A new isotope dilution inductively coupled plasma mass spectrometry (ICPMS) method is developed to determine picomolar concentrations of titanium (Ti) in seawater. The method applies Mg(OH)2coprecipitation to concentrate Ti from seawater, and uses a new49Ti-47Ti isotope dilution to eliminate the need for separating Ti from seawater Ca, resulting in an isobaric interference-free analysis by high-resolution multicollector ICPMS. The method uses a 1.8 mL seawater sample with a detection limit of 1.6 pmol L-1that is determined mainly by Ti contamination during sample preparation rather than by ICPMS sensitivity, instrumental Ti background, or isobaric interferences. An oceanographically consistent vertical profile of dissolved Ti in the Sargasso Sea near Bermuda is measured with this method.
ASJC Scopus subject areas
- Analytical Chemistry