@article {2307, title = {Cyanobacterial copper-binding ligands isolated from artificial seawater cultures}, journal = {Marine Chemistry}, volume = {110}, number = {1-2}, year = {2008}, note = {ISI Document Delivery No.: 313BETimes Cited: 4Cited Reference Count: 34Wiramanaden, Cheryl I. E. Cullen, Jay T. Ross, Andrew R. S. Orians, Kristin J.}, month = {May}, pages = {28-41}, type = {Article}, abstract = {This paper demonstrates a method to isolate and characterise strong biogenic copper-binding ligands from an artificial seawater matrix. Pseudo-polarography is used to detect the ligands, determine their ionic strength-corrected binding constants, and track them through each step of the extraction process. Two ligand types are found, one strong and one relatively weak, with log K{\textquoteright} values of 49.4 +/- 1.1 and 19.8 +/- 5.5 respectively, assuming that the metal is bound as copper(II). If a copper(I) complex, the log K{\textquoteright} of the strong copper-binding ligand would be 25. Pseudo-polarography is then used to assess different resins for ligand extraction and to determine the eluent fraction in which the strong ligand is recovered. XAD-16 is found to be a suitable resin for extracting the strong binding ligand from salt water into methanol, suggesting that the ligand is weakly hydrophobic. As ligands are identified by their complexation of copper, no assumptions are made regarding the functional groups of these natural ligands. The copper-binding ligands are successfully extracted into solvents suitable for mass spectrometric analysis using soft ionisation methods such as electrospray and MALDI. (C) 2008 Elsevier B.V. All rights reserved.}, keywords = {AFFINITY-CHROMATOGRAPHY, chemical speciation, COMPETITION TECHNIQUE, COMPLEXING LIGANDS, copper, CU STRESS, EMILIANIA-HUXLEYI, IONIZATION MASS-SPECTROMETRY, LIGANDS, mass, NORTH PACIFIC, ORGANIC-COMPLEXES, polarography, SARGASSO SEA, sea water, SPECTROMETRY, TRACE-METALS}, isbn = {0304-4203}, url = {://000256715300004}, author = {Wiramanaden, C. I. E. and Cullen, J. T. and Ross, A. R. S. and Orians, K. J.} } @article {4348, title = {The determination of dissolved zirconium and hafnium from seawater using isotope dilution inductively coupled plasma mass spectrometry}, journal = {Marine Chemistry}, volume = {60}, number = {3-4}, year = {1998}, note = {ISI Document Delivery No.: ZR467Times Cited: 23Cited Reference Count: 22}, month = {Apr}, pages = {245-255}, type = {Article}, abstract = {This paper describes the development of an analytical technique utilizing isotope dilution and inductively coupled plasma mass spectrometry (ICP/MS) to determine the picomolar and femtomolar concentrations of dissolved Zr and Hf found in seawater. Data acquired using this technique are presented to verify the method; in the subarctic North Pacific Zr ranges from 25 to 366 pmol/kg and Hf from 0.20 to 1.02 pmol/kg, with concentrations increasing smoothly with depth. The chelating ion-exchange resin, Chelex-100, was found to be suitable for the extraction/concentration step required for the determination of dissolved Zr and Hf in seawater using isotope dilution analysis. The extraction was optimized for pH, flow rate, resin volume, elution volume, and the time required for isotope equilibration. The isotope ratios Zr-91/Zr-90 and Hf-178/Hf-177 were measured using flow injection ICP/MS. The detection limits for a one litre sample are 0.21 and 0.03 pmol/kg for Zr and Hf, respectively. The analytical precision (Is) of the technique improves with increasing concentration and varies from 7\% at 42 pmol/kg to 2.5\% at 280 pmol/kg for Zr and from 22\% at 0.28 pmol/kg to 9\% at 1.4 pmol/kg for Hf. (C) 1998 Elsevier Science B.V.}, keywords = {aluminum, ATLANTIC, ATOMIC-ABSORPTION SPECTROMETRY, Chelex-100, hafnium, ICP-MS, OCEAN, SEA-WATER, SEAWATER, trace metals, TRACE-METALS, ZIRCONIUM}, isbn = {0304-4203}, url = {://000073979800008}, author = {McKelvey, B. A. and Orians, K. J.} }