Evelyn Frères

PhD student
University of British Columbia

I’m a Graduate student of Geological Sciences in the M.Sc. Program of the Dept. of Earth, Ocean and Atmospheric Sciences of the University of British Columbia.

I’ve majored in Chemistry at the Federal University of Rio de Janeiro (Brazil) in the beginning of 2014. But ever since my first year of college, I’ve always worked (first as a Scientific Initiation student, then as a proper Chemist) at the Centre for Mineral Technologies (CETEM, in Rio de Janeiro/RJ, Brazil) with Geochemical Analysis, having had the chance to develop and collaborate with several research projects (some of them supported by PETROBRAS, a major Brazilian oil company). Most of them involved the development of methods for the chemical characterization of a whole variety of mineral samples.

I’ve always been interested in science (at age 10, I wanted to be an astronomer – not an astronaut, an astronomer). So, when the time came for me to decide what to do after college, the path was pretty clear: pursuing a career in research. And (always) keep studying.

My research at UBC, as a M.Sc. student and a MAGNET Trainee under the supervision of Dr. Dominique Weis, is focused on studying the mechanisms of oxide formation in MC-ICP-MS and understanding how it influences instrumental mass bias. Multiple Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) is a technique that has been widely used to precisely measure isotopic ratios in geological samples at ppm or even ppb levels.  However, because certain processes inherent to this technique (such as sample introduction, ionization and mass separation) cause mass fractionation, isotopic ratios measured using MC-ICP-MS are always biased from their “true” value, even in the absence of spectral interferences. Nd is a very important element in geochronology. 147Sm decays to 143Nd with a very long half-life of approximately 106 billion years. This characteristic causes the changes in Nd isotopic ratios to be really small, therefore requiring the analysis to be very precise. However, Nd often presents a non-linear mass dependant fractionation correlated to the formation of NdO+ species that cannot be corrected by standard mass fractionation laws. Therefore, in order to make precise and accurate measurements of Nd isotopic ratios, it is important to have a better understanding of that phenomenon. The aim of my project is to study the effects of changing the instrument operating conditions in the formation of NdO+ and observing how those varying parameters will affect the measured isotopic ratios. These study results should be used to develop a robust analytical method for the measurement of Nd isotopic ratios using MC-ICP-MS.