Use of Ion Molecule Reactions in Inductively Coupled Plasma Mass Spectrometry(ICP-MS) to Improve Selenium Analysis and Detection
Loading...
Date
2006-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
The Ohio State University
Abstract
ICP-MS measurement of selenium, an essential trace element and potential cancer preventative, is complicated by argon-containing molecular ions at each of the selenium isotopes. SeH+ complicates measurement of tracers based on isotope ratios when methane is used in a dynamic reaction cell to remove the argon-containing molecular ions. Nitrogen and oxygen were tested as alternative reaction gases Methane, nitrogen and oxygen all reacted with ArAr+, ArxH+, Ar2H2+ and ArCl+ Methane, nitrogen and oxygen reduced the ArAr+ signals by 7, 5, and 2.6 orders of magnitude, respectively, with minimal loss of Se+ signal (less than an order of magnitude). The Ar2H+ and Ar2H2+ also react rapidly with each of the reaction gases; however, these reaction rates could not be accurately determined due to the low background equivalent concentration that occurs as a result of their signal. The ArCl+ signal can be reduced by up to 5 orders of magnitude by ion-molecule reaction with methane and up to 4 orders of magnitude with nitrogen. The SeH+ signals increase to about 7% of the corresponding Se+ signal when methane is used as the reaction gas. The SeH+ signals are less than 1% of the corresponding Se+ signal when N2 or O2 reaction gases are used. Isotope ratio precision and accuracy were also assessed in order to determine how small the concentration of a 77Se spike concentration could be accurately measured in the presence of naturally occurring Se in blood plasma and other human biological samples.
Description
Denman Undergraduate Research Forum 3rd Place
Keywords
ICP-MS, ICP-QMS, ICP-DRC-MS, ICP-SF-MS