.45 Cu specific fractions / Cutot pH 2 (%) 60 6 4.39 2.73 13h30 4.39 4.51 4.27 40 4.57 4.16 14h30 4.74 4.59 4.36 4 - - 15h30 4.30 - 4.28 20 2 Av. conc. 4.69 4.55 4.54 0 0 Pontoon Ingela's Ingela's Alsbäck Alsbäck Ingela's Ingela's RSD % 7.46 4.57 10.10 Pontoon Ingela's Ingela's Alsbäck Alsbäck Ingela's Ingela's 5m-22 30m-22 5m-23 35m-23 5m-26 30m-26 3.5m-21 3.5m-21 5m-22 30m-22 5m-23 35m-23 5m-26 30m-26 3 140 Conc. of Pb dynamic fraction (nM) time Av. conc. RSD % 120 Channel 1 Channel 2 Channel 3 2.5 100 0.45 5.78 11h30 0.43 0.44 0.48 2 0.45 5.78 12h30 0.46 0.42 0.48 80 Concentration (nM) Pb specific fractions / Pbtot pH 2 (%) 1.5 0.37 6.86 13h30 0.39 0.34 0.37 60 0.41 3.70 14h30 0.43 0.40 0.41 1 - - 15h30 0.43 - 0.36 40 0.5 20 Av. conc. 0.43 0.43 0.42 Kristineberg Marine Station Entrance of Gullmarsfjorden RSD % 5.81 9.76 11.91 0 0 Pontoon Ingela's Ingela's Alsbäck Alsbäck Ingela's Ingela's Pontoon Ingela's Ingela's Alsbäck Alsbäck Ingela's Ingela's 3.5m-21 5m-22 30m-22 5m-23 35m-23 5m-26 30m-26 5m-22 30m-22 5m-23 35m-23 5m-26 30m-26 3.5m-21 Conc. of Cd dynamic fraction (nM) time Temperature (°C) Salinity (psu) Av. conc. RSD % Temperature (°C) Salinity (psu) Temperature (°C) Salinity (psu) Channel 1 Channel 2 Channel 3 0 5 10 15 20 25 30 35 40 0 5 10 15 20 25 30 35 40 0 5 10 15 20 25 30 35 40 0.19 10.31 11h30 0.17 0.20 0.21 0 0 0 0.19 11.30 12h30 0.19 0.22 0.17 10 20 10 0.19 10.32 13h30 0.17 0.19 0.21 20 40 Depth (m) 20 14h30 0.22 0.23 - - - Depth (m) Depth (m) 15h30 0.20 - 0.21 - - 30 60 30 Preliminary field tests of the MPCP analytical and technical developments have been performed during a campaign performed at Kristineberg Marine Station – Sweden, August 19-28 2002. The MPCP system integrating 3 GIME sensors was deployed, together with VIP systems, in Gullmarsfjorden at various locations and depths. Laboratory measurements of total extractable Me and free Me ion concentrations using a FIA prototype coupled to the MPCP channel 3 and a CGIME sensor respectively were performed in freshly collected samples. 40 80 40 Av. conc. 0.19 0.21 0.20 RSD % 11.05 8.57 9.01 50 100 50 Ingela’s 22.08.02 Alsbäck 23.08.02 Ingela’s 26.08.02 60 120 60 Typical temparature and salinity profiles measured in two stations of Gullmarsfjorden MULTI PHYSICAL-CHEMICAL PROFILER FOR REAL-TIME CONTINUOUS IN SITU MONITORING OF SPECIFIC FRACTIONS OF TRACE METALS AND MASTER VARIABLES Marylou Tercier-Waeber1, Fabio Confalonieri2, Giuliano Riccardi2, Antonio Sina2, Flavio Graziottin2, Jacques Buffle1 1Dept. of Inorganic and Analytical Chemistry, University of Geneva, 30 Quai E. Ansermet, 1211 Geneva 4, Switzerland. 2Idronaut Srl, Via Monte Amiata 10, Brugherio (MI), Italy. Contact: Marie-Louise.Tercier@cabe.unige.ch INTRODUCTION Development of novel analytical tools allowing real-time and detailed temporal/spatial evolution monitoring of the distribution of specific metal species and master variables is of prime interest. They will enable us to better understand the role and the fate of trace metals in aquatic systems, to develop more accurate predictive models based on biogeochemical processes, to evaluate the impact of human activity on coastal ecosystems and therefore to optimize industrial/social developments. With these goals in mind, we recently started the development of an automated Multi Chemical-Physical Profiler (MPCP). The MPCP is based on the Voltammetric In situ Profiling System (VIP System), which was developed during an European MAST-III project and is now commercialised by Idronaut. The VIP probe is based on a gel integrated microelectrode (GIME) which allows the specific measurement of the concentration of the dynamic fraction of trace metals, defined as the sum of the free metal ions and the small labile complexes with size of few nanometers. The following analytical and technical developments are under way to improvethe capability of the VIP probe: Development of a novel chelating resin-gel integrated microsensor (CGIME) forin situ measurements of free metal ion concentrations Development of a submersible FIA system coupled to one cell forin situ measurements of total extractable metal concentrations Development of an improved VIP voltammetric probe based on 3 flow-through cells and threeindividual potentiostats (MPCP voltammetric probe) for simultaneous in situ measurements of the above three specific fractions of trace metals Incorporation of the MPCP voltammetric probe with external/integrated probes for measurements of master variablesinto abuoy supported automated monitoring system which can be controlled from a land station. MULTI PHYSICAL-CHEMICAL PROFILER MAIN COMPONENTS Schematic diagram of the gel-integrated microsensors Schematic diagram of the MPCP harware Schematic diagram of the submersible FIA and example of analytical conditions used for measurements of total extractable metal concentrations in Arve river samples. MPCP management software Integrated multiparameter probe Example of voltammogram obtained by measurements in Arve river sample using GIME sensor Ratios of total extractable Me conc. (voltammetry) to total Me conc. (ICP-MS ) obtained in an Arve river sample after sample pre-treatments based on: i) acidification and ii) ligand exchange followed by acidification and heating of the sample. The MPCP probe harware and firmware have been developed to allow simultaneous measurement cycles on the three channels. PRELIMINARY FIELD TESTS OF THE MPCP Measurements of trace metal speciation and master variables in Gullmarsfjorden Reproducibility of the MPCP voltammetric probe Example of Cu and Pb specific fraction concentrations measured in Gullmarsfjorden stations, August 21-26 2002 Typical example of the measurement reproducibility of the individual channels and between the three channels of the MPCP voltammetric probe obtained for in situ autonomous measurements over 5 hours using one GIME sensor in each MPCP probe channel. Kristineberg pontoon August 22 2002, deployment depth 3.5 m, SWASV measurement time 20 min. ACKNOWLEDGEMENTS The authors thank: Olivier Guenat and Milena Koudelka-Hep, IMT - University of Neuchâtel, who produce and supply the Ir-interconnected microelectrode arrays used to prepare the GIME and CGIME sensors; David Turner, AMK-University of Göteborg, for all facilities during field work in Sweden; the financial support of the European Commission and the OFES – Switzerland (European EESD program- IMTEC project Contract n° EVK3-CT-2000-00036).