(258c) Advancement of the Microfluidic Mars Organic Analyzer Platform for Detection of Organic Biomarkers: Amines, Amino Acids, Aldehydes, Ketones, Carboyxlic Acids, and PAHs

Previously, our group created the Mars Organic Analyzer (MOA), microchip CE system for amine and amino acid analysis. Here we present recent work that has extended the MOA's capabilities, via new derivatization and separation chemistries, for analysis of aldehydes, ketones, carboxylic acids, and polycyclic aromatic hydrocarbons. The integration of pacific blue labeling of amino acids increases our sensitivity 250-fold to unprecedented sub parts per trillion levels and permits separations via micellar electrokinetic chromatography (MEKC). The resolution obtained by traditional CZE methods is improved, and when combined with MEKC, pseudo-2D separations allow for enhanced compositional analysis and unambiguous peak identification. Advances in analytical protocols and buffer chemistry have improved the robustness of our CE system when analyzing samples with extreme levels of salinity or pH such as Rio Tino sediments or Saline Valley brine samples. These samples represent places where only extremophiles dwell and, prior to this work, pathologically difficult to analyze by standard electrophoretic methods. We have also analyzed other Martian analog samples (e.g. Murchison Meteorite, Atacama Desert), an environmental sample for PAH analysis, and a simulant of an astrochemistry reaction producing complex organics such as amino acids and dipeptides.

Additionally, oxidized forms of carbon, aldehydes, ketones, and carboxylic acids can now be analyzed with the Mars Organic Analyzer (MOA). Fluorescent derivatization is achieved in ~ 15 min by hydrazone formation with Cascade Blue hydrazide to aldehydes and ketones in 30 mM borate pH 5-6. Labeling of carboxylic acids is achieved by addition of EDC, an activating agent, to the aldehyde and ketone reaction. A carbonyl standard consisting of ten aldehydes and ketones found in extraterrestrial matter and environmental samples is successfully separated. Limits of detection for the components of the standard depend on the reactivity of the compound and range from 70 pM for formaldehyde to 2 uM for benzophenone. To explore the utility of this method for analyzing complex samples, analyses of several wine varietals are conducted, identifying 10 aldehydes and ketones ranging from 30 nM to 5 mM.

Since little is known about the organic chemistry of Mars or other extraterrestrial bodies, any comprehensive organic chemical analysis suite should include the capability to detect and quantify these partially oxidized organic molecules with high sensitivity. Our techniques have additional capabilities required for in situ astrobiological analysis, including the absence of organic solvents, highly fluorescent probes yielding high sensitivity to organic biomarkers, portability, and ease of automation. The chemistries and separations are incorporated into microfabricated bioanalysis system for sample preparation and analysis and are amenable to use in biomedical devices for metabolic analysis.