Application of capillary electrophoresis interfaced to double focusing sector field ICP-MS for nuclide abundance determination of lanthanides produced via spallation reactions in an irradiated tantalum target

An analytical procedure was developed using capillary electrophoresis (CE) coupled on-line to a double-focusing sector field inductively coupled plasm a mass spectrometer (DF-ICP-MS) for the analysis of mixtures of lanthanide elements in aqueous samples with natural isotope abundances and in a sample taken from an irradiated tantalum target containing artificial nuclide abu ndances. A MicroMist AR30-1-F02 nebulizer with a Cinnabar small volume cycl onic spray chamber was used for ICP-MS sample introduction. The CE-ICP-MS i nterface featured a self-aspirating electrolyte make-up solution for electr ical ground connection and control of nebulizer suction. The CE-ICP-MS meth od features fast run times and small sample sizes (approximate to 35 nL inj ection volume). Detection limits for the most abundant lanthanide isotopes were 0.72 ppb to 3.9 ppb, an improvement of as much as one order of magnitu de compared to a quadrupole ICP-MS system using a similar experimental arra ngement. Abundances of the most abundant isotopes of lanthanides were found to be within 0.1-2% of table values for natural samples while isotopes pre sent in smaller amounts were within 3-5% of table values. The method was ap plied to samples taken from a tantalum material which was exposed to a high energy proton beam for the production of neutrons via spallation reactions . A large fraction of the spallation products were lanthanides containing n uclide abundances unlike natural samples. Thus, a chemical separation step prior to ICP-MS detection was required to avoid isobaric interferences for the accurate determination of nuclide abundances in such samples. The resul ts of the nuclide abundance determinations were compared to theoretical cal culations.