MEASUREMENT OF VANADIUM, NICKEL, AND ARSENIC IN SEAWATER AND URINE REFERENCE MATERIALS BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY WITHCRYOGENIC DESOLVATION

Addition of a small dose (2%) of H-2 to the aerosol gas flow enhanced analyte signals by a factor of 2-3, which compensated for the loss of analyte signal that accompanied earlier efforts at cryogenic desolvati on with inductively coupled plasma mass spectrometry (ICP-MS). Vanadiu m, nickel, and arsenic at microgram per liter levels in urine, river, and seawater reference materials were determined. The polyatomic ions ClO+, CaO+, and ArCl+, which normally cause severe overlap interferenc es for these elements, were attenuated to manageable levels by cryogen ic desolvation. The samples were simply diluted with 1% HNO3 so that t he chloride could be removed as HCl. The analytical results obtained f or these standard reference materials agreed closely with the certifie d or recommended values. The detection limit ranges (3sigma) obtained were 10-1000 ng L-1 for V, 0.03-20 mug L-1 for Ni, and 4-7000 ng L-1 f or As in the original samples. The samples were introduced by flow inj ection to minimize clogging of the sampling orifice.