From Perchlorate in breast milk to Perchlorate on Mars


Tuesday, March 22 2016 - 12:00 pm, PDT
Sandy DasGupta
UT Arlington

The Phoenix mission to Mars clearly demonstrated the usefulness of wet chemistry analyses to understand the composition of planetary surfaces, and it tentatively revealed the presence of ~0.5% of perchlorate by weight of Martian soil. This talk will explore why open tubular ion chromatography (OTIC) is the necessary next step in wet chemistry analyses for planetary exploration, both in terms of technical feasibility, and science versatility. We will discuss the performance of OTIC in comparison to other approaches such as capillary electrophoresis. Jorgenson, the father of capillary zone electrophoresis, reportedly joked about his invention: Capillary electrophoresis is a wonderful technique but it has only three small problems: Injection, Separation and Detection. In OTIC, a sample is injected into a conduit and a response is recorded with or without eluent suppression. In general, open tubular liquid or ion chromatography is time efficient only in very small capillaries where the Jorgenson triad of problems intensify. In recent years we have learned how to inject pL-multi-nL volumes of samples in the same setup, generate active chromatographic surfaces within capillaries as small as 5 mm in bore and learned to make miniature detectors to detect analytes sensitively in such small tubes. The prospects of working meaningfully on this planet with practical inexpensive equipment (less than $1000 for a high performance chromatograph!) will also be discussed.


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