Designing an In-Situ Device for Desalinating Extraterrestrial Amino Acid Samples
Abstract
With the discovery of water-based plumes on Enceladus, the likely liquid ocean on Europa, and potential subglacial liquid water and Recurring Slope Linea on Mars, there has been an increased interest in developing in-situ instruments for discovering biogenic precursors such as proteins and amino acids. Previous work has been done to make such devices, however the sensitivity of these detection methods is hindered by the expected high salinity of extraterrestrial samples. In this work, we outline a robust method to purify amino acids independent of the type and concentration of ionic contaminants. This technique can be used as a single sample purification tool for multiple downstream analytical instruments. Though similar methods have been used to desalinate meteorite samples on Earth, this has yet to be attempted for a remote landing site, or to detect all twenty proteinogenic amino acids. Here we describe the separation achieved using a meso-scale ion exchange chromatography column with a three-step wash process.The column is washed with a low pH buffer to retain amino acids, a water wash to remove contaminants, and then a high pH buffer to release the bound amino acids. Separation efficiency and yield for both salts and amino acids were measured using a conductivity probe and UV/Vis spectrometer, respectively. Three aromatic amino acids (tryptophan, tyrosine, and phenylalanine) have been successfully purified from saturated salt solutions down to the millimolar level. The effect of different amino acids, salts, and loading concentrations has been explored to determine operational limits and optimize sample purity. This technique allows for non-destructive sample preparation to remove ionic interference, minimize loss of amino acids, and increase downstream detection sensitivity. Our next steps of implementing this technology into modular microfluidic chips will allow it to be tuned to different environments (salts, soils, acids, etc.) and detection methods.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P52C..14V
- Keywords:
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- 6297 Instruments and techniques;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS