Dissolved Cd, Co, Cu, Ni, Mn and Pb along the CLIVAR I8S ... · Dissolved Cd, Co, Cu, Ni, Mn and Pb...

Dissolved Cd, Co, Cu, Ni, Mn and Pb along the CLIVAR I8S/I9N Indian Ocean transectsPeter Morton1, Angela Milne2, William Landing1, Chris Measures3, Clifton Buck1, Kathleen Gosnell4, Maxime Grand3, Mariko Hatta3, and William Hiscock3

1Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, Florida, USA

2School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, UK 3Department of Oceanography, University of Hawaii-Manoa, Oahu, Hawaii, USA

4Department of Marine Sciences, University of Connecticut, Groton, Connecticut, USA

Project Overview Automated Trace Metal ExtractionBuilding on the method developed by Milne et al. 20102, we have automated much of the time-consuming process of extracting and preconcentrating trace metals from seawater.

References1 C.I. Measures, W.M. Landing, M.T. Brown, C.S. Buck, Limnol. Oceanogr.-Meth., 6 (2008) 384.2 A. Milne, W.M. Landing, M. Bizimis, P.L. Morton, Anal. Chim. Acta, 665 (2010) 200.

February-April 2007

Samples collected using CLIVAR trace metal rosette1

Twelve 12-L GO-Flo bottles 80 stations, 12 depths per station 1000 dissolved trace metal samplesCollected into acid-washed 125 mL LDPE bottles Acidified to 0.024 M HCl (using 6 M quartz distilled HCl)

To explore the biogeochemistry of dissolved trace metals in the Indian Ocean, from the Bay of Bengal to the Antarctic margin

Region of Study

Sample collection

Preparing the CLIVAR trace metal rosette for deployment

Sample analysisDissolved Fe and Al measured shipboard by Grand, Hatta, and Measures (data not shown) Dissolved Cd, Co, Cu, Mn, Ni, and Pb measured at Florida State University

y = 89355x + 87731R² = 0.9995

y = 96802x + 16288R² = 0.9998

y = 91268x + 650R² = 0.9982

y = 110203x + 214024R² = 0.9994

y = 79737x + 31617R² = 0.9982

y = 89609x + 43790R² = 0.9996

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Mn Standard Addition slopes

Results, to dateContoured trace metal data are shown with overlays of related physical parameters.

OCE 0649639

Method highlights40x sample preconcentration (20 mL into 0.5 mL)Streamlined UV-oxidation (minimal sample transfer)Automated sample uptake and elutionOnline buffering to pH 5.8-6.2 (ammonium acetate, 0.4 M)Six hours to extract 24 samples

System componentsNobias Chelate PA-1 chelating resin (polycarbonate column)Cetac ASX-500 Autosampler (sample uptake)Cetac ASX-100 Autosampler (fraction collector)Dynamax Rainin RP-1 peristaltic pumpsVici 10-port injection (2 position) valve

All components coordinated with FloZF v5.0 (GlobalFIA)

Extraction sequencePrecondition system with UV trace metal-free seawaterSample uptake: 10 minute 2 mL/min flow rateRinse: 1 mL UHP water (18 Mohm-cm)Elution: 0.5 mL 1.0 M HNO3 (QD or Optima)Wash: 1 mL 1.0 M HNO3 (QD or Optima)Conditioning: 4 mL 0.08 M NH4-acetate

QuantificationThermo ELEMENT 2 HR-ICP-MSIsotope dilution: Cd, Cu, Ni and PbStandard additions: Co and Mn

Certified against SAFe S, D1 and D2

Similar slopes indicate consistent buffering throughout extraction