The samples were preserved with either
HNO3 or HCl. Samples that were preserved with HCl were analyzed
with a dynamic reaction cell (DRC) for arsenic to remove the possible
interference from 40Ar35Cl; argon was used as the reactive gas for the
samples preserved with HCl. Multi-elemental standard solutions were
prepared from SPEX CertiPrep, Inc. (SPEX) and Agilent Technologies certified
solutions.