Dr. Eric Bakker
Univeristy of Geneva, Switzerland
Host: Dr. Karin Chumbimuni Torres
Title: Electrochemical and Optical Sensing Chemistry for Aquatic Analysis
Abstract:
It is widely recognized that dynamic environmental systems should preferably be monitored in situ, as traditional sampling and off-site analysis will invariably alter local equilibria, especially with chemical species that are kinetically labile and reactive. Unfortunately, very few such species can today be monitored reliably, as only pH sensors are integrated in the ubiquitous CTD (conductivity–temperature–depth) probes.
This presentation will show how advances in fundamental concepts in our analytical chemistry research laboratory are being integrated into field deployable devices. Development of all-solid-state ion sensors have recently made it possible to construct robust in situ potentiometric sensing probes, for example for the profiling of ammonium in stratified lakes. Exhaustive thin layer electrochemistry started out as a fundamental idea to achieve increased robustness, as Faraday's law dictates that this is a potentially calibration free method. It has now been demonstrated in freshwater and marine field deployments to be a promising methodology for the direct detection of total alkalinity and chlorinity. Thin layer electrochemistry provides an attractive solution for inline desalination and acidification, allowing one to detect nutrients in seawater by direct potentiometry.
The last part of the talk will move the discussion to imaging tools for the spatially resolved observation of chemical dynamics. Our group is currently working on closed bipolar electrodes to achieve this goal, using an array of ion-selective electrodes that are electrically detached from the power source. This will eventually allow one to electrochemically control an array of sensors by a single potentiostat and using imaging cameras for detection.
Biosketch:
Eric Bakker obtained his doctoral degree in Analytical Chemistry in 1993 at the Swiss Federal Institute of Technology (ETH) in Zürich, Switzerland. He then spent 14 years in the United States (University of Michigan, Auburn University, and Purdue University) and three years at Curtin University in Perth, Western Australia, before returning to Switzerland in 2010 for his current position. His research is in chemical sensors, using electrochemistry and optics to achieve a sensitive and robust detection of electrically charged species. In recent years the field of application has moved to environmental systems. His over 300 papers have been globally cited more than 19,000 times. Among his awards is the 2014 RSC Robert Boyle Prize in Analytical Science.