Determination of trace elements in filtered suspended marine particulate material by sector field HR-ICP-MS

Quantification of particulate (>0.45 mum) and dissolved (<0.45 <rho>m) trac e elements in seawater is imperative for understanding geochemical cycling in the marine environment. Suspended particulate trace element concentratio ns are typically <10% of total element concentrations in seawater. To overc ome analytical difficulties associated with low analyte concentrations, it is common to filter large volumes (tens to thousands of litres) of seawater . We report a novel method for the rapid quantification of Al (324 ppb), P (159 ppb), V (2.02 ppb), Cr (2.85 ppb), Mn (22.3 ppb), Fe (304 ppb), Co (0. 129 ppb), Ni (0.817 ppb), Cu (1.68 ppb), Zn (3.25 ppb), Mo (0.264 ppb), Ag (0.079 ppb), Cd (0.029 ppb), Ba (3.54 ppb), Pb (1.13 ppb) and U (0.053 ppb) in digest solutions of suspended matter, filtered from 0.2 to 5.0 L of sea water. Filter digest solutions, consisting of a complex matrix of filter re sidue, sea salt, dissolved solids and strong acids, are analyzed on the ELE MENT, a high resolution, inductively coupled plasma mass spectrometer (Finn igan-MAT, Bremen, Germany). High sensitivity (>1x10(6) counts s(-1) ppb(-1) In; with shielded torch) combined with low flow rates (mu Flow nebulizer, Elemental Scientific) provide excellent absolute detection limits (0.4 to 7 20 pg depending on the element). A resolution of 300 (low resolution) is ap propriate for interference-free high mass analytes of interest (Ag, Cd, Pb, Ba and U), whereas 4300 (medium resolution) is sufficient to resolve all p lasma-, water- and matrix-based polyatomic interferences on low mass analyt es (Al, P and first row transition metals). The precision of the method is better than +/-4% for most analytes. Accuracy could not be determined conve ntionally using a certified reference material (not available), but was est imated from spiked samples to be <<plus/minus>4% when calculated using a st andard additions curve and <<plus/minus>10% for most elements if using an e xternal standard curve.