Evelyn Freres

MSc Geological Sciences

MAGNET Trainee

EOS-Main 305

My research here at UBC, as a Ph.D. student and a MAGNET Trainee is focused on studying instrumental mass bias in MC-ICP-MS.

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, during the sampling, ionization and mass detection processes, mass fractionation can occur, causing the true ratio to differ from the measured one.

It is widely known, however, that certain phenomena such as oxide formation, matrix effects, and concentration effects (also known as “self-induced matrix effect”) can cause changes in the magnitude of MC-ICP-MS mass bias and add a non-linear component to it. These effects can cause the traditional mass-fractionation laws (that are used to correct for mass bias) to be insufficient in correcting the measured ratios for this added mass fractionation. So, in order to obtain accurate and precise numbers when measuring isotopic ratios in MC-ICP-MS, accounting for such phenomena is of the utmost importance.

Therefore, my research is focused in understanding and characterizing the origin and precise effects of these sources of mass bias. This knowledge will allow us to find the best solutions to either minimize these effects, or properly correct for them.

Teaching Assistantships:

August 2009 - July 2012  Teaching Assistant at the Federal University of Rio de Janeiro for the Department of Inorganic Chemistry for the following courses: Experimental General Chemistry II, Experimental Inorganic Chemistry I, and Experimental Inorganic Chemistry II

August 2012 - December 2012  Teaching Assistant at the Federal University of Rio de Janeiro for the Department of Physical-Chemistry for the following course: Experimental Physical-Chemistry I

September 2014 - Present  Teaching Assistant at the University of British Columbia for the Department of Earth, Ocean and Atmospheric Sciences for the following courses: EOSC 111 – Laboratory Exploration of the Planet Earth (2014-2015), EOSC 110 – The Solid Earth: A Dynamic Planet (2015), EOSC 340 – Global Climate Change (2016)